Scent of Emotion: Investigating cross-modal associations between smell, sound, and vision and their impact on emotional processing across the lifespan

Secondary Supervisor(s): Dr Anna Kowalczyk

University of Registration: University of Birmingham

BBSRC Research Themes: Understanding the Rules of Life (Neuroscience and Behaviour)

Project Outline

Multisensory experiences are an intrinsic part of how we perceive the world around us, with smells having a particularly strong ability to trigger emotions and vivid memories. Smells are deeply connected to memory and emotion, often eliciting feelings that appear instantly and unconsciously. However, while the emotional power of odours is well-documented, there is less research exploring how these olfactory cues interact with other sensory modalities, such as auditory and visual stimuli. The current project aims to explore the under-researched territory of cross-modal correspondences between smell, sound, and vision and their emotional impact, providing new insights into how multisensory experiences are processed in the brain.

Using an interdisciplinary approach combining behavioural testing, neuroimaging, and eye tracking, this project will examine how specific smells are associated with characteristics of sound and visual features. For instance, vanilla scents may correlate with soft sounds and rounded shapes, while lemon scents might be more closely tied to high-pitched, sharp tones and angular forms. Importantly, these sensory associations are believed to be linked to specific emotional responses, which we will assess across different age groups, including children, young adults, and older adults. The project will employ both functional and structural neuroimaging techniques, primarily Optically Pumped Magnetometers (OPM-MEG), which offer unparalleled temporal resolution and non-invasive monitoring of brain activity. By using OPM-MEG, we can observe the responses of brain regions responsible for processing multisensory information and emotional regulation, with a particular focus on intersensory connections.

Behavioural measurements will explore participants' subjective emotional responses to cross-modal stimuli, while eye-tracking data (saccade, microsaccade and gaze behaviour) will provide insights into how attentional processes are engaged during these experiences. Neuroimaging, combined with advanced statistical approaches such as multivariate information theory and machine learning decoding techniques, will target key regions like the orbitofrontal cortex, hippocampus, and amygdala, as well as frontal areas involved in cognitive control and top-down processing. Using OPM-MEG’s unique capability to record neural oscillations with high temporal precision, we will investigate the role of brain networks in temporal coordination of these sensory integration. This allows us to explore how emotions and memories triggered by olfactory stimuli influence cross-sensory associations and how cognitive strategies are engaged across age groups.

Moreover, the study will compare the responses of children, younger and older adults, contributing to our understanding of how age impacts sensory processing and cognitive control. Older adults may exhibit altered multisensory integration due to age-related changes in sensory systems and brain structures, particularly in frontal regions associated with higher-order cognitive functions. Understanding these mechanisms will help develop strategies to create emotionally supportive environments across the lifespan, particularly in home and school settings for children, including those in neurodiverse populations. This research will also open new avenues for therapeutic interventions, particularly in emotional and mental health treatments. The potential for using specific odour and sound combinations to influence emotional states could have applications in anxiety, depression, and stress-related disorders. Ultimately, this work could inform new strategies in sensory therapy, where controlled multisensory experiences are harnessed to promote mental well-being.

References

Aydemir O (2017) Olfactory Recognition Based on EEG Gamma-Band Activity. Neural Comput 29:1667-1680.

Spence C (2020) Olfactory-colour crossmodal correspondence in art, science, and design. Cogn Res 5.