Human-computer interaction (HCI) has traditionally focused on designing and investigating interfaces that provide explicit visual, auditory, or haptic feedback. We propose a new type of user interface that uses smell as an implicit, less conscious output that still influences the person's cognition. We pair that with implicit, physiological information as the input to the system.
Unlike other modalities, certain types of olfactory stimuli can be presented during sleep, without awakening the subject, as well as during wake time in a very subtle manner without distracting the subject from their primary activity. This offers novel opportunities for interfaces and applications that extend from wake to sleep time. Research has shown that olfactory stimuli during sleep can significantly increase deep sleep and sleep quality as well as improving self-reported mood and positive content of dreams. Moreover, when a scent is paired with a learned material during the day and reactivated at night (Targeted Memory Reactivation) it has been shown to improve memory consolidation. We have also shown that by pairing scent with a VR experience, we can significantly increase subjective relaxation rates and relaxation scores associated with alpha and theta brain frequencies.
We developed novel wearables, concepts, software, and designs that improve considerably on state of the art olfactometers. In comparison with previous scent delivery systems used for sleep studies, our prototype is more than 40 times lighter and 700 times smaller. Current scent technologies used in sleep laboratories are not portable and require the use of nasal masks, large olfactometers, and a minimum of 22 wire attachments to track physiological information. As a result, current technologies are not suitable for mobile, day-time applications or home usage by non-technical users. We designed, built and successfully deployed scent technologies that can release scent based on physiological or context-based information and can be worn during the day and re-activated at night. We have also used these devices to perform the first home-based scientific experiments of scent-delivery for Targeted Memory Reactivation and improvement of sleep quality, and have opened up the opportunity for sleep scientists to do in the wild studies.