Opportunities for olfactory interaction in an automotive context

Driving is a highly visual task. Nevertheless, it is a process that involves other senses as well. When we drive, we touch the steering wheel; we listen to what is happening around us, and, even if we are not paying attention to that, we smell what is happening with the car or around it. A scent of gasoline, the burning rubber, the plastic heated up by the sunlight - these are just a few examples. Smell is a very important sense for driving, though it has not been studied much in this context [85], despite being able to provide a much more vivid experience than any other human sense [80]. This thesis aims to fill this gap by investigating opportunities for olfactory interaction in an automotive context. The thesis is mainly focused on designing a scent-delivery device suitable for in-car interaction, on the topic of delivering driving-relevant notifications using scents, and on studying the effects scents have on the driving performance and behaviour, as well as the driver’s mood and well-being. This paper-style PhD thesis consists of two parts. Part II is a collection of seven published papers written in the scope of this thesis, and Part I describes how these papers build a coherent story. Part I starts with an introduction (see Chapter 1) that covers the research questions and contributions of the thesis. It continues with a summary of the background research (see Chapter 2). This overview part then moves on to the description of the approach (see Chapter 3) that covers the process of designing the scent delivery device, the olfactory interaction space, and the studies conducted throughout this PhD. Chapter 4 then summarises the core findings of each study, which are finally discussed in Chapter 5. Part I finishes with a conclusion (see Chapter 6)

OSpace: towards a systematic exploration of olfactory interaction spaces

When designing olfactory interfaces, HCI researchers and practitioners have to carefully consider a number of issues related to the scent delivery, detection, and lingering. These are just a few of the problems to deal with. We present OSpace - an approach for designing, building, and exploring an olfactory interaction space. Our paper is the first to explore in detail not only the scent-delivery parameters but also the air extraction issues. We conducted a user study to demonstrate how the scent detection/lingering times can be acquired under different air extraction conditions, and how the impact of scent type, dilution, and intensity can be investigated. Results show that with our setup, the scents can be perceived by the user within ten seconds and it takes less than nine seconds for the scents to disappear, both when the extraction is on and off. We discuss the practical application of these results for HCI

What did I sniff? Mapping scents onto driving-related messages

The sense of smell is well known to provide very vivid experiences and to mediate a strong activation of crossmodal semantic representations. Despite a growing number of olfactory HCI prototypes, there have been only a few attempts to study the sense of smell as an interaction modality. Here, we focus on the exploration of olfaction for in-car interaction design by establishing a mapping between three different driving-related messages ("Slow down", "Fill gas", "Passing by a point of interest") and four scents (lemon, lavender, peppermint, rose). The results of our first study demonstrate strong associations between, for instance, the "Slow down" message and the scent of lemon, the "Fill gas" message and the scent of peppermint, the "Passing by a point of interest" message and the scent of rose. These findings have been confirmed in our second study, where participants expressed their mapping preferences while performing a simulated driving task

CARoma therapy: pleasant scents promote safer driving, better mood, and improved well-being in angry drivers

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

I smell trouble: using multiple scents to convey driving-relevant information

Cars provide drivers with task-related information (e.g. "Fill gas") mainly using visual and auditory stimuli. However, those stimuli may distract or overwhelm the driver, causing unnecessary stress. Here, we propose olfactory stimulation as a novel feedback modality to support the perception of visual notifications, reducing the visual demand of the driver. Based on previous research, we explore the application of the scents of lavender, peppermint, and lemon to convey three driving-relevant messages (i.e. "Slow down", "Short inter-vehicle distance", "Lane departure"). Our paper is the first to demonstrate the application of olfactory conditioning in the context of driving and to explore how multiple olfactory notifications change the driving behaviour. Our findings demonstrate that olfactory notifications are perceived as less distracting, more comfortable, and more helpful than visual notifications. Drivers also make less driving mistakes when exposed to olfactory notifications. We discuss how these findings inform the design of future in-car user interfaces

A comparison of scent-delivery devices and their meaningful use for in-car olfactory interaction

In the field of Human Computer Interaction (HCI), vision and audition have been the dominating modalities for interacting with users. This is despite the fact that humans are equipped with five basic senses. Because of this, there is a limited number of tools that harness the olfactory system as a communication channel. Recently, several promising scent-delivery devices have been developed, however, there is a lack of guidance on how to use them in a meaningful way for different interactive tasks. In this paper, we propose a three-dimensional framework to compare different scent-delivery devices based on the distance, volume, and speed of the scent-delivery. We discuss how this initial exploration can guide the design of in-car olfactory interfaces beyond previous work on drivers' physical and emotional state

SMELL SPACE:Mapping out the olfactory design space for novel interactions

The human sense of smell is powerful. However, the way we use smell as an interaction modality in human–computer interaction (HCI) is limited. We lack a common reference point to guide designers’ choices when using smell. Here, we map out an olfactory design space to provide designers with such guidance. We identified four key design features: (i) chemical, (ii) emotional, (iii) spatial, and (iv) temporal. Each feature defines a building block for smell-based interaction design and is grounded in a review of the relevant scientific literature. We then demonstrate the design opportunities in three application cases. Each application (i.e., one desktop, two virtual reality implementations) highlights the design choices alongside the implementation and evaluation possibilities in using smell. We conclude by discussing how identifying those design features facilitates a healthy growth of this research domain and contributes to an intermediate-level knowledge space. Finally, we discuss further challenges the HCI community needs to tackle

SmellControl: the study of sense of agency in smell

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