Biosensing technologies are increasingly available as offthe-shelf products, yet for many designers, artists and nonengineers, these technologies remain difficult to design with. Through a soma design stance, we devised a novel approach for exploring qualities in biodata. Our explorative process culminated in the design of three artefacts, coupling biosignals to tangible actuation formats. By making biodata perceivable as sound, in tangible form or directly on the skin, it became possible to link qualities of the measurements to our own somatics-our felt experience of our bodily bioprocessesas they dynamically unfold, spurring somatically-grounded design discoveries of novel possible interactions. We show that making biodata attainable for a felt experience-or as we frame it: turning biodata into somadata-enables not only first-person encounters, but also supports collaborative design processes as the somadata can be shared and experienced dynamically, right at the moment when we explore design ideas.

In the last decade, the number of articles on HCI and health has increased dramatically. We extracted 139 papers on depression, anxiety and bipolar health issues from 10 years of SIGCHI conference proceedings. 72 of these were published in the last two years. A systematic analysis of this growing body of literature revealed that most innovation happens in automated diagnosis, and self-tracking, although there are innovative ideas in tangible interfaces. We noted an overemphasis on data production without consideration of how it leads to fruitful interventions. Moreover, we see a need to promote ethical practices for involvement of people living with affective disorders. Finally, although only 16 studies evaluate technologies in a clinical context, several forms of support and intervention illustrate how rich insights are gained from evaluations with real patients. Our findings highlight potential for growth in the design space of affective health technologies.

Emotions are vital to our lives but could be difficult to recognize and understand. Traditional visualizations of emotions tend to be time-series graph on screen displays limiting user engagement in their real-time sense-making. This paper explores the feasibility of smart materials for developing novel dynamic displays on skin for real time visualization of affective data. We report prototyping two such displays and their evaluation with 6 participants, and discuss their qualities such as ambiguity, slowly unfolding change, and lack of light emission together with their temporal constraints and private-public tension for affective meaning disclosure.

Stress is one of the most significant health problems in today's world. Existing work has used heart rate variability (HRV) to detect stress and provide biofeedback in order to regulate it. There has been a growing interest in using wearable biosensors to measure HRV. Each of these sensors acquires heart rate data using different technologies for various bodily locations, therefore posing a challenge for researchers to decide upon a particular device in a research experiment. Previous work has only compared different sensing devices against a gold standard in terms of data quality, thus overlooking qualitative analysis for the usability and acceptability of such devices. This paper introduces a mixed-methods approach to compare the data quality and user acceptance of the six most common wearable heart rate monitoring biosensors. We conducted a 70-minute data collection procedure to obtain HRV data from 32 participants followed by a 10-minute semi-structured interview on sensors' wearability and comfort, long-term use, aesthetics, and social acceptance. We performed quantitative analysis consisting of correlation and agreement analysis on the HRV data and thematic analysis on qualitative data obtained from interviews. Our results show that the electrocardiography (ECG) chest strap achieved the highest correlation and agreement levels in all sessions and had the lowest amount of artifacts, followed by the photoplethysmography (PPG) wristband, ECG sensor board kit and PPG smartwatch. In all three sessions, wrist-worn devices showed a lower amount of agreement and correlation with the reference device. Qualitative findings from interviews highlight that participants prefer wrist and arm-worn devices in terms of aesthetics, wearability, and comfort, followed by chest-worn devices. Moreover, participants mentioned that the latter are more likely to invite social judgment from others, and they would not want to wear it in public. Participants preferred the chest strap for short-term use and the wrist and arm-worn sensors over long-time.

Increasing HCI work on affective interfaces aimed to capture and communicate users' emotions in order to support self-understanding. While most such interfaces employ traditional screen-based displays, more novel approaches have started to investigate smart materials and actuators-based prototypes. In this paper, we describe our exploration of smart materials and actuators leveraging their temporal qualities as well as common metaphors for real-time representation of changes in arousal through visual and haptic modalities. This exploration provided rationale for the design and implementation of six novel wrist-worn prototypes evaluated with 12 users who wore them over 2 days. Our findings describe how people use them in daily life, and how their material-driven qualities such as responsiveness, duration, rhythm, inertia, aliveness and range shape people's emotion identification, attribution, and regulation. Our findings led to four design implications including support for affective chronometry for both raise and decay time of emotional response, design for slowness, and for expressiveness.