Examining the effect of visual stimuli on odor perception in cognitive mechanisms

The daily decisions we make are the result of numerous complex sensory interactions; from how the colors we see alter our perception of odors to how restaurant menu design influences our food preferences. This research aims to understand how the brain integrates visual, olfactory, and cognitive information, and how this integration influences human behavior. Through three studies, it investigates in depth: (1) the different neural effects of lexical and color cues on odor naming performance and changes in brain connectivity networks, (2) how colors modulate our odor preferences and the role of cross-modal interactions in preference formation, and (3) how visual stimuli beyond odor and taste perception affect food choice behavior in the context of traditional Turkish cuisine and how they can guide healthy eating preferences. Study 1 conducted EEG recordings during an odor naming task using lexical and color cues with 40 Turkish-speaking participants. Directed functional connectivity patterns between brain regions were examined through Granger causality analysis. Study 2 investigated color-odor preference interactions with the same participant sample through behavioral ratings and EEG connectivity analysis across three experimental sessions. Study 3 investigated the visual decoy menu effect on food choices using visual presentations of traditional Turkish cuisine dishes, combining online and eye-tracking methodologies to measure the effects of visual stimuli on choice patterns and visual attention distribution. Study 1 demonstrated odors are better identified when preceded with lexical cues compared to color cues. Color cues activated the majority of electrode connections (97.4%) demonstrating strong frontal-occipital connectivity, while lexical cues activated less connection (67.1%) with focused frontal-temporal circuits. Study 2 showed systematic cross-modal modulation effects, such that when odors were preceded by color presentations, there was an overall significant change in liking. For disliked odors, presenting liked colors led to the strongest increase in ratings. Within and between regions connectedness of the prefrontal hub was highest among other areas during color-odor integration. Study 3 confirmed significant decoy effects of visual menu design on food choice behavior. The non-meat menu selection increased from 26.27% to 29.76% in the presence of a high-priced decoy menu visual presentation. Eye-tracking data revealed systematic attention patterns, indicating that participants initially focused on the visually presented main meat courses (41%), regardless of their final choices. Main course visuals attracted more visual attention compared to price and side dish areas. These findings demonstrate that multisensory integration operates through distinct neural mechanisms, depending on the cue type and baseline preferences. The research reveals both facilitatory and inhibitory cross-modal effects, providing practical implications for understanding consumer behavior and the modulation of preferences. The systematic nature of these interactions suggests that multisensory processing follows predictable patterns that can be utilized in applied contexts, ranging from product design to behavioral interventions that support healthier food choices.