Abstract Voice-based interaction is experiencing a second wind through the advent of machine learning (ML) techniques, affordable consumer products and renewed work on natural language processing (NLP) and large language models (LLMs). A growing body of work is exploring how users perceive new forms of computer-generated voices from qualitative and quantitative angles. However, critical voices have called for greater rigour, especially in confirming the voice as a manipulated variable, i.e. manipulation checks. We present three case studies that highlight the value of investing in rigorous manipulation checks for HCI researchers and designers. We demonstrate the importance of testing assumptions, the need for care and reflection in the design of response options and measurement and the advantages of more exploratory approaches to understanding user perceptions of and user experiences (UX) with voice phenomena. Through these case studies, we raise awareness, empirically justify and critically assess the value of manipulation checks for voice UX research and beyond.

Voice interaction has entered daily life. Yet, the measurement of voice user experience (voice UX) remains underdeveloped. We took a consensus-based approach to the creation of a new instrument grounded in the work of voice UX researchers. For this, we conducted a systemic review of the literature from ACM, IEEE, and Web of Science ( ) to gather a corpus of instruments, measures, and methodological perspectives. We then carried out two validation studies on a range of computer voices, showing through exploratory ( ) and confirmatory factor analyses ( ) that five underlying factors unify the consensus-derived measures. We offer the 24-item Voice Experience Inventory (VOXI) alongside three comprehensive frameworks on key independent and dependent variables and their relationships, anchored to the material that guided our instrument development process. This work represents a timely and community-centred path towards rigorous and standardized measurement of voice UX.

Meditation can enhance mental well-being, but practicing meditation regularly can be challenging. In this work, we present SoulGarden - a gamified, web-based meditation app that draws on the narrative of personal growth, a guiding avatar and several progress-related mechanics to increase users' enjoyment in meditation and thereby enhance their meditation habits, mindfulness, and mental well-being. We conducted a within-subjects field study spanning four weeks (N=30) in which we evaluated the effectiveness of SoulGarden by comparing it to a non-gamified version and baseline measures. Our results show users meditated a lot using SoulGarden and the addition of gamification increased user enjoyment, frequency of meditation, and mindfulness. Thus, we contribute evidence for the potential of gamification to increase engagement and enhance mindfulness in meditation practices, ultimately paving the way to more effective mental health interventions.

Gamification has become one of the main areas in information systems and human–computer interaction research related to users’ motivations and behaviors. Within this context, a significant research gap is the lack of understanding of how users’ characteristics, especially in terms of their preferences for gameful interaction (i.e., user typologies), moderate the effects of gamification and, furthermore, how gamification could be tailored to individual needs. Despite their prominence in classifying users, current typologies and their use in research and practice have received severe criticism regarding validity and reliability, as well as the application and interpretation of their results. Therefore, it is essential to reconsider the relationships and foundations of common user typologies and establish a sound empirical basis to critically discuss their value and limits for personalized gamification. To address this research gap, this study investigated the psychometric properties of the most popular player types within tailored gamification literature (i.e., Bartle’s player types, Yee’s motivations to play, BrainHex, and HEXAD) through a survey study (n=877) using their respective measurement instruments, followed by a correlation analysis to understand their empirical relations and an exploratory factor analysis to identify the underlying factors. The results confirm that user typologies, despite their different origins, show considerable overlap, some being consistent whereas others contradicted theoretically assumed relationships. Furthermore, we show that these four user typologies overall factor into five underlying and fundamental dimensions of Socialization, Escapism, Achievement, Reward Pursuit, and Independence, which could be considered common concepts that may essentially reflect key determinants of user motivation in gamification. Our findings imply that future research and practice in tailored gamification design should shift the focus from developing and applying ever more nuanced typologies to understanding and measuring the key underlying determinants of user motivation in gameful systems. Moreover, given the considerable interrelationships between these determinants, we also argue that researchers should favor continuous representations of users’ motivations in specific situations instead of a dichotomous operationalization of user types as static manifestations of their preferences.

In gamification users show increased motivation and engagement towards tasks. So far, this effect has mostly been empirically tested based on the visual depiction of game elements, while research on the use and addition of auditory aspects is sparse. In this work we investigate the effect of different modalities of game elements (auditory, visual, audiovisual) on user experience, perception and performance in a gamified image-tagging task. We approached this via an online validation survey to find suitable sound effects (N=50), a main quantitative study (N=109) and a qualitative semi-structured interview (N=9). Our results show that while visual gamification increases performance, auditory and audiovisual gamification had no effect. However, they were shown to have an influence on the user's flow state. Our qualitative follow-up study shed light on underlying reasons and revealed each modality has its own drawbacks and advantages and that combining both visual and auditory aspects was preferred by participants.

Entertainment media, including video games, utilize background music (BGM) to enhance ambiance and gameplay, with a growing trend of players replacing in-game audio with personal music for potentially improved gameplay. Yet, research has not systematically investigated the connection between liked or disliked BGM and player behavior and experience. With our work, we make this step by letting users play the popular and well-researched game Tetris with BGM of their choice, and go one step further by adding music to the game that they specifically dislike, as this direction has been neglected thus far, but could prove interesting to target certain player behavior or experience. In our lab-study (N=31) we found that liked BGM increased engagement with the game and enhanced player experience, while disliked music reduced immersion. These findings suggest that music preferences should be taken into greater account in game design, e.g. by offering more options for BGM customization.

The Hexad scale is a crucial tool for personalized gamification in user experience (UX) design. However, completing a 24-item questionnaire can increase dropout rates and screen fatigue within online surveys. When included in larger surveys, scale brevity makes a difference. To reduce the time required for the assessment process, we developed and validated a 12-item version of the Hexad scale. To create it, we carried out an exploratory factor analysis on an existing data set to identify appropriate items (n = 882). To validate the 12-item version, we conducted a confirmatory factor analysis on a new data set (n = 1, 101). Our results show that Hexad-12 outperforms the original Hexad scale regarding model fit, reliability, convergent, and discriminant validity. Therefore, Hexad-12 resolves issues found in studies using the original Hexad scale and provides a suitable and swift instrument for concisely assessing Hexad user types in tailored gamification design.

We lack a shared and detailed understanding in gamification of what game elements are. To address this, we provide a scoping review of the last five years of gamification research, focusing primarily on how game elements have been applied and characterized. We retrieved the definitions of game elements from 280 research papers, conducted a content analysis, and identified their features. On the basis of this information, we provide responses regarding the frequently cited game elements, whether they are consistently characterized in the literature, and the frequently stated features of these elements. Our research has identified 15 game elements in the literature, with points, badges, and leaderboards being the most prevalent. As a first step toward clear definitions, we suggest a set of properties to characterize these game elements. The results of our review contribute to the formation of a consensus among gamification scholars about the application and definition of game elements.

Sound effects (SFX) complement the visual feedback provided by gamification elements in gamified systems. However, the impact of SFX has not been systematically studied. To bridge this gap, we investigate the effects of SFX—supplementing points (as a gamification element)—on task performance and user experience in a gamified image classification task. We created 18 SFX, studied their impact on perceived valence and arousal (N = 49) and selected four suitable SFX to be used in a between-participants user study (N = 317). Our findings show that neither task performance, affect, immersion, nor enjoyment were significantly affected by the sounds. Only the pressure/tension factor differed significantly, indicating that low valence sounds should be avoided to accompany point rewards. Overall, our results suggest that SFX seem to have less impact than expected in gamified systems. Hence, using SFX in gamification should be a more informed choice and should receive more attention in gamification research.

Researchers reference realism in digital games without sufficient specificity. Without clarity about the dimensions of realism, we cannot assess how and when to aim for a higher degree of realism, when lower realism suffices, or when purposeful unrealism is ideal for a game and can benefit player experience (PX). To address this conceptual gap, we conducted a systematic review using thematic synthesis to distinguish between types of realism currently found in the digital games literature. We contribute qualitative themes that showcase contradictory design goals of realism/unrealism. From these themes, we created a framework (i.e., a hierarchical taxonomy and mapping) of realism dimensions in digital games as a conceptual foundation. Our themes and framework enable a workable specificity for designing or analyzing types of realism, equip future work to explore effects of specific realism types on PX, and offer a starting point for similar efforts in non-game applications.

The perception of gamification elements differs across users, which is why personalizing gamified systems is important. Past research showed that the Hexad user types model is particularly suitable for this purpose by demonstrating correlations between user types and gamification elements. However, previous studies were mostly survey-based, i.e. relied on participants' rating of gamification elements based on e.g. textual descriptions or storyboards. Thus, the question whether personalization based on Hexad user types provides benefits in implemented gameful systems was neglected. We contribute to this by investigating the effects of (contra-) tailoring the set of gamification elements to a user's Hexad type on performance and user experience, assessed with survey and physiological measures, in an image tagging context. In a lab study (N=29), we found that gamification increases performance and affects psychophysiological measures of arousal. Moreover, we demonstrate that personalization increases enjoyment, positively-valenced affective experiences and participants' absorption in the task at hand.

In the context of game live-streams, we focus on whether audience influence options can be extended beyond the game, e.g., to the streamers' environment (e.g., controlling their room lighting), the streamers themselves (e.g., activating vibration feedback on their forearms) and the streamers' hardware and peripheral devices (e.g., switching key bindings). An online study (n=81) showed that viewers have mixed feelings and that the context matters, as only a few game genres are assessed as suitable for such an experience. In a lab-study six streamers experienced the idea while playing a horror game. They saw appeal in extending the influence space, but also again highlighted that context matters and customization options are necessary. The studies hint that although this interactivity is from a technical perspective independent of the content streamed, in practice it is not, as the perception is moderated by e.g., the game and why the streamer is playing it.

Abstract Producing and consuming live-streamed content is a growing trend attracting many people today. While the actual content that is streamed is diverse, one especially popular context is games. Streamers of gaming content broadcast how they play digital or analog games, attracting several thousand viewers at once. Previous scientific work has revealed that different motivations drive people to become viewers, which apparently impacts how they interact with the offered features and which streamers’ behaviors they appreciate. In this paper, we wanted to understand whether viewers’ motivations can be formulated as viewer types and systematically measured. We present an exploratory factor analysis (followed by a validation study) with which we developed a 25-item questionnaire assessing five different viewer types. In addition, we analyzed the predictive validity of the viewer types for existing and potential live stream features. We were able to show that a relationship between the assessed viewer type and preferences for streamers’ behaviors and features in a stream exists, which can guide fellow researchers and streamers to understand viewers better and potentially provide more suitable experiences.

Modern, globalized lifestyles make physical separation of family members an inevitable part of life. Due to changes in routines and social roles, remaining connected to distant loved ones is challenging and adversely affects psychological well-being. To support relatedness, we created FamilyFlower, an artificial flower aimed at fostering a connection between remote households by bringing awareness of everyday activities and offering basic expressivity. In its environment, each device detects human presence, movement, sound, and touch. In the remote household, the paired prototype responds by respectively opening the flower bud, actuating the stem, altering the seeds’ color, and dispensing a fragrance. In a 2-week study of deployment between 2 family members, we collected initial impressions of our prototype, and identified key aspects our system could support in future research. From our results, we see that FamilyFlower supports an awareness of ongoing activities in a distant household and built a feeling of connectedness.

Over recent decades, with the fast growth of urbanization, new health-related issues have resulted from the changed lifestyles. People have become more sedentary. They suffer from fully-packed calendars, which does not give them enough time to care for their physical and psychological well-being. While this is a growing challenge, advancements made in internet of things (IoT) devices in the private context offer the chance to develop applications that tackle these issues. While many such applications have been envisioned, the user’s views and requirements for them remain unclear. To better understand this, we conducted a literature review in which we identified the four most common health-related scenarios in which such technologies are used. Next, we conducted an online survey (N=80), in which participants envisioned how smart home devices could realize these scenarios. Based on the results, we derive design implications that show that users value a high degree of customization and the ability to select a specific automation level through an all-in-one, easy-to-use platform.

Abstract Personalizing gameful applications is essential to account for interpersonal differences in the perception of gameful design elements. Considering that an increasing number of people lead sedentary lifestyles, using personalized gameful applications to encourage physical activity is a particularly relevant domain. In this article, we investigate behavior change intentions and Hexad user types as factors to personalize gameful fitness applications. We first explored the potential of these two factors by analyzing differences in the perceived persuasiveness of gameful design elements using a storyboards-based online study ( $$N=178$$ N=178 ). Our results show several significant effects regarding both factors and thus support the usefulness of them in explaining perceptual differences. Based on these findings, we implemented “Endless Universe,” a personalized gameful application encouraging physical activity on a treadmill. We used the system in a laboratory study ( $$N=20$$ N=20 ) to study actual effects of personalization on the users’ performance, enjoyment and affective experiences. While we did not find effects on the immediate performance of users, positive effects on user experience-related measures were found. The results of this study support the relevance of behavior change intentions and Hexad user types for personalizing gameful fitness systems further.

Commonly, gamification is designed by developers and not by end-users. In this paper we investigate an approach where users take control of this process. Firstly, users were asked to describe their own gamification concepts which would motivate them to put more effort into an image tagging task. We selected this task as gamification has already been shown to be effective here in previous work. Based on these descriptions, an implementation was made for each concept and given to the creator. In a between-subjects study (n=71), our approach was compared to a no-gamification condition and two conditions with fixed gamification settings. We found that providing participants with an implementation of their own concept significantly increased the amount of generated tags compared to the other conditions. Although the quality of tags was lower, the number of usable tags remained significantly higher in comparison, suggesting the usefulness of this approach.

While the use of ad blockers prevents negative impacts of advertising on user experience, it poses a serious threat to the business model of commercial web services and freely available content on the web. As an alternative, we investigate the user enjoyment and the advertising effectiveness of playfully deactivating online ads. We created eight game concepts, performed a pre-study assessing the users' perception of them (N=50) and implemented three well-perceived ones. In a lab study (N=72), we found that these game concepts are more enjoyable than deactivating ads without game elements. Additionally, one game concept was even preferred over using an ad blocker. Notably, playfully deactivating ads was shown to have a positive impact on users' brand and product memory, enhancing the advertising effectiveness. Thus, our results indicate that playfully deactivating ads is a promising way of bridging the gap between user enjoyment and effective advertising.

This paper investigates a simple form of customization: giving users the choice to enable or disable gamification. We present a study (N=77) in the context of image tagging, in which a gamification approach was shown to be effective in previous work. In our case, some participants could enable or disable gamification after they had experienced the task with and without it. Other participants had no choice and did the task with or without game elements. The results indicate that those who are not attracted by the elements can be motivated to tag more through this choice. In contrast, those that like the elements are not affected by it. This suggests that systems should provide the option to disable gamification in the absence of more sophisticated tailoring.

Gamification, the use of game elements in non-game contexts, has been successfully used to motivate people to reach their goals more efficiently or turn unpleasant tasks into fun ones. However, most gamified systems are conceptualized for a younger audience and do not account for age-specific changes in the motivation to play or the perception of game elements. To inform the design of gamified applications targeting elderly people (aged 75+), we investigated their gaming experiences, what affects them positively while playing and their attitudes towards the most commonly used game elements. We report findings from semi-structured interviews and a storyboard-based game element assessment (N=18, mean age=84.61), indicating that the main motivation to play is socializing, that participants avoid competition and prefer collaboration and care-taking as well as that badges and points are considered meaningless and provide a level of visibility that puts participants under pressure.

In this paper we investigate "bottom-up" gamification, i.e. providing users with the option to gamify an experience on their own. To this end, we review commonly used gamification elements in terms of their suitability for such an approach and present the results of an online questionnaire (N=75) complemented by semi-structured interviews with employees of a manufacturing company (N=8). In a twelve-day-long study (N=20) we investigated the usefulness of a task managing app implementing a "bottom-up" gamification concept. With these studies, we derived requirements "bottom-up" applications should fulfill. The study results reveal that people want to use such an approach and are open to the creation of their own gamified experience, thus suggesting that "bottom-up" can be an alternative to "top-down" gamification often used today.

We investigate a crowd-based approach to enhance the outcome of optical character recognition in the domain of receipt capturing to keep track of expenses. In contrast to existing work, our approach is capable of extracting single products and provides categorizations for both articles and expenses, through the use of microtasks which are delegated to an unpaid crowd. To evaluate our approach, we developed a smartphone application based on a receipt analysis and an online questionnaire in which users are able to track expenses by taking photos of receipts, and solve microtasks to enhance the recognition. To provide additional motivation to solve these tasks, we make use of gamification. In a three-week-long user study (N=12), we found that our system is appreciated, that our approach reduces the error rate of captured receipts significantly, and that the gamification provided additional motivation to contribute more and thereby enrich the database.

Sorting garbage is a relevant topic in many countries as it contributes to environmental protection. Empirical evidence suggests that not all people separate waste, potentially because they do not know how to do it correctly or are simply not motivated enough. We present the results of an online study (N=184) investigating people's capabilities for classifying waste, their capabilities to improve in this task over time and their current garbage separation behavior. The study confirms that the Wisdom of Crowds is applicable in this context as the crowd produces only half as many errors as the individual and feedback helps participants to improve. Based on this, we introduce the idea of a crowd classifying waste in a game, with their classification result then being used as feedback on gamified public trash cans to educate both the crowd playing the game and people using the trash can playfully.