Keywords

1 Introduction

The term “User Experience” (UX) was introduced by Norman [1] to extend the study of human-product interaction beyond the consideration of usability and effectiveness. Scholars attempted to find a shared definition to this concept [2,3,4,5]. Simultaneously, theoretical models on UX have also been developed over time [6, 7]. Ogunyemi et al. [8] reported a strong growth of UX studies in the last decade. Especially with the advent of new technologies, the domain of Human Computer Interaction has been established. Hassenzahl and Tracktinsky [9] noted a shift in focus within the ‘analysis of the study of UX in Human Computer Interaction (HCI). At the beginning contributions focused only on programmatic and task related aspects. Gradually literature on the topic became more conceptual. These articles aimed at a common vision of what characterizes a good UX. These concepts have been applied in empirical studies that involved products with a software and intangible component and, a hardware and tangible component [10, 11]. The former refers to digital products such as Web Apps and digital interfaces; the latter refer to the physical part of the devices (e.g., smartphones, keyboards, and laptops).

Tests and experiments that analyze HCI products are numerous, while empirical studies that examine tangible objects such as consumer goods or engineering products are not likewise widespread or do not rely on adequate research questions [12]. The hardware component can be considered close to the world of consumer goods and engineering products. Thus, it is plausible that methods and tools used to study hardware components could also be suitable for consumer goods and any other product that involves a physical component.

Based on these considerations this work aims at investigating the UX with HCI products characterized by software and/or hardware components. Particularly, objectives, methods, instruments, and typologies of experiences in experimental research have been classified and compared.

The paper is structured as follows. Section 2 provides the selection method applied for the research of contributions, as well as the selection criteria to collect a pertinent sample of papers to be analyzed. Section 3 proposes the classification criteria in detail followed by the resulting table. Section 4 presents the discussions, while Conclusions are drawn in Sect. 5.

2 Methods of Research

To verify the presence of different UX approaches towards software and hardware components in HCI, a sample of convenience of studies should be selected.

The selection of a preliminary reference sample of studies took place by first selecting a pertinent journal of the topic. The “International Journal of Human-Computer Interaction” was considered an authoritative and pertinent source. It was chosen since it addresses, among the others, the cognitive, and ergonomic aspects of interactive computing with a particular attention to human elements related to system and contexts of interaction. The search was performed in Google Scholar, where keywords such as “user experience”, “HCI”, and “case study” have been used to search pertinent papers limited to articles published in the aforementioned journal. The authors considered papers presenting case studies described in contributions published between 2015 and 2021 only. From an initial sample of more than 100 papers those contributions proposing methodologies and theoretical approaches have been neglected. For brevity, only the papers including “User experience” and “case study” in the title or in the abstract have been considered. 15 articles have been collected to form this preliminary sample. This limited number of sources is clearly not exhaustive. It was nevertheless considered sufficient for extrapolating the existence of differences in UX towards hardware and software. The admitted length of the present paper represented a further constraint for the authors.

3 Classification

The articles belonging to the final sample were classified along the dimensions shown in Table 1, which provides an overview of the result of the categorization work. The most relevant classes were identified in an intuitive way upon after reading the selected contribution. The choice of the classes was also supported by other review works carried out within UX and the use of technological systems within design [13, 14]. Accordingly, contributions have been organized based on their year, source, product typology (software of hardware), objectives, methods, instruments involved in the study and typology of UX. The details of each category follow.

  • The “Product” column considers the specific HCI products investigated in each study.

  • HCI products have been categorized into two main groups: Software (“S”) and “Hardware” (“H”). In the table, an “S” was assigned when the case study involved digital products (e.g., Web apps, websites interfaces, pop-up warnings among the others); “H” when physical products (smartphone hardware, tablet hardware, haptics systems components among the others) were analyzed. “S/H” means that both software and hardware components were considered.

  • “Objectives and topic facets” have been expressed readapting the categorization made by Ogunyemi et al. [8] (table 6, p. 13–14,). Since the original categorization was general, the purpose of the adaptation was to focus on the UX domain, including the evaluation of UX and related approaches.

  • “Methods” include to the theoretical approach and methodology used to acquire and collect data. Authors focused on data analysis (quantitative and/or qualitative), environment and experiment setting (natural or controlled or non-specified), and participants involved (final users and/or experts).

  • “Instruments” relate to product representations presented to participants (prototype or end-use product) and the technology involved in data acquisition as support tools, such as biofeedback (biometric measurements tools such as skin conductance (SC), Electroencephalography (EEG), raw electrocardiogram (ECG)), Virtual Reality (VR) and haptics.

  • “Experience” lists the 3 different kinds of experiences identifiable in the design and UX literature; they are Ergonomic, cognitive, and emotional. Ergonomic experiences are related to usability and effectiveness [15]. Cognitive experiences are related to the aesthetic perception of a product [16]. Emotional experiences involve emotions, affective phenomena, feelings, and pleasure [17].

Table 1. Classification UX of HCI products featured by software (“S”) and hardware (“H”) components or both (“S/H”)
Full size table

4 Analysis and Discussions

The main insights from the analysis follow.

In terms of objective of the study, the outcomes confirmed the results highlighted by Ogunyemi [8], in that UX and usability are the main objectives of HCI studies. Usability is predominantly investigated when the software and hardware components are considered separately. UX is studied when these components are evaluated as a whole system.

In terms of analysis approaches, scholars tend to use both quantitative and qualitative data analysis approaches to study HCI products. However, when both software and hardware are considered, qualitative analysis seems to be more leveraged [18,19,20, 25, 32]. This highlights that a complex system needs to be considered in a more comprehensive way. Therefore, objective data only is not sufficient to describe and analyze the different facets of UX.

In terms of experimental environment and technologies used as support tools, there is a predominance of artificial settings and controlled environments in HCI experiments (presented in 8 papers). It is worth noting that natural environments are preferred to study the software components of a device only [21, 22, 28,29,30]. This also reflects the diffuse involvement to involve other devices such as smartphones, tablets, or laptops as support tools in software evaluation (omitted in the classification for the sake of brevity, because of them being standard). When hardware or both components are considered, scholars use a wider variety of support tools, which includes biofeedback and VR technology and haptics in addition to the ones mentioned above [18, 20, 27, 32].

In terms of participants, when UX and the investigation of usability are the focus of HCI studies, final users are involved to perform evaluations. Experts’ evaluation was employed in addition to final users only in three cases dealing with the software component only.

In terms of typology of product representation, a balance was found as regards the number of contributions using prototypes and end-use products in their experiments. End-use products are slightly more involved (presented in 8 papers) when the software component is considered.

In terms of typology of experience, the ergonomic experience is the most studied one (presented in 10 papers). Cognitive experience follows immediately, while just a few contributions focused on emotional experience, which is generally studied in combination with other kind of experiences. Ergonomic experience is most investigated when software and hardware components are considered separately. In software it is frequently studied alone [22, 25, 27, 30]. Cognitive experience appears more frequently when software and hardware are considered simultaneously [15, 18,19,20, 32].

To summarize, complex systems require broader evaluation and analysis approaches. HCI involving both hardware and software components is difficult to be analyzed in a quantitative way only. To have a complete analysis, it is necessary to combine both qualitative (less objective but more wide-ranging) and quantitative (objective but more limited) approaches. This is reflected in the use of a greater variety of technologies and supporting tools for data acquisition and processing. Unlike the ergonomic and cognitive experiences, emotional ones seem to be largely overlooked in HCI research; The importance of emotions in HCI is stressed also by Cristescu [33], who notice a deficiency in emotional approaches and a prominence of traditional cognitive ones. This this aspect might be seen as a limitation considering transferring HCI approaches to consumer goods and engineering products.

5 Conclusions

This work is intended to get a first understanding of UX and usability in the HCI design field as a trigger to develop UX practices for tangibles. The results achieved are not conducive to conclusive considerations, due to the exploratory nature of this study. A method and criteria for categorizing those kinds of studies represent therefore the necessary first step towards this goal. Based on the proposed approach, the authors examined a sample of convenience of articles proposing case studies where UX is analyzed in combination to the studied software and/or hardware components. To confirm or disconfirm the first insights into HCI, a further analysis of a larger sample of papers is needed. Despite the above limitations, this study was able to capture when software and hardware components are investigated separately or as a whole system, as evident in Sect. 4.