CARoma Therapy: Pleasant Scents Promote Safer Driving, Better Mood, and Improved Well-Being in Angry Drivers

Abstract

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.

When Do Drivers Interact with In-Vehicle Well-being Interventions?

“…Intuitively, smartphonebased interventions might not be suitable for use while driving. Given the amount of time an average person spends driving, however, recent research has adapted interventions to be delivered in the context of the car, e.g., audio-based interventions [8], odor-based interventions [17], or ambient-light-based interventions [24]. While in-vehicle interventions provide a unique opportunity to improve a person's well-being, it is important to deliver these interventions at times unlikely to distract the driver from their primary task of driving.…”

“…In other work, Dmitrijs et al explored the effectiveness of subtle, odor-based well-being interventions in the car [17]. In four laboratory studies, Dmitrijs et al identified different scents for emotion regulation, tested them on drivers in a simulator and found out that pleasant scents can relax drivers, ergo making them safer drivers [17].…”

“…In other work, Dmitrijs et al explored the effectiveness of subtle, odor-based well-being interventions in the car [17]. In four laboratory studies, Dmitrijs et al identified different scents for emotion regulation, tested them on drivers in a simulator and found out that pleasant scents can relax drivers, ergo making them safer drivers [17]. Braun et al conducted a controlled, real-world driving study in which they personalized voice assistants to the driver's personality and driving situation, and found that extroverted people preferred a friendly tone in the assistant's voice ś which led to more trust and was perceived as pleasant [8].…”

“…Furthermore, we only evaluated interaction with two specific types of audio-based interventions with varying cognitive loads. Interaction with other forms of interventions, such as haptic-or odor-based interventions [4,17] could be different from audio-based interventions and is something we hope to explore in future work. Finally, in terms of analyses, we only considered CAN data.…”

“…Balters et al further evaluated the slow-breathing intervention in a controlled, real-world driving condition on a test track, and found that the intervention led to a reduction in breathing rate and physiological arousal for drivers who engaged with the intervention [4]. Dimitijs et al designed an odor-based intervention to improve well-being while driving [17]. In related work, Braun et al conducted a controlled, real-world study to evaluate the effectiveness of a personalized voice assistant on positive emotions experienced by a driver [8].…”