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2.1 Introduction

In this chapter, we treat the basic scientific methods and assumptions used throughout the remainder of the book. We criticize the philosophical method as a way of knowing the causes of values. We also treat the fundamentals of scientific investigation. We discuss evolutionary social theory, distinguish proximate and ultimate causation, and elaborate on the topic of enculturation that was introduced in Chap. 1. We discuss and resolve criticisms of comparative methodology, which is the method we emphasize throughout. Lastly, we comment on ideological criticisms of evolutionary theory applied to human affairs.

2.2 Philosophical Aesthetics Is Not Science

Philosophical aesthetics, the study of the beautiful and the ugly using methods from philosophy, is an old, broad, and diverse field of scholarship. It deals with such topics as the beauty of values, as well as the beauty of facial and other bodily features, natural landscapes, architecture, scents and tastes, and art forms (for reviews, see Thornhill 1998, 2003). Aesthetics became a distinct discipline within philosophy with G. Baumgarten’s Aesthetica, published in 1750, but, as documented by the historian Kovach (1974), speculations by scholars about the nature of beauty and ugliness have been made in the West at least since the sixth century bc in Greece. Philosophical aesthetics applies only pure reasoning to a topic to discover the topic’s essence or reason for being. Aesthetic philosophers tried to understand many domains of natural beauty and ugliness this way, including the aesthetic valuation of different belief systems.

The philosophical method provides only a first step toward producing knowledge of how the universe is. Although thinking is essential for discovery, a fatal problem with philosophy per se is the lack of the necessary follow-up in testing whether the thinking is supported by evidence or is not. In science, the thinking or hypothesis must be transformed into predictions about what will exist in nature if the thinking is accurate. If, upon observation, data of that existence is absent, the thinking is then demonstrated to be inaccurate, and the investigation must go “back to the drawing board” to attempt another thought that may have worth as evidenced by tested, empirical support. If the thinking, when transformed into predictions about nature, leads to discovery, the idea or hypothesis generated by the thinking is supported and hence not falsified. This procedure continues and leads to facts about nature.

This method of knowing is the scientific method. In our opinions, this method is humankind’s most valuable idea. Our ideology is that there is far too much human misery in the world and human misery can be reduced only when its causes are discovered and eliminated. This is where science comes in, because it is the only way to demonstrate causation. Science does not tell us that a moral world is one without genocide, fascism, racism, classism, sexism, and rape, but, through its ability to determine the causes of those happenings, it can facilitate progress toward achieving such a world if its findings are used in relevant social policy. The scientific method is humanity’s nascent path to a world more benevolent and egalitarian than ever imagined by liberal idealism.

In the mid to late 1800s, and in biology’s most foundational research, Charles Darwin extended scientific methodology to the study of evolutionary history. Darwin’s method of historical science is the method used for understanding deep-time historical causes that are unobservable when they cause their effects. Contrary to arguments by some creationists and accommodationists, we can fully know deep-time historical causation, even though we cannot observe it directly as it happened. As Ghiselin (1969) pronounced, the general method of historical science that Darwin invented has “triumphed.” It is straightforward and powerful. Consider this: scientific hypotheses conjecture possible causation, to be tested by empirical evaluation of predictions or consequences. This means that scientific hypotheses about evolutionary histories conjecture possible causation, such as common ancestry of different species or processes of Darwinian selection, which acted in the deep-time past. Actual deep-time historical causes have consequences, which are the predictions offered by evolutionary historical hypotheses to be evaluated through empirical research. Darwin’s method can penetrate vast stretches of deep-time history to identify causation; it is applied respectfully and productively not only in biology, but also in all other sciences charged with understanding the distant past, including geology and astronomy. In this book, we apply Darwin’s method of historical science to illuminate the evolutionary history of people’s values.

The scientific method first arose and was widely discussed and applied during the Scientific Revolution of 1500–1700, which, in turn, fueled the Age of Reason between 1600 and the early 1800s. The Enlightenment was the period of 1700–1800 within the Age of Reason. The Age of Reason was a widespread intellectual movement emphasizing rationalist, antiauthoritarian, liberal, humanitarian, and scientific values, and de-emphasizing tradition, religion, and authority as sources of knowledge. This reduction in the salience of religion in people’s values was and is called secularism.

Secularist thinking that excludes science is pure old philosophy—speculation without empirical test—and alone cannot give knowledge of the world. As one noted preacher, Martin Luther, put it, “reason is the devil’s greatest whore” (see http://en.wikiquote.org/wiki/Martin_Luther). He meant that reason is a powerful lure that can pull one down the path of false and trivial thought (in Luther’s religious moral view, the path of sin) (Pelikan and Lehmann 1955–1986). Secularist rationalism has no more claims on truth than religion or other ideology. Regardless of how principled and objective a philosopher’s thoughts seem to be, they are trivial until they show claim to empirical ground through testing. The scientific method is the guillotine for thought incapable of discovering the empirical reality of nature.

Aesthetic philosophy, then, is an anachronistic and failed way of knowing because it cannot empirically falsify or verify hypotheses. As a result, it has been replaced by science. Science is the study of cause and effect using the scientific method. The effects of interest to scientists are the world around us as it is. Each of the three major branches of science—biology, chemistry, and physics—is charged with understanding the causes of the effects or features in its research domain.

2.3 Biology Encompasses All Life

The adjective “biological” is defined typically as, of or pertaining to life. Biology is the scientific study of all of life’s features. Examples of subdisciplines of biology are anthropology, biochemistry, botany, economics, entomology, ethics, genetics, history, linguistics, ornithology, paleontology, parasitology, physiology, political science, psychology, sociology, and all other fields engaged in study of life. The dichotomy of social versus biological made by some is highly erroneous, because many of life’s effects are social interactions, which are mediated by environmentally cued computations in brains. Using biological as a synonym of genetic is misinformed profoundly too, because genetics is only one of many subdisciplines of biology. Moreover, genetic causes have no primacy among all the causes of biological features (see below).

Scholars are evolved social animals and hence are socially competitive. Ideas and values, inside and outside scholarly realms, are major tools of social competition (Alexander 1979a, b; Flinn 1997). As a result, many areas of scholarly study of people have arisen because they provide useful means of social competition for their originators and followers. Regardless, all the areas of science dealing with life, including all those dealing with human activity, are necessarily tied together conceptually by, and anchored in, the fact that all life’s history on Earth was an evolutionary history involving two distinct categories of evolutionary causation creating each feature or trait of individual organisms: (1) phylogenetic origin of the trait, and (2) the trait’s maintenance after its origin. In fact, there is simply no such thing as a nonevolutionary study of humans because humans are evolved animals. Likewise, there is no such thing as a nonbiological study of humans because humans are living things. Hence, all studies of humans are evolutionary and biological studies. These studies only differ in their degree of sophistication in using evolutionary theory to make discoveries about humans. This dimension of difference, however, is huge. Many scholars in research areas investigating human affairs lack an understanding of evolutionary biology and its heuristic power for illuminating human behavior. Ignoring evolutionary theory in research on any topic of life amounts to ignoring the most basic and fundamental knowledge for understanding the topic.

Yet, researchers in the many traditions of human scholarship not informed by evolutionary theory are increasingly realizing that biology’s general theory and Darwin’s method of historical science are essential for creating new and empirically fruitful ideas and testing those ideas. As an example, the economist Robert Frank recently discussed why this is so for economic scholarship. (See his article in The New York Times, July 12, 2009.) Our book is a testament to the utility of the parasite-stress theory of values for informing many fields of human scholarship, and, most importantly, for their empirical and conceptual synthesis. Just as research in economics is severely intellectually limited when not inspired by Darwinism, so is that in political science, anthropology, history, psychology, sociology, medicine, and so on across all the fields that investigate matters of human life. It is our hope that the parasite-stress theory of values will be an important bridge between evolutionary theory and the scholarly traditions that have ignored evolutionary theory.

2.4 Other Reasons Why Philosophical Aesthetics Failed

2.4.1 Common Sense Is Biased

By far the greatest hindrance and aberration of the human understanding proceeds from the dullness, incompetency, and deceptions of the senses; in that things which strike the sense outweigh things which do not immediately strike it, though they be more important. —Francis Bacon (Novum Organum, Book I, 1620)

We have given some explanation earlier of why pure philosophical reasoning itself cannot, and without scientific testing, discover the causes of nature. There are additional fatal problems with pure reasoning as a way of knowing. Fundamentally, thinking and deduction are biased, i.e., prejudiced, by intuitions and common sense interpretations that arise from personal values. The psychological machinery of human reasoning and deduction was favored by Darwinian selection because it promoted the reproductive success of those who reasoned and not because it yielded knowledge of the causes of nature’s features. Given that human reasoning is biased, as Bacon realized, testing of the empirical implications of thoughts is the only path to discovery of how nature actually is. Because of cognitive biases, to stop at thinking and not test the thinking cannot answer any question about nature.

Common sense, intuition, and emotional validation of ideas actually can be impediments to discovery, because much of the true world is counterintuitive. The Earth is not flat, nor is it the center of the universe, as most thought prior to the relevant scientific discoveries. Life’s history on Earth, including that of humans, was an evolutionary history despite the intuitions and common sense that say otherwise to the majority of people. The causes pertaining to the evolution of life, particularly those about the evolution of human behavior and psychology, are often counterintuitive, in part because evolution involves ultimate causes—those that acted prior to the conception and development of the sapient humans who try to contemplate causation (for further discussion, see Goddard 2009).

We have considerable personal experience with the difficulties in teaching university and college undergraduates and university graduate students about evolutionary biology and its application to human behavior and psychology. Thornhill has done so for 40 years. In order to understand themselves, other people, and life in general, students first must be made aware of their fundamental and pervasive reliance on value-based common sense and intuition rather than on scientific evidence. Once that awareness is deeply comprehended and constantly kept in mind, students can become scientifically objective in viewing themselves and others.

2.4.2 Intuitions Vary Because Core Values Vary

People experience and understand the world in terms of their personal moral or value system, which results in a powerful bias in people’s thinking. Furthermore, as we show in detail in Chap. 4, the differences are large between conservatives and liberals in intuition and cognition (e.g., Jost et al. 2003, 2009; Carney et al. 2008). For example, collectivists interpret events in the context of the events’ relation to in-group togetherness, maintenance, and goals, whereas individualists interpret events as independent of the in-group (Hofstede 1980). Recall, collectivists have an interdependent view of their world, whereas individualists see things as independent. A simplification of a lot of interesting research in educational psychology is the following. A kindergarten teacher holds up an egg and then asks small children to describe the last time they had cooked and eaten eggs. Collectivist children describe family members interacting and cooperating to cook eggs—their thinking is in-group in focus. In contrast, individualist children focus on events and phenomena that are mentally independent of the in-group—they describe the various physical properties of eggs (Trumbull et al. 2001).

Other examples of the distinctly different cognitive styles of collectivists and individualists include collectivists’ mental rigidity toward valuing traditional and conformist views—i.e., dislike of change because of its perceived threat to stability and security—in contrast to the open-mindedness and preference for change of individualists (Jost et al. 2003; Carney et al. 2008). This is sometimes described as collectivist neophobia (fear and dislike of new or different ideas and ways) and individualist neophilia (Thornhill et al. 2010). This difference is seen in attitudes about the validity of science and intellectual activity in general, as well as in attitudes about new technology—conservatives are more negative, and liberals are more supportive and open (Jost et al. 2003, 2009; Thornhill and Fincher 2007; Carney et al. 2008; Ferris 2010). What people find funny also depends on their value system. Conservatives enjoy humor that is unambiguous and has closure; liberals respond more positively to humor that has ambiguity and lacks closure (Ruch and Hehl 1983). Also, a difference in thinking between conservatives and liberals is observed when past events come to mind. Conservatives interpret their past in more positive terms than do liberals (Thornhill and Fincher 2007). As a final example, conservatives endorse and support human inequality, whereas liberals endorse and strive for equality, as in all people are equally human and important (Carney et al. 2008; Jost et al. 2009). Both conservatives and liberals are using behavioral displays of values in socially strategic ways—that is, to gain social resources in their respective value-based social niches.

The differences in cognitive styles described in the examples just mentioned reflect those at the two ideological poles. Collectivism–individualism is a continuous variable across individuals (Chap. 4). Hence, any given topic will be seen in a range of ways across people, depending upon where each person falls on the values’ continuum. Information processing and deduction are value laden, and values vary among people. Hence, views of reality and priority vary among people. The scientific method is the only known method of knowledge gain that can distinguish how the world actually is versus how people interpret it or want it to be as part of their personal value system.

Aesthetic philosophers tried to solve the question of the nature of a beautiful versus ugly idea or value, using only their biased value systems. “Beauty is truth” was a perpetual and central argument in traditional philosophical aesthetics (Kovach 1974). This arose from the view that beauty, or what makes you feel good to see, hear or think, is therefore morally good, while ugly, or what feels bad, is morally bad. In scientific practice, motional validation of something experienced, in itself, does not count as evidence.

2.4.3 Personal Introspection Is Incomplete Analytically

Another problem with philosophical aesthetics for gaining knowledge is that much of the information processing involved in aesthetic judgment and associated reasoning is not available to analysis by introspection. Even in the imaginary world of a person without any values at all (hence his or her thoughts could not be biased), the causal basis of judgment and action remains unavailable to personal introspection. Most human mental activity is not experienced consciously. For instance, the mental activity that causes routine respiration and blood circulation is continuous, but this information processing is regulated by psychological adaptations that do not produce consciousness. Beauty experiences are felt consciously, but the specific information processed by psychological mechanisms that generates the experiences is not. Given this, thought per se cannot identify the causes of beauty judgments, including the causes of aesthetically pleasant and unpleasant values. Science is required to identify the data processed that result in aesthetic judgments. Conscious beauty experiences upon encountering a beautiful human, habitat, or ideology can be even profound, positive experiences, and so is the case of encountering the opposite of beauty. The conscious profundity of certain aesthetic judgment misled early scholars in philosophical aesthetics to reason that they could identify by reasoning alone the causes of the experiences (Thornhill 1998, 2003).

As Kaplan (1992) pointed out for landscape aesthetic judgments, the preferences are made rapidly and effortlessly, but research subjects’ explanations of their choices have no relationship to the differences that are associated empirically with preferred and nonpreferred landscapes. The same is seen in people’s judgments of physical attractiveness of faces and bodies: they are made rapidly and effortlessly and without awareness of the features actually assessed (e.g., symmetry) or the features’ relationships to health or, more accurately, to phenotypic/bodily quality (for reviews see Thornhill and Gangestad 1993, 1999a, b, 2008).

Moral disgust is a strong emotion felt when a person or group’s behavior violates what is considered to be moral by the person disgusted (Tybur et al. 2009). This is felt without knowledge that the behavioral norm violation is an indication of out-group threat and associated novel infectious-disease threat (Chap. 3; Curtis 2007; Schaller and Murray 2008; Oaten et al. 2009; Inbar et al. 2012).

2.5 Scientific Aesthetics

For the reasons discussed, the understanding of aesthetic judgments, including those made about morals or values, was not advanced by philosophical aesthetics. In large contrast, scientific aesthetics has greatly advanced knowledge of aesthetic judgments. Scientific aesthetics uses the scientific method to determine the causes of experiences of attractiveness of things, including values, and why beauty assessments exist in the first place.

Scientists studying aesthetics are pursuing knowledge of the two categories of causation in biology, proximate causes and ultimate causes. Proximate causes are those that act during the lifetime of the individual to bring about their effects. These causes include physiology, psychological mechanisms, development (sometimes called “ontogeny”), genes, cues or stimuli arising from the ecological ambience, and information processing. Ultimate causes act in the deep-time past to bring about their effects—they are the evolutionary causes. Proximate and ultimate causes in biology are complementary causes, not competitive/alternative ones. Complete knowledge of a biological effect of interest, such as the mockingbird’s song or a person or group’s values, requires knowledge of both proximate and ultimate causation of the effect.

2.6 Categories of Ultimate Causation

As mentioned earlier in this chapter, ultimate causes are of two categories. One is the evolutionary origin (often called “phylogenetic origin”) of a feature on the Tree of Life—the feature’s debut in life’s history on Earth. Novel traits/phenotypes arise on the tree from developmental processes that modify preexisting traits; developmental causes of phylogenetically new phenotypes are ultimate causes because they brought about effects—new phenotypes—by acting in the deep-time past. When the new phenotype and the preexisting phenotype differ genetically, the potential is created for changes in allele frequencies—that is, for evolution (West-Eberhard 2003). The second category of ultimate causation is the maintenance of the trait after its phylogenetic origin. Maintenance causes are the evolutionary agent’s Darwinian selection and drift. Selection for a trait may be the result of the trait itself as the actual target of selection (direct selection). In this case, the trait itself increases reproductive success of individuals that bear it and therefore is favored by selection. Or the selection for the trait may be the result of its correlation with another trait that selection actually favors (indirect selection). Directly selected traits are called evolved adaptations, and indirectly selected traits are called incidental effects/by-products. The two categories of ultimate causation—origin and maintenance—are complementary: comprehensive understanding of ultimate causes of any feature of life requires knowledge of both its evolutionary origin as well as its maintenance after it first appeared on the Tree of Life (Thornhill 2007).

2.7 By-products

By-products are traits that have been maintained evolutionarily because they are linked to features that are directly selected. The color of chicken egg yolk is not an evolved adaptation; it is a by-product of a maternal care adaptation: the carotenoid pigment deposition in the yolk giving its color actually functions to nurture the developing embryo in the egg. There was direct selection in the past for carotenoid deposition in the egg because it increased maternal reproductive success, while the color itself is incidental to this functional effect and was indirectly selected. Similarly, in mammals, nipples of males are a by-product of female nipples; the nipples of females were directly selected and function in delivering milk to young offspring.

Many human values and associated behaviors are by-products of adaptation, meaning they are not the effect that gave rise to direct selection. That is, they are not the manifestations of the psychological adaptation involved that caused this feature to be favored by direct selection and to therefore become an evolved adaptation. By-products are common in all categories of phenotypic traits, not just psychological and behavioral traits (Andrews et al. 2002; Thornhill and Gangestad 2008). By-products are as evolutionary as evolved adaptations; the existence of both is caused ultimately by—that is, they exist as a result of—selection’s action in the past.

An example of a value-based behavior that is a by-product is the handling of venomous snakes or the drinking of poison as part of religious services in certain Christian groups (Hood and Williamson 2008). There was no direct selection for these behaviors or the very immediate cognitive framework causing them. Indeed, there was past direct selection for avoiding venomous snakes and reducing toxin intake. The psychological adaptation that proximately causes these two religious behaviors, we propose, is functionally designed by past selection to locate and adopt ideas, values, and behaviors that allow the ideologue to honestly signal in-group commitment, allegiance, and boundary (Chap. 9). The same interpretation applies to religious ritual in general. The rituals that are used as in-group commitment displays change periodically in order for members of a group, or members of a budding subgroup, to best exhibit their in-group identity, embeddedness, and boundary. Another example of a by-product value is the preference typical of southerners to drawl the vowel in “dog” as “daaaa … wg.” This preference, we hypothesize, is an incidental effect of human-typical linguistic adaptation that functions in signaling in-group affiliation—as is the pronunciation of dog without vowel drawl.

Our point is that there was no direct selection that favored individuals who handled venomous serpents, drank poison, or drawled vowels. These behaviors and related values are incidental effects of directly selected psychological adaptation for acquiring honest signals of in-group affiliation and commitment. These incidental effects are functional, but that in no way makes them evolved adaptations. By-products, which, by definition, are indirectly selected as a result of direct selection for the adaptation that accounts for them, can be functional or not, and currently adaptive, maladaptive, or neutral. Most of the cultural variation in values and associated behavior of people is by-product (also Chap. 3).

Andrews et al. (2002) apply the label “exapted learning mechanisms” to by-product psychological mechanisms that become functional as a result of change or novelty in the cultural environment. As examples, they mention the learned abilities of driving a car and reading. Both of these by-products arise from adaptation for purposes other than driving or reading, because these two tasks are evolutionarily novel and hence there cannot be adaptation designed to accomplish them. Similarly, the handling of venomous snakes, drinking poison, and drawling vowels are also behavioral outputs of exapted learning mechanisms and are socially functional in the local cultural milieu in which they are typical.

2.8 Units of Selection and Altruism

A basic finding of evolutionary biology, and the research result most fundamental to understanding all living organisms including people, is that Darwinian selection acts most effectively at the individual level to bring about evolution, not at higher levels in the hierarchy of life such as populations, societies, and species. This was the scientific conclusion within evolutionary biology by the 1970s (see Trivers 1985).

We emphasize that this conclusion is not just our opinion or merely a popular opinion in biology unsubstantiated by strong evidence. For example, the discoverers of the basic ideas behind it were given the prestigious Crafoord Prize, a Nobel-like prize that is awarded in the sciences including biology and recognizes science’s biggest or most encompassing ideas. William D. Hamilton won this prize in 1993, George Williams and John Maynard Smith in 1999, and Robert Trivers’ in 2007. The ideas behind these awards were published in the 1960s and 1970s. Of course, the masses of biologists who tested and empirically supported these ideas and continue to do so figure centrally, too, in biology’s conclusion about the relative effectiveness of selection at different levels of life’s hierarchical organization.

Darwinian selection is the nonrandom differential reproduction of entities. Thus, it can act at all levels in life’s hierarchy because each level consists of entities with trait variation among them that can result in their differential survival and reproduction. For example, some species multiply (speciate) more frequently than others or others may not persist phylogenetically in the Tree of Life. Also, some human cultures persist and give rise to “offspring” cultures, whereas others do not. When such differentials are caused by trait differences, the differential reproduction is Darwinian selection by definition. When the differential is the result of chance (randomness), rather than trait differences, the process by definition is drift. Individual selection is differential reproduction of individuals resulting from their trait differences.

Individual selection’s power in causing evolution, relative to the weak selection processes at higher levels, is derived from two facts. First, individuals are far more common than groups (e.g., populations or human societies), providing more variation among individuals than among groups for selection to act upon. Second, individuals turn over far more quickly—possess a higher rate of reproduction and mortality—than groups. These and other well-established facts—e.g., there is higher intergeneration resemblance in individual traits than in group traits—account for why individual organisms are designed to strive in their own reproductive interests rather than the interests of their group as a whole, and why there is a total absence of evidence for evolved adaptation of organisms that has the evolved function of group benefit at the expense of individual reproductive success.

The view that individual organisms are functionally designed for—i.e., have adaptation for—the good of the group (e.g., population, culture, or species) assumes an evolutionary history of more effective group selection than individual selection. This is because the two levels of selection act on altruism in opposing directions: group selection favors group-benefiting altruism that has a net cost to individual reproductive success, but individual selection always acts against such. Individual selection “wins” because of its much greater power in driving evolution.

The conditions needed in nature for group selection to exceed individual selection in power seem to be outside natural reality and possibility (e.g., Williams 1966; Lewontin 1970; Dawkins 1976; Trivers 1985). The conditions of groups turning over more rapidly than individuals and of group number exceeding individual number are not features of the structure of populations, including those of people. In essence, group selection as a cause of evolution (allele frequency changes) could exceed individual selection as a cause of evolution any time selection on individuals within groups does not exist. This circumstance’s occurrence, however, is impossible in nature. It is not surprising, then, that there is no evidence for adaptations of individuals that are functionally organized for group welfare. Of course, group welfare sometimes results from evolved adaptation possessed by individuals, both behavioral and other evolved adaptation, and when this occurs, the group benefit is always a by-product, incidental to the reason the adaptation was favored by individual selection. Differences among groups (cultures) in by-product group welfare may lead to intergroup selection—i.e., differential survival and reproduction among groups due to their trait differences—but it does not follow that this intergroup selection will create group-selected evolved adaptations.

The published literature claiming the inordinate power of group selection and even that the human psychological features that account for culture are group-benefiting adaptations is substantial (reviewed recently by West et al. 2011). Although that literature sometimes gives lip service to the fundamental flaws in the group-selection arguments mentioned earlier, it characteristically lacks serious consideration of these flaws and of the empirical evidence showing the absence of group-selected adaptation. It just proceeds as if human behavior and culture can be productively researched from the viewpoint that effective group selection for group-benefiting altruism created significant features of human social behavior.

We hypothesize that the remarkable tenacity of the group-selection paradigm in the study of human culture reflects a collectivist value in those who advocate it. To the collectivist, things are understood in terms of how they bear on group harmony and well-being. If our hypothesis is supported in future research, it will be a good example of how personal values of people give intuitive, commonsense perspectives that are fundamentally flawed theoretically and empirically. We certainly recognize however that values of group welfare can arise from liberal values because of the importance of the well-being of strangers, even those in future generations. Hence the tenacity of the group-selection paradigm may be mediated by values from either ideological pole alone or by values from both poles.

Some critical commentators may suggest that our opinion that the best theory is differential reproductive success of individuals simply reflects our personal individualistic values. Baschetti (2007a, b) argues this in reply to the widespread negativism among biologists toward any role for group selection in creating phenotypic features of organisms. Baschetti (2007a, b) attributes this negativism simply to Western individualistic ideology and its corresponding anticollectivist ideology. Refuting Baschetti’s view of why biologists prioritize individual-level natural selection as ultimate causation are the quality of the theory and the associated vast evidence supporting our favored scientific view of people and other organisms (e.g., see Abbot et al. 2011; West et al. 2011).

2.9 Individually Selected Altruism

The absence of evidence of evolved adaptation of individuals that is functionally designed for group benefit contrasts sharply with the universality of altruism adaptations of individuals that have been produced by individual selection. Risks taken in benefit of and resources given to offspring by parents (parental nepotism) are characteristic of parents across all species of plants and animals. Risks taken for and resources given to nondescendant kin, so-called extra-parental nepotism, also are common forms of altruism across many taxa of animals. Parental nepotism and extra-parental nepotism show functional organization. To understand the evolution of these types of altruism requires the realization that individuals reproduce—i.e., propagate their alleles across generations—by producing and taking care of offspring and sometimes other descendant kin (grandchildren), as well as by assisting their nondescendant kin. Assisting the reproduction of full- and half-siblings, nieces/nephews, and first or more distant cousins provides avenues of individual reproductive success as assuredly as having one’s own children and investing in them.

That realization, first published by William D. Hamilton (1964), revolutionized biology’s concept of fitness. Darwinian or classical fitness is an individual’s design for direct reproductive success through production and aid of descendant kin (offspring typically, but in humans grand-offspring commonly as well). Hamiltonian fitness, or so-called inclusive fitness, is an individual’s design for direct reproductive success (classical fitness) plus the individual’s design for indirect reproductive success arising from the enhanced reproduction of nondescendant kin as a result of its extra-parental nepotism. Hamilton’s inclusive-fitness theory is just that—a scientific theory—or more exactly, a major theory of evolutionary biology. Its three major predictions are: kin will be assisted more than nonkin, close kin will be assisted more than distant kin, and kin of high reproductive potential within a category of kin (e.g., full siblings) will receive more nepotism than kin of low reproductive potential in the same category. These three predictions are strongly supported empirically and have led to thousands of supportive studies of the social behavior of nonhuman animals and hundreds of such studies of humans (see Abbot et al. 2011; Bourke 2011; West et al. 2011). Fundamentally, an individual’s inclusive fitness determines whether it is favored by Darwinian selection.

Reciprocity among nonrelatives, in which humans in particular engage commonly, is also a product of individual-level selection. Robert Trivers (1971) first proposed this important idea. It is straightforward: if altruists get return goods and/or services from nonrelatives that boost the altruists’ reproductive success (inclusive reproductive success) above the costs to the altruists’ reproductive success of giving altruism to the nonrelatives, then helping nonrelatives will be favored by individual selection. Trivers’ idea about the evolution of social life, like Hamilton’s, has been heuristic, generating a huge literature and receiving strong support as a basic part of the design of human social psychology.

After the seminal ideas of Hamilton and Trivers, significant extensions of the evolutionary theory of altruism were recognized: the concepts of indirect reciprocity, competitive altruism, and altruistic punishment. These three topics are related integrally to Trivers’ ideas on reciprocity and are often features of nepotistic social networks as well.

Adaptive indirect reciprocity occurs when an altruist receives return altruistic benefits that promote its reproductive success from individuals other than the individual(s) to whom the altruist gives benefit. Onlookers of altruistic acts return the benefits instead of the recipient(s) of the altruism. The onlookers need not actually observe the altruistic behavior; they may selectively direct their altruism based on the reputation of others: giving altruism to those with a reputation for generosity and withholding altruism when reputational information implies an unwillingness to assist others. A reputation for altruism serves as an honest and community-based label of one’s worth as a reliable and giving social partner. In human evolutionary history, altruistic reputation affected the quality and quantity of reciprocal alliances one achieved, and thereby affected individual reproductive success. Indirect reciprocity is the basis of the great effort people place in building and maintaining reputations of kindness and helpfulness, as first explained in evolutionary terms by Richard Alexander (1987).

Given the importance of reciprocity in humans, individuals have been designed by evolutionary selection to display their altruism to others. These displays are socially competitive for the altruistic benefits of others that can be received by way of altruistic alliances. Competitive altruistic displays may involve direct acts of altruism by competitors or competition using reputational building.

Altruistic punishment is punitive actions against group members who do not follow normative group behavior. The altruistic punishers suffer costs by engaging in the punishment, while other group members gain when the punishment results in norm conformity. Altruistic punishers obtain their gains through a reputation of being competent social partners, because of their convictions about and knowledge of the norms and goals of their group (see also Pedersen et al. 2013). Indirect reciprocity, competitive altruism, and altruistic punishment are important components of human moral or ideological systems (Alexander 1987).

2.10 A Role for Parasites

We have proposed that parasite stress was a major selective force that shaped the condition-dependent human psychological adaptations that regulate nepotistic behavior, both its intensity as well as its extensiveness outside the nuclear family (Fincher and Thornhill 2012). Extended nepotism is important for creating the reliable social network of kin that reduces individuals’ morbidity and mortality under high parasite adversity. Under low parasite stress, nepotism is more restricted and may involve only the nuclear family. When the human family organization is based on intensive nepotism of extended family members, it is referred to as “cooperative breeding,” because extended family members assist breeding pairs by serving as helpers at the nest, thereby enhancing the helpers’ inclusive reproductive success (Hrdy 2009; Kramer 2010; Jones 2011). We hypothesized that parasite-stress variation may be the selective history for the variable family structures seen across nonhuman animals that range from nuclear family only, to small groups of helpers in cooperative breeding efforts, to extreme eusociality with sterile worker castes as in ants and termites (Fincher and Thornhill 2012). Also, variable parasite stress may account for important aspects of the design of human psychological adaptations that regulate reciprocity among nonrelatives (Thornhill et al. 2009). We discuss infectious disease in relation to nepotism, reciprocity, and family organizations more completely in Chap. 5.

2.11 The Ontogeny of Culture

Proximate causes produce their effects during an individual’s lifetime, including during its development or what biologists call, its ontogeny. An individual’s ontogeny is ongoing from the time of conception to old age and death. Oftentimes, organisms’ features are caused developmentally during a distinct window—or windows—of ontogeny. An example is the pubertal feminization of women’s faces and bodies by estrogen (Thornhill and Gangestad 2008). Other examples are the learning of language and sibling incest avoidance by socialization during childhood. Sibling incest avoidance is caused (proximately) by social interactions of children during childhood (Lieberman et al. 2003, 2007; Lieberman 2009; DeBruine et al. 2011). Hence, language and sibling incest avoidance are socially learned—learned by interaction with conspecifics or members of the same species.

Learning is an ontogenetic event. It is defined typically as the acquisition of cognition and behavior as a result of ontogenetic experiences. All ontogenetic causes of all traits are experienced as the individual develops. Nonlearned phenotypic traits—e.g., the human nose—are caused by ontogenetic experiences that do not bring about subsequent cognition and behavior. Social learning is learning in which a causal ontogenetic experience is conspecific interactions. Such interactions may or may not involve the transmission of information between individuals by teaching or imitation. Sibling incest avoidance is socially learned but does not require imitation and teaching—mere co-socialization during ontogeny can cause it (Lieberman et al. 2003). The acquisition of language and dialect, however, includes social learning by imitation and teaching alongside co-socialization (Nettle 1999).

In people, social learning begins in childhood and continues throughout life. Social learning during ontogeny is a major way humans acquire the values that are optimal for navigation in the local culture. The interactions with conspecifics that proximately cause enculturation give rise to vertical transmission of values/preferences of individuals between generations (by way of genetic relatives or nonrelated individuals) and horizontal transmission between individuals of the same generation (Boyd and Richerson 1985). Both avenues of transmission include psychological adaptations of teaching, differential attention, imitation and anti-imitation, and sometimes of manipulation or coercion. Paying attention to, copying, learning from, and emulation of those people with status, prestige, popularity, skills, knowledge, intelligent action, desirable social networks, health, and physical attractiveness are psychological mechanisms natural selection should have favored directly during human evolutionary history. A reproductive advantage of copying socially successful and high-phenotypic-quality others is that it avoids the costs of time and error inherent in trial-and-error learning. Selection is expected to have favored accurate assessment of models to pay attention to and emulate. Similarly, selection will have favored directly psychological adaptation for anti-imitation of those people without traits and resources that ancestrally promoted reproductive success. Moreover, selection should have favored directly psychological adaptation for identifying and avoiding manipulation and coercion, and for making the best of it, in terms of enhanced reproductive success, when manipulation or coercion occurs in the context of cultural item choice (for more discussion of ancestrally adaptive biases in social learning, see Daly 1982; Flinn and Alexander 1982; Boyd and Richerson 1985, 1996; Henrich and Henrich 2007, 2010; Chudek et al. 2012).

Trial-and-error learning, despite its costs, is a component of the social learning of values that complements copying those with social success and high phenotypic quality. A person’s values when manifested in behavior result in responses from others. Modification of one’s values based on how one is treated by others is promoted by self-awareness. Alexander (1989, 1990) has hypothesized that self-awareness is the component of human consciousness that is functionally designed to provide information about how others perceive one’s actions, thereby allowing adaptive modification based on social feedback. Copying the values of successful models, combined with modifications based on use of those values and resultant social feedback, allow one to develop and maintain a repertoire of values that is socially effective locally. Every social interaction is a scenario for trial-and error learning of more effective values for local social navigation. Moreover, as Alexander (1989, 1990) has explained, people expend great effort in participating as self-aware players in imaginary alternative social scenarios that provide practice of how others will respond.

Another route to cultural learning of values is by way of ontogenetic experiences with environmental features other than people. In this case, because interactions with conspecifics are not causal, this route of cultural acquisition is not social learning. This second route, however, is often influenced by conspecific interactions. Experiences with food types during ontogeny affect the culinary cultural values acquired by people, but which foods taste good versus bad depend, in part, upon their being offered by people and how people feel about and behave toward them locally (Siegal et al. 2011). And fear of spiders and snakes arises ontogenetically in a person, in part, due to social learning: when other people react cautiously or defensively toward these animals (Ohman and Mineka 2001).

The parasite-stress theory of values led us to hypothesize that personally optimal values for avoidance and management of infectious diseases arise ontogenetically, in part, from an individual’s experiences with his or her own immune system’s reaction to local parasitic adversity (Thornhill et al. 2009). Hence, high and enduring activation of the immune system evokes conservative values, and low activation evokes liberal values. This aspect of value learning is not socially learned—not affected by conspecific interaction—but instead is caused by one’s experience with its own immune system.

We expect, however, that various types of socially acquired information will interact with immune-system information to evoke values for dealing with local parasite adversity. This social input will include awareness of local people with debilitations, bodily markers of trauma, developmental irregularities and other bodily deviations from local typicality, as well as folklore and stories about local disease risks.

The term culture is applied to both individual- and group-level features. Learning through social interactions that often includes trial and error as well as learning through nonsocial experiences gives rise to a person’s cultural values and behavior. At the group level, culture is the collection of learned values and associated behaviors of a people at a place and time and the related artifacts and institutions such as stories, recipes, schools, agriculture, hand sanitizer, septic tanks, public goods and services, government, law, and so on.

Social learning, ultimately speaking, is phylogenetically ancient, and much older than the ancestral species of the Primates. The scientific study of the positive bias in acquisition of behavior by copying socially successful and high quality individuals and antimimicking socially unsuccessful and low quality individuals is a huge area of cross-species research. Even some fish and birds are cultural strategists in this sense (see useful reviews by Dugatkin 2000; Seppänen et al. 2011). The elaborate human capacities for cultural learning phylogenetically debuted in the branch of the Tree of Life culminating in Homo sapiens. Also, ultimately speaking, the evolutionary function of human cultural learning—the reason it was directly favored by selection—is the acquisition of information about the local culture that maximized the learner’s survival and, most importantly for the action of the creative Darwinian selection involved, maximized inclusive reproductive success in human evolutionary history.

Enculturation of the individual is an active ontogenetic process of choice of information from the environment that yields reproductive competence in the local culture. Hence, as discussed in Chap. 1, enculturation is not based on passive processes that generate automatic cultural transmission. Although the passive view is assumed widely, its fundamental error is in not recognizing how natural selection will have acted during the evolution of the psychological adaptations involved in the ontogeny of culture. Selection was always against arbitrary learning and automatically accepting into one’s cultural repertoire all that others model or tell one to use. Selection was always for psychological features that discriminate among cultural items and acquire those that result in the highest inclusive reproductive success of individuals. The conjecture that people acquire their culture passively sometimes is a part of the empirically unsupported notion that culture is transmitted by a nonmaterial process that works independently of the action of evolved strategic human brains. The view that enculturation is a passive process derives, in part, from human reasoning that fails to recognize or understand that much or most of cultural acquisition is caused entirely by unconscious information processing, cognition, and deduction. If the parasite-stress theory applied to cultural acquisition is correct, the implication is that the cultural repertoires of people are caused importantly by ontogenetic, unconscious experiences with local infectious diseases and their effects on people. That most causation of values is outside consciousness, as we emphasized earlier in this chapter, is one reason why thinking unaccompanied by empirical support cannot provide knowledge of the causes of values, whereas the scientific method does.

We are proposing that the ontogeny of people is designed to choose ideas, ways of thinking, and attitudes—i.e., choose values—that promoted effective and ancestrally adaptive social navigation in the local culture. The recognition that values are chosen by individuals is quite old in the sociological and psychological literature (see Jost et al. 2009). We add to this traditional sociological view by our general theory of values that claims that the choices are by evolved design—that is, they are guided by psychological adaptations dedicated to the function of value acquisition to meet ecological adversity and demands pertaining to infectious-disease stress, and that much of the choice is unconscious by design.

2.12 Current Adaptiveness

It is essential to realize that there is no implication here that contemporary culture anywhere or everywhere is currently adaptive, i.e., currently promotes net inclusive reproductive success of individuals. The truism is that culture-acquisition adaptations promoted net inclusive reproductive success of individuals in the environments in which the adaptations were favored by selection. Current circumstances faced by humans (and other organisms) can be evolutionarily novel—meaning that the circumstances are not the same as those in which adaptations were favored by selection—which can lead to maladaptive or adaptively neutral traits, including cultural traits.

Evolutionary novelty is common. Humans have aesthetic adaptations that guide them to prefer social partners with facial and bodily features that corresponded to sound phenotypic condition in evolutionary history (developmental health, hormonal health, and limited senescence) (Thornhill and Gangestad 2008). This does not mean that attractive people now and everywhere are expected to have more children than unattractive people—in much of the world, a multitude of evolutionary novel factors such as hormonal birth control, healthcare, and cosmetic surgery disrupt the ancient, consistent, positive correlation between good looks and reproductive success. Humans, too, have gustatory aesthetic adaptations that motivate them to eat foods with high sugar and fat contents. This does not mean that evolutionary biology predicts a positive correlation between junk food consumption and reproductive success; in this case, a negative correlation is expected because of the novelty of copious sugar and fats in Western modern diets—indeed, negative health effects from overconsuming these food items are significant health concerns. The same goes for values or morals. We argue that people have aesthetic adaptation for acquiring certain values because that acquisition was adaptive historically, whether it is currently.

Evolutionary biologists use what is called adaptationism as a method to discover how organisms are functionally designed—that is, to discover their evolved adaptations. Any given evolved adaptation may be adaptive currently, or not. Current adaptiveness of an evolved adaptation is expected when organisms live in the same environment as that in which the adaptation was created by direct selection in the past. We deal more with the adaptationist method below, but first we treat some additional aspects of ontogeny.

2.13 Genes, Environment, and Ontogeny

An evidence-based truth is that each and every feature of individual living things arises during development through gene–environment interactions. This is one of two basic conclusions of developmental biology. Genes are causal in ontogeny and so is the environment. This is the case for each and every trait of the individual, e.g., one’s thumbnail, skin color, and values. This does not imply that the specific genetic loci are known for these traits. For most features, the genetic loci are not known; nevertheless, the genes have to be there for each and every trait of the individual to exist. Modern biology is not genetically deterministic; it does not give more developmental power to genes than to environment. Developmental biology has adopted, on the basis of empirical evidence, a position of total democracy or equality for the creative or causal power of genes and environment during ontogeny, because these two categories of causation are partial causes. This means that each is necessary and neither alone is sufficient to yield a phenotypic feature, e.g., one’s ear or value system. All proximate causes are partial causes. A cause of a phenotypic feature is that, without which, the feature will not occur. Hence, all proximate causes of the feature are necessary to create it, but individually each cause is inadequate. Similarly, each of the two categories of ultimate causation—phylogenetic origin events and maintenance processes—is a partial cause.

The second basic conclusion of developmental biology is that ontogeny itself is an evolved outcome, just as are the phenotypic products of ontogeny. The developmental pathway that creates the human five-fingered hand is evolved adaptation, just as the hand is. Of course, ontogenetic adaptations give rise to by-products, just as the end-product adaptations of ontogeny do.

As mentioned earlier, the parasite-stress theory of human values proposes that environmental developmental causes in the form of encounters with infectious diseases and related information lead to value systems that are suitable for the local disease ecology. These environmental causes of ideology, whether external disease threat or internal immune activation, are ancestral ontogenetic cues. The value-acquisition psychological adaptations of a human use these developmental cues to adopt the values appropriate for the local disease ecology.

Individual differences in values seem to be due largely to environmental differences experienced—specifically, the individual’s experiences with infectious disease and other ancestral cues of contagion risk—rather than genetic differences. We emphasize, however, that individual and group differences in values may be affected by genetic differences—for example, genetic differences in immunity to infectious diseases or in the capability to socially manage the effects of novel infectious diseases. We discuss in more detail the topic of genetic differences in values in Chap. 3. Note that here we are referring to differences between individuals or groups. The question of whether genes or environment is more important can be asked scientifically only in reference to individual or group differences in a feature, but certainly not, as we explained, for any trait of the individual. By group differences, we mean differences between human societies or cultures, or even between subcultures such as castes or social strata within a single society.

A person’s values are caused by contemporary environmental events as well as by environmental experiences during the person’s ontogeny. An example of a relevant contemporary event is when people become immediately more ethnocentric and xenophobic—that is, more conservative—when presented with cues of high infectious-disease salience in their local environment (Faulkner et al. 2004; Navarrete and Fessler 2006). Such cues, in addition to other cues that affect the ontogeny of values as well as the psychological adaptation that reads all these cues and transforms them into values, are proximate causes of values. Proximately, then, a person’s values reflect genetic and environmental causes as well as the psychological machinery that interprets ancestral cues of infectious-disease prevalence in the local environment and guides appropriate values’ acquisition.

2.14 Human Values Are Not an Objectively Delimited Category

An objective definition of values is not possible or necessary. Human values are a category of human preferences, but not an objectively delimited one. Organisms are comprised of a vast multitude of preferences. Indeed, all adaptations are aesthetic or value adaptations, because they interact with the environment, external or internal, and prefer certain outcomes to others. A habitat-aesthetic adaptation designed to bias entry into a productive habitat rather than an unproductive one is no more or less a value or aesthetic adaptation than a physiological adaptation designed to achieve a certain body temperature.

Some scholars have suggested to us that human values correspond specifically to those preferences that really matter to people. But, of course, maintenance of body temperature really matters too, and deviations from the preferred body temperature motivate corrective behavior. There is a great deal of specialized physiological machinery and behavior dedicated to body temperature maintenance. The concept of human values is arbitrarily bounded, too, if one were to claim that human values are the preferences that matter to the human mind. Temperature regulation is physiological, but the mind is part of the brain, a physiological system containing functionally dedicated psychological mechanisms for temperature control.

Living things are those things in nature that are subject to evolution by Darwinian selection. They possess three combined characteristics that make them inevitably and continuously subject to evolution by selection: variation in traits, reproduction, and inheritance (like begets like). All living things, from viruses to petunias and people, have the same fundamental preference or value: they all give the highest valuation to inclusive reproductive success. The preferences and associated goals for which they strive serve that fundamental value. They all owe this homologous similarity in their value systems to direct selection for it in evolutionary history. The value of advancing reproductive success arose with the first life form that possessed all three characteristics—variation, reproduction, and inheritance—and persisted in all branches of the Tree of Life.

Although there is no way to objectively delimit the domain of aesthetics in general or of the sorts of things people refer to as values in particular, there is utility in treating scientifically the topics that have been researched and discussed by scholars of values. Hence, topics included in our book are sexual attitudes and mate choice, political values, personality, religiosity and secularism, parenting and family life in general, prejudice, liberalism, conservatism, egalitarianism, gender relations, authoritarianism, self-concept, provincialism, philopatry, and many others.

There is a debate in the social science literature about what the word “ideology” means (see review in Jost et al. 2009). This literature has been produced primarily by evolutionarily uninformed social and behavioral scientists. Adding Darwinism does not provide an objectively delimited definition of ideology, but does put ideology in the general domain of evolved preferences of people, and hence gives it conceptual unity with the theory of life, evolution. Ideology generally means the composite of ideas reflecting the social needs and aspirations of an individual or group. Thus, a person’s ideology is a significant component of her or his social strategy or means of social navigation, including presentation of self, pursuing status, and accessing social groups and family resources, friends, and mates. We use ideology, beliefs, values, morals, and ethos synonymously because they all refer to preferences in the same conceptual evolutionary framework. Synonymy of these preference labels is often followed in the traditional literature dealing with human values (e.g., Jost et al. 2003, 2009).

2.15 Adaptationism and Special-Purpose Adaptation

Adaptationism is the method of evolutionary biology that identifies adaptations by documenting functional design, and thereby distinguishing adaptations from by-products of adaptations. Evidence of functional design is obtained by observations, including those resulting from experimentation, of a traits’ ability to solve an adaptive problem, and hence a problem that gave rise to differential reproductive success of individuals. Functional design is a property of the individual. It is seen when there is a fit or a correspondence between a phenotypic trait of the individual and an adaptive problem such that the fit solves the problem. Such evidence demonstrates evolved adaptation. This evidence simultaneously provides the necessary and sufficient evidence demonstrating the designer of the adaptation—that is, the type of direct Darwinian selection that acted in the past to create the adaptation. Selection is the only cause of evolution that produces evolved adaptation (meaning that drift, e.g., cannot). The specific type of selection that caused a given adaptation is stamped in the adaptation’s functional design.

And importantly, direct selection favors special-purpose adaptations because the adverse ecological problems that give rise to selection are specific problems. For instance, the human digestive system is for digestion of foods that comprise the omnivorous human diet. This is an accurate, but superficial, description of the system’s functional design. Actually, it is comprised of many highly specialized adaptations, each dedicated to digest a type of sugar but not another, a type of fat but not another, and so on. This specialization is characteristic of the design of adaptations in general, including psychological ones. The human eye is a psychological adaptation whose function is vision, but the experience of vision is accomplished by a multitude of more specialized psychological adaptations (color assessment, distance of object, object orientation, and so on).

Our hypothesis discussed earlier about how people obtain their culture, and specifically their values, is part of a broader, earlier adaptationist hypothesis (Thornhill 1998, 2003). The more encompassing hypothesis is that aesthetic judgments arise out of numerous, specialized psychological adaptations, each organized to give outputs functionally dedicated to solving domain-specific problems of aesthetic assessment. Accordingly, there are distinct specialized aesthetic psychological adaptations for solving habitat selection, mate selection, values selection, and so on across all domains of aesthetic valuation. A great deal is known about the many psychological aesthetic adaptations that show specialized function in people’s long-term and short-term mate choices and romantic lives (Buss 2003; Thornhill and Gangestad 2008). Increasingly, as this book documents, more and more is being discovered about the special-purpose design of human psychological adaptations that assess, adopt, and use values in other categories of human life.

2.16 Beauty as Truth

Although the early aesthetic-philosophers’ notion that the values that make one feel good—the beautiful ideas—identify objectively moral truth or correctness is naturalistic-fallacy nonsense, in certain ways, beauty is actually truth. The signaling adaptations of animals and plants, from the rooster’s comb, the Habernaria orchid’s flower, to women’s facial and bodily estrogenization, are truthful indicators of phenotypic quality (see Thornhill and Gangestad 2008). They are honest signals of the degree of that quality. Beautiful expressions of these signals are truth, and so are the ugly expressions.

Values are truthful in the sense that ideological truth is attributed to a preference when it is understood by the person’s evolved brain as providing a path to relatively high reproduction in evolutionarily historical environments. To use the word “understood” in this context does not mean conscious comprehension, but instead a comprehension inherent in the way the values-adopter psychological adaptation works, or from its functional design. The idea that spirits created people is scientifically unsupported and hence is not scientific truth, but it is the ideological truth of most people who live and have lived on Earth. Aesthetic judgments of ideas by the values-adopter adaptation are based importantly on the data one gathers from positive and negative trial-and-error experiences that arise from holding and manifesting beliefs and from observation of the social successes and failures of others with various beliefs. These largely unconsciously processed data of social experience from childhood forward make truthful or self-evident to the theist the spiritual origin and guidance of people. Similarly, the data of social experience makes truthful to the liberal the equality of people, which is displayed in the liberal rhetoric of the Declaration of Independence of the United States: a self-evident truth is that all men are equal. Each value system has its own self-evident truths.

2.17 Comparative Methodology

A primary unit of analysis used in this book to study variation in human values across the world is that of a geopolitical region. In most cases, these regions are countries. In some cases, the regions are geographically separate colonies or territories (e.g., Guam), or culturally distinct regions within a country (e.g., Hong Kong). The term “country” or “nation” hereafter will refer to all such units of analysis. Although political borders that divide countries do not always correspond to cultural borders, evidence exists that countries serve as useful proxies for societal cultures. For example, Schwartz (2004) showed that there can be much more variation in values among countries than within countries. Also, country boundaries typically are political boundaries, i.e., ideological boundaries, and hence are the logical units of analysis in our research on the diversity of value systems and related topics. Sample sizes of number of countries vary across the international analyses in our book, but we used all available data for each analysis.

Many of our tests in the empirical chapters use both international analyses and analyses across states of the USA. This allows us to examine patterns in data bearing on our hypotheses at two levels of geographical variation. Even within the single country of the USA, there is considerable interstate variation in variables relevant to testing the parasite-stress theory of values.

Our use of countries and US states as sampling units assumes that they are statistically independent. It is critical to discuss and defend this assumption early in the book because throughout the book we employ comparative analyses that assume statistical independence of cultures across regions. Below we give a condensed defense of the assumption that coincides closely with arguments we present in more detail in our recent paper in Evolutionary Biology (Thornhill and Fincher 2013). As we explain, the fundamental reason for the independence of cultures is that psychological adaptations for enculturation are designed to incorporate values and other cultural items that solve local problems of adversity impacting individuals.

In the field of comparative research across cultures, which examines covariation between cultural traits or between cultural traits and ecological variables, the statistical independence of cultures, including that of countries, is debated (e.g., Mace and Pagel 1994; Rogers and Cashdan 1997; Nettle 2009). The debate centers on the transmission of norms, beliefs, ideas, values, i.e., culture, between societies (intercultural diffusion), including retention of cultural traits when a parent culture gives rise to a descendant culture. Some scholars argue that such transmission events make cultures nonindependent (e.g., Murdock and White 1969; Mace and Pagel 1994). The nonindependence among cultures to which this argument refers often is labeled “Galton’s problem,” because Francis Galton apparently was the first scholar (as early as 1889) to claim that cultures cannot be studied as independent units in cross-cultural research (see Mace and Pagel 1994). For instance, the countries of southern Africa share more historical interactions among themselves through diffusion and common ancestry than shared between cultures of southern Africa and cultures in southeastern Asia. Hence, according to some researchers, southern African countries are not statistically independent, but instead comprise a single observation (Nettle 2009).

This argument goes on to claim that given the nonindependence caused by cultural sharing, researchers should correct for historical cultural sharing by considering as valid units of sampling and analysis only the changes in a cultural feature—the feature’s appearance and/or loss or modification—among a historically related group of cultures (e.g., Mace and Pagel 1994). Hence, according to this claim, what counts is how a cultural feature behaves in terms of arising, disappearing, or changing in relationship to a hypothetical causal variable (e.g., a climatic variable or parasite stress). Mace and Pagel (1994) state that “the validity of comparative methods for anthropology depends upon correctly counting [these] independent instances of cultural change” (p. 551). They define such instances as “any instance of the de novo invention or acquisition of a new [cultural] element by copying from another culture or the change or loss of an element.” They also emphasize, and certainly correctly, that independent instances of cultural change cannot be identified without a phylogeny of the cultures under study. The phylogeny of a group of cultures identifies their historical interrelationships. Hence, this approach is concerned with identifying instances of cultural change, which then become the units of analysis (the sampling units or sample size) in testing for a relationship between two cultural elements or a relationship between a cultural element and an ecological variable such as parasite stress.

This approach sharply contrasts with one based on the assumption that cultures are independent. With the assumption of cultural independence, each of the cultures under investigation, and whether they share common ancestry or cultural items due to diffusion, is a sample unit, and there is no pseudo-replication (i.e., inflation of sample size) by including in analysis all the cultures as the sample size.

The existence of historical sharing among cultures in a region or across regions (e.g., the USA’s cultural sharing with Western Europe), whether by cultural diffusion or common ancestry, is not simultaneously a fact about the nonindependence of the cultures. This is because, as we have explained, cultural transmission processes, whether involving intercultural diffusion, intracultural transmission within or between generations, or common cultural descent, are guided by evolved psychological adaptations that function to selectively invent, adopt, discard, or change cultural features based on local utility of the features for inclusive reproductive success. Moreover, correction for historical cultural influences by determining independent instances of cultural change based on phylogeny, proposed by Mace and Pagel and others, is not a uniformly scientifically superior method for all cross-cultural research and is theoretically inaccurate and empirically misleading for testing cross-cultural hypotheses about the causes of the transmission of cultural elements and the maintenance of cultural differences and similarities.

The argument of cultural nonindependence is simply based on a judgment to give validity, or at least salience, to one scientific question about cultural history, but not another. The question addressed by the nonindependence approach is when and where did a target cultural item(s) change significantly or first arise de novo or become lost from the cultural repertoire. Certainly, these are valid scientific concerns, and ones in which Galton’s problem must be considered. As the cultural nonindependence proponents correctly emphasize, to answer questions of the debut, disappearance or change of a cultural item in history requires knowledge of the phylogeny of cultures involved in the analysis. The other scientific question about cultural history deals with the reason the cultural trait was maintained after it arose. For this question, Galton’s problem is totally irrelevant. Researchers who propose that the origin causation is the important question are favoring one question over the other.

The nonindependence perspective seems to reflect a view of people’s mental design that is quite different from the view of those who assume cultural independence. Is the relevant psychology—that for the assessment, adoption, rejection, and modification of cultural items—the product of past evolution by selection for inclusive reproductive success that acted potently only at the interindividual level, or is it not? One’s answer to this question importantly informs one’s position on cultural independence or nonindependence. Those for cultural independence understand the relevant psychology as we do: individual humans are highly discriminative cultural strategists, because their enculturation is designed by past selection for maximum inclusive fitness.

Daly (1982), Flinn and Alexander (1982), and Daly and Wilson (2010), in criticizing hypotheses that propose cultural transmission with mere exposure to others’ ideas as all that matters—the cultural inertia notion we have criticized and also the similar memes hypothesis—discuss the theoretically, heuristically, and empirically verified strengths of viewing cultural transmission as caused by psychological processes that function to selectively adopt cultural items. Alexander (1979a, b, 1987) and Irons (1979), among others, give overviews of the theory and evidence supporting this view of enculturation. Our book is a testament to the strength of this view as well. Gangestad et al. (2006) focused on evocation of culture—the experiences of people in a cultural ecology that proximately cause their cultural repertoire. Gangestad et al. emphasize also the history of direct Darwinian selection for learning mechanisms that incorporate cultural repertoires that are adaptive (ancestrally) locally. Schaller (2006) explains why this evocation is responsible for the transmission of cultural items. Flinn (1997) applied this view of enculturation to ideas used as competitive tools, as an explanation for the creation or origin of new cultural features and their perpetuation.

Under this way of thinking, cultures are independent because the creation of cultural features and their transmission between individuals within a generation or between generations or between cultures depends on whether the local individuals find attractive the various available values and other cultural items, where attraction is based on evaluation and choice by psychological mechanisms dedicated functionally to this. Hence, transmission, both within and across cultures, is not a given. Instead, it involves very sophisticated preference adaptations dedicated to the assessment and selection of cultural features (just as mate preferences depend on functionally specialized preferences) and to the incorporation of those cultural items that are optimal for that place and generation. In statistics, independence is defined typically as follows: “Two events are independent if the occurrence of one of the events gives no information about whether or not the other event will occur” (Statistics Glossary, www.stats.gla.ac.uk/steps/glossary/probability.html#indepevents). Historically related cultures are statistically independent because knowing the cultural repertoire in one culture does not allow you to conclude automatically that the same repertoire will exist in a closely related culture. If both cultures have the same ecological causes of enculturation then cultural similarities are expected to occur, but if not, they are not. Hence, distinct cultures, as identified in anthropology and cross-cultural psychology, are statistically independent, even if they share a recent history and geographic proximity. With the cultural independence approach to study cultural diversity, the phylogeny of the cultures under investigation is irrelevant.

The ecological variable of primary interest in the parasite-stress theory of culture is parasite stress. Thus, countries that have high parasite prevalence are expected to show similarities in culture (e.g., collectivist values), whether or not the countries are near each other, contiguous, or on separate continents. Likewise, across this range of proximity and distance, countries that have low parasite prevalence are expected to show cultural similarity (e.g., individualist values). According to those with the view of nonindependence among cultures, however, the collectivist countries of the Middle East, for example, share a cultural history and hence are nonindependent, because their culture arose once and then was retained. This claim ignores the cause(s) of the retention and gives importance only to the causation of cultural origin. Understanding retention of values across time and space requires a causal explanation; saying that history accounts for retention is a description of how a culture was in the past but does not address causation. Historical retention of cultural features in a region is never an explanatory substitute for ecological and ultimate causes of temporal consistency in culture. And, as we have emphasized, historical–particularistic explanations based on tradition per se can reduce to a view that quasi-spiritual forces drive cultural retention. The reasoning we advocate provides the causal proximate reason for the retention. Ecologically or proximately, the parasite-stress theory proposes that the retention is due to the continuation of high parasite stress in each of the Middle East countries, and each of these countries is a distinct datum. With this approach, one is spared the difficulties and uncertainties of phylogenetic cultural reconstruction that many have discussed (e.g., Mace and Pagel 1994).

We emphasize, too, that the parasite-stress model of sociality and values specifically offers a hypothesis for the variation in isolation of cultures, or said differently, the variation in intercultural exchange, an important variable and topic in cross-cultural research. For instance, some countries endorse more inflow of immigrants, cultural products, and ideas than others. In the Preface, we mentioned the long-term cultural isolation and parochialism of the Old South (Key 1949; Reed 1972, 1983; Grantham 1994). This cross-cultural variation in isolation or openness is not a variable that confuses independence among regions. Instead, it is the predicted outcome, based on variation in the value systems caused by variation in parasite stress. Openness to new and different people, ideas, and commercial products is prevalent in countries with liberal/individualistic values, whereas collectivist countries are more culturally isolated, parochial, and xenophobic (Chap. 11; Schaller and Murray 2008; Thornhill et al. 2009).

Similarly, the parasite-stress theory of values proposes that promoting innovative thinking or promoting its opposite—adherence to traditional ideas—will be predictable in relation to variation in parasite stress. In collectivist societies innovation is not rewarded and may be discouraged (Chap. 11; Thornhill et al. 2009, 2010). Although this will limit the potential pool of values that arises, it will not affect the values selected locally among those that are available. Also collectivist cultures are more traditional and conformist than individualist cultures (Fincher et al. 2008; Murray et al. 2011). This does not mean, however, that regional history causes the values adopted under collectivism; instead, the values of traditionalism and conformity, which are evoked by high parasite adversity, are the causes, not history.

To attempt to correct for nonindependence due to historical contact, say, by replacing cross-national analyses with ones that examine parasite stress in relation to our focal dependent variables in each of the six world cultural regions identified by Murdock and White (1969), or by giving more credibility to world regions’ analysis, is theoretically inappropriate given the independence of countries’ value systems. Such analyses are empirically incorrect, too, because they greatly reduce sample size and hence the ability to detect actual patterns across the globe. “Correcting” is the wrong word to call the analysis by world regions, or for the other methods for dealing with alleged historical nonindependence that have been proposed by Mace and Pagel (1994), Nettle (2009), and others. Correction implies a more scientifically valuable procedure and hence the word “correction” does not apply in research on cultural diversity such as ours. The correction procedures address a different question (the origin of a cultural trait in a cultural phylogeny) than what we focus on in this book. Our approach is focused on the causation of cultural diversity arising from psychological adaptation that functions to create, retain, discard, or modify cultural elements based on local utility. Hence, we assume cultural independence across geopolitical regions.

As presented by Mace and Pagel (1994) and others, the correction procedures for nonindependence are statistical adjustments, not evolutionary theoretical adjustments. A statistical argument is not the same as an evolutionary theoretical proposal. We provide here a theoretical rationale for the use of the correction procedures. The procedures are theoretically valid when the research question is about independent instances of cultural change, but invalid when the research question is cultural transmission and maintenance.

2.18 A Cultural Phylogenetic Example

An example involving imaginary cultures will illustrate further our view. Figure 2.1 is a phylogeny of nine imaginary cultures showing the relationships between them based on, say, evidence of homology in degree of language similarity. Homology means the degree of similarity among traits compared across kinds (e.g., culture, species, and so on) that is caused by common ancestry, i.e., shared descent from an ancestor with the trait. On the phylogeny, each branch tip is a culture; “yes” refers to camels being used by that culture, and “no” to camels not used. Let’s assume that anthropologists recognize each culture as distinct based on language and norm differences among them. The phylogeny shows that “no camel use” was the ancestral cultural state from which “camel use” was derived. The phylogeny also shows that camel use exists in four cultures, but arose independently only three times in the three lineages with an asterisk .

Fig. 2.1
figure 1

Phylogeny of nine cultures constructed from the degree of language similarity that is due to common descent, asterisk = independent origin of camel use, yes = camel use, no = no camel use (figure originally published in Thornhill and Fincher 2013)

Full size image

Consider the following hypothesis: drought causes people to value camels. Imagine that a study of rainfall data in the regions of the nine cultures shows the following distribution:

 

Cultures with Camels

Cultures without Camels

Drought

4

0

No drought

0

5

The cultural nonindependence scholars (those scholars who insist on a view of cultural interdependence as a mainstay of cross-cultural methodology) say this data distribution cannot be used in testing the hypothesis about cultural history of camel use. They say that the two cultures “yes a” and “yes b” are not two cases, but one, because these cultures are interdependent (nonindependent) historically as a result of camel use arising in their common ancestral culture (existed at →). Certainly, they are correct if their historical question is the independent origins of camel use. Camel use arose three times from no camel use. It always arises with the environmental condition of drought, but you cannot count the four cultures with camel use as four separate data.

As discussed earlier, there are, however, two scientific questions/hypotheses about cultural history. One is the origin of a cultural trait (debut on the tree of cultural history); the other is its persistence (or nonpersistence) after its origin. The two questions are complementary, not alternative, and a complete understanding of the history of a cultural trait requires answering both. Because they are not alternatives, though, only one question can be investigated at a time. Furthermore, it is critical and fundamental for researchers to understand the distinction between analyses of cultural trait origin and analyses of cultural trait persistence.

Our point is that, for the question of cultural persistence (not that of independent-origin events), you count all four “yes” cultures as supporting the hypothesis. The reason: people adopt values or other cultural preferences based on local costs and benefits. People are designed by past selection to assess, adopt, reject, or modify values (and other ideas) just as they are designed to make choices of mates, habitats, and so on. All such choices are based on processing local costs and benefits. Even if culture “yes a” got the camel-use idea from “yes b,” it was adopted and transmitted by “yes a” people as a result of benefits/costs of the idea to them. “Yes a” people in their place and time independently perceived camel use to be valuable, and it persisted. “Yes a” and “Yes b” have the camel use in common (that particular similarity) for one of two reasons: (1) because it was transmitted through time (through generations) from their common cultural ancestral group, including across generations after “yes a” and “yes b” became distinct cultures; or (2) because one of these two obtained it from the other culture. Either way, the persistence of camel use across time—accounting for its persistence in “yes a” and “yes b”—is not a given, but an interesting problem/question about ecological causation of the persistence of camel use.

To the cultural nonindependence scholars, cultural history is only or primarily about the origin of cultural traits. Their focus is required and correct for their question: find the independent origins, which require a phylogeny of the cultural groups, and then map those origins onto a hypothetical causal ecological factor (drought, in the example). Cultural nonindependence is an issue only for reconstructing the origin of a cultural trait; it is a nonissue for questions such as ours about the persistence of cultural values. This argument applies to any regional analysis of cultures, from ethnographic cultures to average values of people in a country or in a state in the USA.

In later chapters, we will examine both cross-national and more focused regional analyses of parasite stress in relation to value systems. In some of the analyses, we look at patterns across Murdock’s six world regions and across census regions within the USA. We do not do this to overcome nonindependence among countries or states; instead, we do it to determine if any regions exhibit exceptional patterns to those we find in overall analyses across nations or across the 50 states of the USA. This allows us to identify and address exceptional regions that may exist despite the overall significant pattern, and when they do exist, additional research questions are raised.

2.19 Interspecies Comparative Research

The methods for historical correction in cross-cultural research used and advocated by Mace and Pagel (1994), Nettle (2009), and others were borrowed from the typical phylogenetic analytical approach used in biology for the comparative study of adaptations and other traits across multiple species. This borrowing assumes that cultures in a geographical region are interdependent in ways analogous to the interdependence of closely related species—in both cases, shared history is thought to generate nonindependence. Biologists widely believe that it is necessary to correct for phylogenetic history when comparing traits of species, and, hence, it would seem to follow that cross-cultural analyses must do the same (Ridley 1983; Brooks and McLennan 1991; Harvey and Pagel 1991; Mace and Pagel 1994). Given the similar conception of how phylogeny creates nonindependence in both cross-cultural analyses and interspecies analyses, it is informative to examine critically the popular method of interspecies analyses that is anchored in the assumption that the features of closely related species are not independent.

As in cross-cultural research, the phylogenetic correction procedure is essential when the research question is about trait origin in a phylogeny, but invalid when the question is about trait maintenance after origin. The view that there is a need for phylogenetic correction in the comparative study of diversity in adaptations and other phenotypic traits was criticized by Williams (1992), Westoby et al. (1995a, b, c) and Reeve and Sherman (2001), but their criticisms have not been widely discussed or appreciated. The flaw in the non-independence–phylogenetic-correction opinion is that related species, given that they are distinct species, are historically evolutionarily independent units, and hence the evolutionary processes, including selection, that occurred in one given lineage (a species) are independent of the evolutionary processes that happened in another lineage (a different species), even when species are in the same genus. This independence is in the evolutionary processes that acted historically in each lineage (each species), and it meets the standard definition of statistical independence mentioned earlier.

Consider an example involving two closely related species preyed upon by the same predator. And, in this example, the prey species evolved functionally identical predator-defense adaptations such as camouflage coloration. Even though the “same” selection (differential reproductive success of individuals as a result of their features of defense against a single species of predator) and the “same” adaptation (in terms of functional design) are involved, the evolutionary processes in the two lineages are independent because the two lineages are distinct species—and hence evolved to the status of distinct species through reproductive isolation.

The conclusion of evolutionary independence is equally warranted if you consider a by-product that is similar in each of these species. The by-product in each lineage was maintained by the direct selection that favored the evolved adaptation in each lineage to which the by-product is tied. The direct selection in this case acted independently in each lineage because they are different species. Hence, all the traits, whether adaptations or by-products and whether similar or dissimilar, of closely related species (and distantly related species) are evolutionarily independent. These traits are statistically independent too: a trait’s presence (or absence) in one species does not predict its presence (or absence) in a closely related species because of lineage-specific causal processes acting to create (or eliminate) the traits.

Research procedures for distinguishing species in biology, whether based on evidence of morphological differences, evidence from reproductive isolation, and/or evidence from the distinctiveness of branch tips in genetic phylogenetic analysis, are efforts to address historical evolutionary independence of lineages. This is the most widely accepted and encompassing criterion for distinguishing biological species (e.g., Coyne and Orr 2004). Of course, the nature of speciation processes necessitates that the degree of evolutionary isolation among closely related species is a continuum. Closely related species will vary in the length of time they have been evolutionarily independent. Species also will vary in that interspecies’ hybridization may or may not occur, and when it does, it varies in degree, persistence, and extent in which it affects traits that are the focus of a particular comparative analysis. This continuum, however, does not cast doubt on our general point that the empirical recognition of evolutionary independent lineages is the criterion for species designation in biology. The concept of species as evolutionarily isolated lineages that have evolved independently and hence have been subjected to lineage-specific evolutionary agents that caused their traits, even their trait similarities, is the virtually universally accepted species’ concept in the life sciences. (See Thornhill and Fincher 2013 for an expanded treatment of phylogenetic methodology used in biological research across taxonomic groups.)

Phylogenetic causation and evolutionary maintenance causation are distinct categories of causation. They are complementary categories and not competitive (alternative) ones. To understand fully the historical causation of any trait, cultural or otherwise, requires knowledge of both causal categories. To base a need to correct for cultural history in an investigation of cultural elements of related cultures on the popular practice in biology of phylogenetic correction is replete with misconceptions. In the final chapter of this book, we discuss our hypothesis that the opinion that cultures are not independent reflects the collectivist cognition of interdependence.

2.20 Opponents of Evolution Applied to Human Behavior

The non-independence-of-cultures researchers we criticize earlier are not opposed to the study of human behavior and psychology using evolutionary theory. Instead, they have different assumptions than us about how certain methods should be applied in this research. This last section of this chapter briefly addresses the actual opposition to applying evolutionary biology to human social behavior and psychology. Many evolutionary biologists have spent time and effort to address these opponents; a sample of comprehensive responses to those who oppose applying evolutionary biology to human behavior can be found in Thornhill and Palmer (2000), Alcock (2001), and Kurzban (2010). The opponents are comprised of two ideological camps: (a) certain theists and (b) certain scholars and media commentators, who either self-identify as liberals or are assumed to be liberals. We find both opposing camps scientifically intriguing.

Some theists have ideological issues with the concept of evolution as a whole, but especially to references of humans as evolved. This is fully understood, given that high religiosity coincides with conservative values (Chap. 9). These values include a priority given to supernatural direction of human activity and associated magical thinking, security based on salvation from punishment and pain in afterlife, and conformity and obedience to traditional contra-evidence interpretations. Some theist critics of evolution as applied to humans have proposed that religion is in a moral war with evolution, claiming that their religion endorses a moral worldview, whereas evolution endorses an immoral worldview. Of course, as we emphasized, the study of evolution is science, and science does not endorse any moral system. Thus, evolution does not and cannot threaten one’s ideology, religious or secular. The war-of-morals criticism is profoundly misinformed, but keeps appearing in the media and from pulpits. Its basis, in part, we hypothesize, is the ideological nonacceptance of the naturalistic fallacy. As we have explained, collectivists cannot comprehend that facts can be interpreted independently of in-group moral goals and harmony. Given the conservative understanding of self as interdependent, the theist opposition to evolutionary biology will continue as long as there are theists. Furthermore, as mentioned in the previous chapter, some theists are accommodationists and thus believe erroneously that the study of religion or morals is off-limits to and not knowable by scientific investigation.

The liberal critics of evolution applied to human behavior are more challenging to understand scientifically. A core value of liberalism is openness to new ideas and ways, including scientific discoveries (Chap. 7). The biologists Richard Lewontin, Steven Rose, and Steven Gould essentially have claimed in their criticisms that evolutionary theory does not apply to human social behavior. The evidence is strongly against their view, to say the least. How could an open, analytical mind discount evolution applied to any part of human psychology and behavior? The evolutionary theoretical ideas and supporting evidence have gotten richer and more encompassing of human affairs at a fast clip. Actually, the evidence has been overwhelmingly supportive ever since biologists solved the issues of human altruism in the 1960s and 1970s. The biologist critics behave more like accommodationists of a different type. They accept evolution applied to human physiology, biochemistry, genes, and bones, but claim that the human mind and behavior are different. The difference they see is that evolution, the general theory of all life, cannot inform, and should not be used to try to inform, these topics; in their writing they have vehemently opposed the reality that human behavior is evolved.

Some of these critics follow and believe Marxist ideology (see Alcock 2001). Marxism is a collectivist ideology in which the group’s goals are all important. People’s duty is to the collective or state over their personal interests. Marxism, too, is a holistic ideology in which the collective cannot be understood by the reductionist analysis that is fundamental to science (Gregor 2009). In Chap. 4 we discuss evidence that holistic reasoning is a component of collectivist cognition. Also linking Marxism to collectivism is the fact that Marxist values are the ideological foundation of totalitarian communism, which is characterized by undemocratic values, including elite control of all economic and political matters, and illegality of personal property rights (Gregor 2009). In Chap. 10, we discuss the evidence showing that highly autocratic governments, like ones based on Marxist totalitarianism, are also ones with high collectivism and associated authoritarianism. Marxism is run-of-the-mill collectivism with communist ideology in place of religious dogmatism.

The so-called liberal critics can appear intellectual to naïve audiences when they raise criticisms such as: those people (like us) who discuss human behavior as evolved think that all traits are evolved adaptations. They say, too, that such people do not pay attention to culture. Of course, a huge, published literature documents that they are profoundly mistaken in both claims. One straightforward and reasonable hypothesis for their opposition is that it, like the theist opposition, stems from collectivist values. Historically, the opposition to science has come essentially entirely from conservative ideologues, while liberals have supported science (Ferris 2010). The opposition of critics in both camps is simply a form of ideological opposition to the most significant scientific understanding of humans ever accomplished. Hence, the so-called liberals who oppose evolutionary biology as applied to people’s behavior may hold significant conservative values. Certainly, it is not scientifically reasonable to accept the public proclamation of held values by a person or group as the truth of held values. For example, autocratic governments sometimes claim to be democracies, and many prejudiced southerners in the Old South claimed to be democrats. This is a reason why political scientists measure democratization and values rather than taking a person’s or a group’s word for what is believed. The values, then, of the self-proclaimed liberals who oppose evolution applied to human behavior is an empirical issue and could be studied by obtaining conservatism-scale-questionnaire responses from samples of people who are supportive of science until it is applied to the evolution of human behavior and psychology. Our prediction is that such people will score right of center and thus be more conservative than liberal. Some research has been conducted already to measure the values of graduate students who do research on evolution and human behavior; they are way left of center (Tybur et al. 2007).

Beyond our scientific fascination with those who ideologically oppose evolution being applied to human behavior is our worry that these people hinder the rate of scientific discovery about the causes of human affairs. Such opponents are not rare in academia, and thus sometimes serve as referees for submitted manuscripts to journals or grant proposals, and as consultants to scientific journals and societies. This gives them considerable influence on the research that is conducted and published. Also, some of these opponents actively publish their own papers and books criticizing the concept of evolution applied to human affairs.

As a recent example, in an article in the prestigious scientific journal Nature, Bolhuis and Wynne (2009) criticized the application of evolutionary ideas to human psychology with the standard, tired, uninformed comments. They say that the “approach overlooks the importance of culture in shaping the human mind” (p. 832). They go on to say that the approach assumes all traits are the product of the direct action of natural selection. They emphasize, however, that some traits are by-products of selection acting on some other trait. Their final and “most serious” objection is that “cognitive traits of past generations leave little trace in the fossil record” (p. 832). Hence, they claim, the human mind cannot be understood scientifically, or only understood at a trivial level.

All of these criticisms are answered in this chapter and have been answered many times in the earlier scientific literature. Scientists who study the evolution of human behavior and psychology pay a great deal of attention to culture and to by-products. The fossil record is not necessary for robust conclusions about the functional organization of evolved psychological adaptations. The full evidence of the past causal selection process involved in the creation of each psychological adaptation (and all other types of adaptations) is stamped in the functional design of the adaptation.

Evolution and human behavior, like any other scientific field, welcomes criticism and advances because of it; however, the ideological opponents of the research on the evolution of human behavior have not used the validated rules of scientific criticism. Valid scientific criticism is based on some objective examination and understanding of the evidence and ideas in the field of research criticized. Objective criticism is promoted by self-knowledge of one’s values and their effects on biasing reasoning. Of course, these critics ignore evidence altogether and/or distort it. They proceed by ideological faith, not by evidence. On scientific grounds, neither of the two groups of critics has had anything to say of scientific interest or relevance. As social commentators, they are maintaining into the twenty-first century the long-standing anti-intellectual tradition that first arose in opposition to the Enlightenment. (For an excellent treatment of the history of the anti-Enlightenment tradition, see Sternhell 2009.)

In the next chapter we give a detailed discussion of the parasite-stress theory of values.

2.21 Summary

This chapter discusses the primary methods and assumptions used throughout the remainder of our book.

The scholarly study of aesthetic judgments, including those about the attractiveness/unattractiveness of values, initially arose as a branch of philosophy. This scholarship failed to advance knowledge of the causes of values and other aesthetic judgments and preferences. Its failure resulted, in part, from its use of the philosophical method of evaluating an idea entirely in terms of emotional verification. The essence of the scientific method is its ability to empirically evaluate conjectures. The scientific method replaced the philosophical method and then became and remains the sole way of knowing the causes of natural things, including the causes of morals. Another reason that the philosophical method cannot provide insight into the causes of values is that common sense or intuitive cognitions are values. Hence, human thoughts in themselves lack scientific objectivity because they are biased toward a particular outcome. An additional reason the philosophical method cannot address the causation of values is that human reasoning and rationalization do not access much of the information actually processed in reaching conclusions.

Darwin’s method of historical science importantly extended the scientific method to causes in the deep-time past. Darwin’s method is the one used for identifying deep-time past causation in all scientific fields that study such causes, including biology.

Biology is the scientific study of the proximate and ultimate causes of all life’s features and hence encompasses totally all the scholarly fields that investigate human activity. These fields vary greatly in scientific sophistication and power because of varying awareness and use of biology’s general theory: evolutionary theory. The parasite-stress theory of values uses this theory, including its applications to social behavior and culture.

People are enculturated during their ontogeny. We propose that people have values-adopter psychological adaptation that is functionally designed to incorporate during ontogeny the values that provide solutions to local problems that adversely influence the reproductive success of individuals. We emphasize the role of this psychology in adopting values that optimize behavior in relation to the level of local infectious diseases. This psychology, like all evolved adaptation, is the product of evolution by individual-level selection for inclusive fitness maximization. The common, but erroneous, view that culture functions for the good of the group, we hypothesize, reflects collectivist cognition and values about the overriding importance of group prosperity.

Some scholars have proposed that cultures are essentially interdependent because of intercultural flow of cultural items and common cultural phylogenetic descent; some researchers see this as an impediment for cross-cultural analysis. The enculturation process we propose counters this, because people adopt cultural items including values based on assessments of the items’ local benefits relative to costs. Hence, it is valid to treat cultures and cultural regions as independent in analyses. The cultural nonindependence view is correct when the question investigated is of the origin of cultural items in a cultural phylogeny, but incorrect when the question is one of the transmission and maintenance of cultural items after their origin.

The scientific study of the evolution of human behavior and psychology continues to advance despite ideological opponents whose striving maintains the anti-Enlightenment tradition that began in the 1700s.