Physical activity trackers rely on fixed daily step goals, treating the day as the primary unit for planning and evaluating activity. However, these goals often misalign with everyday life: schedules fluctuate, opportunities for movement vary, and long-term targets can be difficult to sustain, leading to frustration and disengagement. Despite growing evidence that short bouts of movement can meaningfully improve health, current systems provide limited support for acting on these brief, situated opportunities. This paper investigates micro-goals (i.e., brief, situated goals) as an alternative framing for supporting physical activity. We developed Mikro, a smartwatch app enabling on-the-go micro-goal setting, and deployed it in a 27-day field study with 16 participants. Our findings show that micro-goals encouraged frequent tailoring, supported immediate action, and helped participants capitalize on small opportunities for movement. We argue that micro-goals can complement daily step targets by scaffolding more flexible, adaptive, and engaging ways of staying active.

Fact-checking has emerged as a principal part of news reporting with over 400 fact-checking organisations worldwide. However, fewer than one in ten individuals report having used a fact-checking service. In this paper, we introduce Google Inject: a technology-mediated nudge that integrates, relevant to one's query, fact-checks, into the Google search results page. We report on a laboratory study that inquired into how four design variables, in particular, the number of fact-checking articles injected, their positioning, concealment and seamlessness affect users' experience and proximal behaviours with Google Inject. All in all, the paper highlights the complexity and importance of nudge design, as seemingly subtle variations in the design and implementation of a nudge can have a profound impact on its effectiveness.

It is increasingly acknowledged that simply presenting users with corrective information is unlikely to produce the desired effects against misinformation. As such, the need for systematic use of behavioral theory is increasingly acknowledged, and behavioral interventions against misinformation are rising. This paper presents a scoping review of digital behavioral interventions countering misinformation, inquiring into their behavioral objectives, theoretical foundations, design and evaluation practices, and the factors that were empirically proven, or speculated, to contribute to interventions' failure. Among others, we identify 17 distinct behavioral objectives, organized into three stages of the online news cycle: composition, amplification and consumption, 24 theoretical frameworks employed in designing these interventions, and nine reasons of failure. We synthesize the findings into a set of design cards with the goal of guiding intervention designers during concept ideation and refinement, and highlight areas for future research.

The importance of behaviorally informed interventions against misinformation is increasingly acknowledged, and the concept of nudging has received attention as a promising approach to promoting conscious decision-making when confronted with online misinformation. Nudges, however, may not always produce the desired behaviors; they may lead to side effects, and even backfire. With nudges most often being studied behaviorally, this article argues for the importance of inquiring into users’ perceptions before deploying nudges in the field. We employ a semi-structured interviewing technique, the Repertory-Grid Technique, to inquire into how end-users, like citizens, journalists and policymakers, perceive six concepts of technology-mediated nudging designed to counter online misinformation. The study identifies nine construct categories, such as respectfulness, proactivity, and simplicity, which participants employed to differentiate among and evaluate the nudges. By considering these constructs during nudge design, choice architects can mitigate risks regarding their acceptance and sustained effectiveness. This study contributes to a growing body of literature on the factors that shape nudge failure.

Interest in technological solutions for combating online misinformation has rapidly grown over the last decade, yet the majority of proposed tools do not consider behavioral theories in their design, nor have they addressed the ways in which individuals could potentially interact with these tools, while omitting the plausible ways in which variations in the design of the interventions may affect end-users’ decision-making and behavioral responses. In this paper, we explore the potential of nudging to inform the design of technological tools that aim to mitigate online misinformation through behavior change. We report on a design workshop where 29 participants were asked to conceive technology-mediated nudges supporting individuals’ decision-making in the production, dissemination or consumption of misinformative content. In producing novel solutions, participants used the “Nudge Deck,” a design support tool that makes nudge theory, and particularly a framework of 23 interaction design mechanisms for nudging, accessible during time-constrained design meetings. We present the outputs of the session and discuss them in light of prior literature with respect to ethics and potential effectiveness.

Despite a wealth of behavior change theories and techniques available, designers often struggle to apply theory in the design of behavior change technologies. We present the Behavior Change Design (BCD) cards, a design support tool that makes behavioral science theory accessible to interaction designers during design meetings. Grounded on two theoretical frameworks of behavior change, the BCD cards attempt to map 34 behavior change techniques to five stages of behavior change, thus assisting designers in selecting appropriate techniques for given behavioral objectives. We present the design of the BCD cards along with the results of two formative and one summative study that aimed at informing the design of the cards and assessing their impact on the design process.

The idea of nudging - that subtle changes in the 'choice architecture' can alter people's behaviors in predictable ways - was eagerly adopted by HCI researchers and practitioners over the past decade. Yet, the design of effective nudging interventions is far from trivial, with theoretical knowledge being unstructured, with over a hundred cognitive biases found online, and inaccessible to practitioners during design meetings. We present the design and evaluation of the Nudge Deck, a card-based, design support tool that provides actionable knowledge for the design of technology-mediated nudges. The tool was evaluated through two case studies where 58 participants were asked to design nudging interventions, in the contexts of physical activity promotion and misinformation mitigation, with and without the cards. We report on how the cards enhanced designers' self-efficacy, and led to more theoretically grounded, creative and appropriate for the context, ideas.

Despite the recent increase in interest in the experience sampling method (ESM), researchers have repeatedly criticised the high burden and levels of interruption that it imposes on participants, and alternative cost-effective methods, such as the Day Reconstruction Method (DRM), have been adopted by the Human-Computer Interaction (HCI) community. In this paper, we review the use of ESM and DRM in the HCI field and argue for a new paradigm called Technology-Assisted Reconstruction (TAR), according to which passively logged data of users’ behaviours are used in assisting the later reconstruction of experiences and behaviours. We discuss five methods of Technology-Assisted Reconstruction that we have developed in our past work and conclude with a framework that highlights three directions for Technology-Assisted Reconstruction.

Ten years ago, Thaler and Sunstein introduced the notion of nudging to talk about how subtle changes in the 'choice architecture' can alter people's behaviors in predictable ways. This idea was eagerly adopted in HCI and applied in multiple contexts, including health, sustainability and privacy. Despite this, we still lack an understanding of how to design effective technology-mediated nudges. In this paper we present a systematic review of the use of nudging in HCI research with the goal of laying out the design space of technology-mediated nudging - the why (i.e., which cognitive biases do nudges combat) and the how (i.e., what exact mechanisms do nudges employ to incur behavior change). All in all, we found 23 distinct mechanisms of nudging, grouped in 6 categories, and leveraging 15 different cognitive biases. We present these as a framework for technology-mediated nudging, and discuss the factors shaping nudges' effectiveness and their ethical implications.

While recent research has emphasized the importance of understanding the lived experience of personal tracking, very little is known about the everyday coordination between tracker use and the surrounding environment. We combine behavioral data from trackers with video recordings from wearable cameras, in an attempt to understand how usage unfolds in daily life and how it is shaped by the context of use. We recorded twelve participants' daily use of activity trackers, collecting and analyzing 244 incidents where activity trackers were used. Among our findings, tracker use was strongly driven by reflection and learning-in action, contrasting the traditional view that learning is one of deep exploration, following the collection of data on behaviors. We leverage on these insights and propose three directions for the design of activity trackers: facilitating learning through glances, providing normative feedback and facilitating micro-plans.

The active monitoring of workload levels has been found to significantly reduce work-related stress. Heart rate and heart rate variability (HRV) measurements via photoplethysmography (PPG) sensors have shown a strong potential to accurately describe daily workload levels. However, due its complexity, HRV is commonly misunderstood and the associated measurements are rarely incorporated for workload monitoring in novel technological devices such as smartwatches and activity trackers. In this paper we explore the potential of consumer-grade smartwatches, equipped with PPG sensors, to assist in the active monitoring of workload during work hours. We develop a prototype that employs the SDNN index, a powerful HRV marker for cardiac resilience to differentiate between high and low workload levels along the work day, and presents feedback in glanceable form, by highlighting workload levels and physical activity over the past hour in 5-minutes blocks at the periphery of the smartwatch. A field study with 9 participants and 3 variations of our prototype attempts to quantify the impact of the HRV feedback over subjective and objective workload as well as users' engagement with the smartwatch. Results showed workload levels as inferred from the PPG sensor to positively correlate with self-reported workload and HRV feedback to result to lower levels of workload as compared to a conventional activity tracker. Moreover, users engaged more frequently with the smartwatch when HRV feedback was presented, than when only physical activity feedback was provided. The results suggest that HRV as inferred from PPG sensors in wearables can effectively be used to monitor workload levels during work hours.

Recent research reveals over 70% of the usage of physical activity trackers to be driven by glances -- brief, 5-second sessions where individuals check ongoing activity levels with no further interaction. This raises a question as to how to best design glanceable behavioral feedback. We first set out to explore the design space of glanceable feedback in physical activity trackers, which resulted in 21 unique concepts and 6 design qualities: being abstract, integrating with existing activities, supporting comparisons to targets and norms, being actionable, having the capacity to lead to checking habits and to act as a proxy to further engagement. Second, we prototyped four of the concepts and deployed them in the wild to better understand how different types of glanceable behavioral feedback affect user engagement and physical activity. We found significant differences among the prototypes, all in all, highlighting the surprisingly strong effect glanceable feedback has on individuals' behaviors.

This paper presents insights on driver's User Experience (UX) in terms of systematically investigating predicted experience, actual experience, and recalled experience. By conducting a three-week field study with car commuters in two countries, we studied how frustration and anger differentiate in prediction, actual experience, and recall. Our results show that commuters accurately predict their upcoming anger or frustration in a traffic congestion, however, lower their experienced frustration when being recalled. Moreover, unexpected traffic congestions (in contrast to expected ones) are prone to higher levels of anger. We further found that time of day is related to the prediction of anger, and mood is related to the prediction of frustration. With our study we provide a holistic view on commuters' everyday emotions and experiences -- not only when being on the road, but also before and after the trip.

We report on a 10-month in-the-wild study of the adoption, engagement and discontinuation of an activity tracker called Habito, by a sample of 256 users who installed the tracker on their own volition. We found 'readiness' to behavior change to be a strong predictor of adoption (which ranged from 56% to 20%). Among adopters, only a third updated their daily goal, which in turn impacted their physical activity levels. The use of the tracker was dominated by glances -- brief, 5-sec sessions where users called the app to check their current activity levels with no further interaction, while users displayed true lack of interest in historical data. Textual feedback proved highly effective in fueling further engagement with the tracker as well as inducing physical activity. We propose three directions for design: designing for different levels of 'readiness', designing for multilayered and playful goal setting, and designing for sustained engagement.

Gamification, the use of game design elements, such as points, levels, badges and achievements, in non-game contexts is a promising approach for encouraging desired behaviors. In this paper we describe our design process and early evaluation of a prototype that sensed children's social interactions (i.e., physical proximity) in the playground, and attempted to encourage pro-social behaviors through motivational feedback on a public display. We illustrate how we came to realize the potentially detrimental effect of gamification on children's intrinsic motivation and depth of reflection, and how we attempted to circumvent this through encouraging empathic understanding on children regarding the consequences of their behaviors on others.

With an increasing emphasis on behavior change technologies, interest has grown over time also on the role of HCI in motivating healthy tooth brushing habits on children. In this paper we present the design and development of SmartHolder, a toothbrush holder that senses the frequency and duration of toothbrush practices and motivates healthy tooth brushing habits, through raising family members' awareness of each other's practices. Wed first present two preliminary studies about children's and adults' tooth brushing behaviors and how these are influenced by social interactions within the family. We conclude through a presentation of early conceptual designs as well as an initial working prototype of SmartHolder.

Although advances in technology now enable people to communicate ‘anytime, anyplace’, it is not clear how citizens can be motivated to actually do so. This paper evaluates the impact of three principles of psychological empowerment, namely perceived self-efficacy, sense of community and causal importance, on public transport passengers’ motivation to report issues and complaints while on the move. A week-long study with 65 participants revealed that self-efficacy and causal importance increased participation in short bursts and increased perceptions of service quality over longer periods. Finally, we discuss the implications of these findings for citizen participation projects and reflect on design opportunities for mobile technologies that motivate citizen participation.

Safeguarding personally identifiable information (PII) is crucial because such information is increasingly used to engineer privacy attacks, identity thefts and security breaches. But is it likely that individuals may choose to just share this information with strangers? This study examines how reciprocation can lead to the disclosure of PII between strangers in online social networking. We demonstrate that the widespread use of public, one-to-many, communication channels such as ‘wall posts’ and profile pages in online social networks poses an exception to the assumption that reciprocation happens on one-to-one channels. We find that individuals not only reciprocate and share PII when the disclosure of such information is private and directed towards them by a stranger, but also when the stranger shares this information through a public channel that is not directed towards anyone in particular. Implications for privacy and design are discussed.

In this study, we demonstrate how analysis of users’ social network structure—a topic that has remained until recently inconspicuous within Human-Computer Interaction (HCI) research on social systems—can contribute to our understanding of Social Networking Services (SNS) effect on users. Despite a consensus that SNS enhance people's social capital, prior studies on SNS have provided inconsistent evidence on this process. In a multipronged study, we analyze personality, social capital, and Facebook data from a cohort of participants to model the extent to which one's SNS reflects aspects of his or personality and affects his bridging social capital. Our empirically validated model shows that empathy and conscientiousness influence the structural holes in one's social network, which in turn affects bridging social capital. These findings highlight the importance of network structure as an intermediary between one's personality and the social benefits one reaps from using SNS. Our work demonstrates how the implicit structural information embedded in users’ social networks can provide key insights into users’ personality and social capital.

Measuring children's behaviors and experiences has been one of the core interests of the field of Child-Computer Interaction. However, maintaining children's engagement in the evaluation process is one of the challenges that researchers need to meet. In this paper we introduce Playful Booth, a system that aimed at engaging children in playful photo taking practices with the goal of capturing their social interactions over prolonged periods of time. We then present a 4-week-long deployment of Playful Booth with a total of seventy children that aimed at addressing three research questions. First, does playful booth create initial engagement on children and does it sustain this engagement over prolonged periods of time? Second, can the deployment be sustained for prolonged periods of time with minimal resources? Last, do behavioral data as captured from playful booth reflect children's actual social participation in the school community?

Awareness campaigns aiming to highlight the accessibility challenges affecting people with disabilities face an important challenge. They often describe the environmental features that pose accessibility barriers out of context, and as a result public cannot relate to the problems at hand. In this paper we demonstrate that contextual cues can enhance people's perception and understanding of accessibility. We describe a two-week study where our participants submitted reports of inaccessible spots all over the city through a web application. Using a 2x2 factorial design we contrast the impact of two types of contextual cues, visual cues (i.e., displaying a picture of the inaccessible spot) and location cues (i.e., ability to zoom-in the exact location). We measure participants' perceptions of accessibility and how they are challenged to consider their own limitations and barriers that may also affect themselves in certain circumstances. Our results suggest that visual cues led to a bigger sense of urgency while also improving participants' attitude towards disability.

In this paper we adopt a network science approach to investigate empathy and its implications for online social networks. We demonstrate that empathy is closely linked to social capital - the findings suggest that individuals higher on cognitive empathic skill are overall likely to report both higher bridging and higher bonding social capital. On the other hand, attributes of network structure around the individual, quantified through networks analysis metrics, were related to cognitive empathy. Further, an examination of the interplay between network structure, social capital and empathy suggests that empathy facilitates the relation between network structure and social capital previously reported in literature. We discuss the implications of our findings for the understanding of empathy in the context of online social networks and for the design of these systems.

As HCI shifts "to the wild", in-situ methods such as Diary Methods and the Experience Sampling Method are gaining momentum. However, researchers have acknowledged the intrusiveness and lack of realism in these methods and have proposed solutions, notably through lightweight and rich media capture. In this paper we explore the concept of lifelogging as an alternative solution to these two challenges. We describe Footprint Tracker, a tool that allows the review of lifelogs with the aim to support recall and reflection over daily activities and experiences. In a field trial, we study how four different types of cues, namely visual, location, temporal and social context, trigger memories of recent events and associated emotions. We conclude with a number of implications for the design of lifelogging systems that support recall and reflection upon recent events as well as ones lying further in our past.

With the increasing sophistication of mobile computing, a growing interest has been paid to locative media that aim at providing immersive experiences. Location aware narratives are a particular kind of locative media that aim at “telling stories that unfold in real space”. This paper presents a study that aimed at assessing an underlying hypothesis of location-aware narratives: that the coupling between the physical space and the narrative will result in increased levels of immersion in the narrative. Forty-five individuals experienced a location-aware video narrative in three locations: (a) the original location that contains physical cues from the narrative world, (b) a different location that yet portrays a similar atmosphere, and (c) a location that contains neither physical cues nor a similar atmosphere. Significant differences were found in users’ experiences with the narrative in terms of immersion in the story and mental imagery, but not with regard to feelings of presence, emotional involvement or the memorability of story elements. We reflect on these findings and the implications for the design of location-aware narratives and highlight questions for further research.

The goal of user experience design in industry is to improve customer satisfaction and loyalty through the utility, ease of use, and pleasure provided in the interaction with a product. So far, user experience studies have mostly focused on short-term evaluations and consequently on aspects relating to the initial adoption of new product designs. Nevertheless, the relationship between the user and the product evolves over long periods of time and the relevance of prolonged use for market success has been recently highlighted. In this paper, we argue for the cost-effective elicitation of longitudinal user experience data. We propose a method called the “UX Curve” which aims at assisting users in retrospectively reporting how and why their experience with a product has changed over time. The usefulness of the UX Curve method was assessed in a qualitative study with 20 mobile phone users. In particular, we investigated how users’ specific memories of their experiences with their mobile phones guide their behavior and their willingness to recommend the product to others. The results suggest that the UX Curve method enables users and researchers to determine the quality of long-term user experience and the influences that improve user experience over time or cause it to deteriorate. The method provided rich qualitative data and we found that an improving trend of perceived attractiveness of mobile phones was related to user satisfaction and willingness to recommend their phone to friends. This highlights that sustaining perceived attractiveness can be a differentiating factor in the user acceptance of personal interactive products such as mobile phones. The study suggests that the proposed method can be used as a straightforward tool for understanding the reasons why user experience improves or worsens in long-term product use and how these reasons relate to customer loyalty.

A wealth of studies in the field of user experience have tried to conceptualize new measures of product quality and inquire into how the overall goodness of a product is formed on the basis of product quality perceptions. An interesting question relates to how the perception as well as the relative dominance of different product qualities evolve across different phases in the adoption of a product. However, temporality of experience poses substantial challenges to traditional reductive evaluation approaches. In this paper we present an alternative methodological approach for studying how users’ experiences with interactive products develop over time. The approach lies in the elicitation of rich qualitative insights in the form of experience narratives, combined with content-analytical approaches for the aggregation of idiosyncratic insights into generalized knowledge. We describe a tool designed for eliciting rich experience narratives retrospectively, and illustrate this tool by means of a study that inquired into how users’ experiences with mobile phones change over the first 6 months of use. We use the insights of the study to validate and extend a framework of temporality proposed by Karapanos et al. (2009b).

In this paper we argue against averaging as a common practice in the analysis of subjective attribute judgments, both across and within subjects. Previous work has raised awareness of the diversity between individuals' perceptions. In this paper it will furthermore become apparent that such diversity can also exist within a single individual, in the sense that different attribute judgments from a subject may reveal different, complementary, views. A Multi-Dimensional Scaling approach that accounts for the diverse views on a set of stimuli is proposed and its added value is illustrated using published data. We will illustrate that the averaging analysis provides insight to only 1/6th of the total number of attributes in the example dataset. The proposed approach accounts for more than double the information obtained from the average model, and provides richer and semantically diverse views on the set of stimuli.

A recent trend in Human-Computer Interaction (HCI) research addresses human needs that go beyond the instrumental, resulting in an increasing body of knowledge about how users form overall evaluative judgments on the quality of interactive products. An aspect largely neglected so far is that of temporality, i.e. how the quality of users' experience develops over time. This paper presents an in-depth, five-week ethnographic study that followed 6 individuals during an actual purchase of the Apple iPhone". We found prolonged use to be motivated by different qualities than the ones that provided positive initial experiences. Overall, while early experiences seemed to relate mostly to hedonic aspects of product use, prolonged experiences became increasingly more tied to aspects reflecting how the product becomes meaningful in one's life. Based on the findings, we promote three directions for CHI practice: designing for meaningful mediation, designing for daily rituals, and designing for the self.

In this paper we describe a study that explored the implications of the Social Translucence framework for designing systems that support communications at work. Two systems designed for communicating availability status were empirically evaluated to understand what constitutes a successful way to achieve Visibility of people's communicative state. Some aspects of the Social Translucence constructs: Visibility, Awareness and Accountability were further operationalized into a questionnaire and tested relationships between these constructs through path modeling techniques. We found that to improve Visibility systems should support people in presenting their status in a contextualized yet abstract manner. Visibility was also found to have an impact on Awareness and Accountability but no significant relationship was seen between Awareness and Accountability. We argue that to design socially translucent systems it is insufficient to visualize people's availability status. It is also necessary to introduce mechanisms stimulating mutual Awareness that allow for maintaining shared, reciprocical knowledge about communicators' availability state, which then can encourage them to act in a socially responsible way.