Colour - Coded Scents: Crossmodal Perception In Complex Fragrances Mixtures

This work forms part of a broader investigation into how colour influences odour perception. In each study, cis-3-hexenol is paired with a different odour molecule, using both equal and varying intensity combinations to examine the impact of colour cues on olfactory experience.

Fragrance is a central element in cosmetic product design, known for its power to evoke emotion, trigger memory, and enhance user experience. As multisensory design gains prominence, colour is increasingly used not only for aesthetics but also as a perceptual cue that can influence how a scent is experienced.

Crossmodal research has shown that specific colour–odour pairings—such as yellow with sweetness or green with freshness—can amplify or attenuate odour intensity depending on their semantic congruence. However, most existing studies focus on single aroma compounds or static pairings, with limited investigation into more complex, dynamic scent systems.

This study addresses that gap by exploring how colour modulates odour perception in binary mixtures, particularly across varying aromatic ratios. Two molecules were selected to represent distinct olfactory roles:

Ethyl maltol (EM): sweet, caramel notes with broad receptor activation (e.g. OR1G1, OR5AN1), simulating a base note.
Cis-3-hexenol (Cis-3): a volatile, green/grassy compound with narrow specificity (OR2J3), simulating a top note.

Three aromatic ratios (1:1, 2:1, and 1:2) were tested to examine whether odour dominance influences colour–odour interactions. EM carries strong gourmand/sweet associations, while Cis-3 is linked to freshness and naturality, enabling exploration of both congruent and incongruent pairings. Although cultural and genetic factors were not directly tested, their relevance is acknowledged.

A three-phase experimental design, was employed.

The aim of this study was to investigate whether colour modulates perceived fruity/sweet intensity in binary fragrance mixtures of EM and Cis-3 at varying intensity ratios.