Smell-O-Message: Integration of Olfactory Notifications into a Messaging Application to Improve Users' Performance

Smell is a powerful tool for conveying and recalling information without requiring visual attention. Previous work identified, however, some challenges caused by user's unfamiliarity with this modality and complexity in the scent delivery. We are now able to overcome these challenges, introducing a training approach to familiarise scent-meaning associations (urgency of a message, and sender identity) and using a controllable device for the scent-delivery. Here we re-validate the effectiveness of smell as notification modality and present findings on the performance of smell in conveying information. In a user study composed of two sessions, we compared the effectiveness of visual, olfactory, and combined visual-olfactory notifications in a messaging application. We demonstrated that olfactory notifications improve users' confidence and performance in identifying the urgency level of a message, with the same reaction time and disruption levels as for visual notifications. We discuss the design implications and opportunities for future work in the domain of multimodal interactions.