Figure 1: The research involved: (i) a design futuring workshop on acoustophoresis, (ii) the development and feasibility assessment of two SONARIOS (i.e., scenarios), and (iii) the synthesis of three strong concepts, along with key tensions and responsibilities in shaping the future of acoustophoresis applications.

Recovering a lost ability is rarely easy, but unlike strengthening a muscle, progress in smell training, repeated exposure to specific scents to support recovery or maintain function, is often invisible. For those undergoing Digital Smell Training (DST), data visualisations may be the only markers of change. But how can graphs and numbers sustain motivation over months of slow, unpredictable recovery? This pictorial adopts a Research through Design approach to explore how data visualisations might better support motivation, adherence, and long-term engagement in DST. We draw on a six-month in-home study with 18 participants with varying olfactory abilities using a technology probe. Following initial feedback, we ran a co-design workshop to understand participants’ visualisation needs. These insights informed eight design directions and three visualisation concepts, later evaluated in a focus group. We explore how visualisations help ‘flip perspectives’, from tracking outcomes to nurturing perseverance across the uncertain journey of smell rehabilitation.

Take a deep breath; what do you smell? While sight and hearing dominate our perceptions, the sense of smell is often overlooked, even undervalued. However, the importance of our sense of smell goes beyond detecting odours. It shapes our emotions, memories, behaviour, and quality of life. Recent advances in olfactory interfaces have sparked discussions about the future of smell in human-computer interaction. While efforts mainly focus on the realization of new olfactory interfaces, here we collectively explore alternative worlds centred around the sense of smell. First, we conducted a design futuring workshop involving individuals with varying smell capabilities and expertise to envision and discuss smell-centred futures. Then, through iterative reflection, we arrived at three smell worlds presented as narratives and visuals. From this conceptual work, we offer new perspectives and generative possibilities for design research that prioritizes our noses.

Human perception of touch is a complex interplay of sensory inputs, extending beyond tactile stimuli to include visual and auditory cues. Yet, the potential of olfactory cues (e.g., scents) to enrich our understanding and experiences of digital touch remains largely unexplored. This paper explores the integration of scent with digital haptic feedback, specifically focusing on the perception of textiles using an ultrasonic mid-air haptic device. In an initial validation study, we identified scents associated with the tactile properties of roughness, smoothness, coldness, and warmth based on participant ratings (n = 31). In a subsequent immersive Virtual Reality (VR) experiment, we explored how these scents might affect perceptions of digital textiles presented using ultrasonic mid-air haptics (n = 32). Our results suggested that while scents did not affect the tactile properties of digital textiles, participants reported the sensations feeling more realistic and more arousing according to the scent delivered. This multimodal integration of scent with digital haptic stimuli can open up the creation of more immersive experiences and more in-depth understanding of digital material properties.

Previous research has shown the influence of smell on emotions, memories, and body image. However, most of this work has taken place in laboratory settings and little is known about the influence of smell in real-world environments. In this article, we present novel insights gained from a field study investigating the emotional effect of smell on memories and body image. Taking inspiration from the cultural design probes approach, we designed QuintEssence, a probe package that includes three scents and materials to complete three tasks over a period of four weeks. Here, we describe the design of QuintEssence and the main findings based on the outcomes of the three tasks and a final individual interview. The findings show similar results between participants based on the scent. For example, with cinnamon, participants experienced feelings of warmth, coziness, happiness, and relaxation; they recalled blurred memories of past moments about themselves and reported a general feeling of being calm and peaceful towards their bodies. Our findings open up new design spaces for multisensory experiences and inspire future qualitative explorations beyond laboratory boundaries.

Driving is a task that is often affected by emotions. The effect of emotions on driving has been extensively studied. Anger is an emotion that dominates in such investigations. Despite the knowledge on strong links between scents and emotions, few studies have explored the effect of olfactory stimulation in a context of driving. Such an outcome provides HCI practitioners very little knowledge on how to design for emotions using olfactory stimulation in the car. We carried out three studies to select scents of different valence and arousal levels (i.e. rose, peppermint, and civet) and anger eliciting stimuli (i.e. affective pictures and on-road events). We used this knowledge to conduct the fourth user study investigating how the selected scents change the emotional state, well-being, and driving behaviour of drivers in an induced angry state. Our findings enable better decisions on what scents to choose when designing interactions for angry drivers.

The Sense of Agency (SoA) is crucial in interaction with technology, it refers to the feeling of 'I did that' as opposed to 'the system did that' supporting a feeling of being in control. Research in human-computer interaction has recently studied agency in visual, auditory and haptic interfaces, however the role of smell on agency remains unknown. Our sense of smell is quite powerful to elicit emotions, memories and awareness of the environment, which has been exploited to enhance user experiences (e.g., in VR and driving scenarios). In light of increased interest in designing multimodal interfaces including smell and its close link with emotions, we investigated, for the first time, the effect of smell-induced emotions on the SoA. We conducted a study using the Intentional Binding (IB) paradigm used to measure SoA while participants were exposed to three scents with different valence (pleasant, unpleasant, neutral). Our results show that participants? SoA increased with a pleasant scent compared to neutral and unpleasant scents. We discuss how our results can inform the design of multimodal and future olfactory interfaces.