Evaluating the Effect of Semantic Congruency and Valence on Multisensory Integration.

Previous studies have found that semantics, the higher-level meaning of stimuli, can impact multisensory integration; however, less is known about the effect of valence, an affective response to stimuli. This study investigated the effects of both semantic congruency and valence of non-speech audiovisual stimuli on multisensory integration via response time (RT) and temporal-order judgement (TOJ) tasks [assessing processing speed (RT), Point of Subjective Simultaneity (PSS), and time window when multisensory stimuli are likely to be perceived as simultaneous (temporal binding window; TBW)]. Through an online study with 40 participants (mean age: 26.25 years; females = 17), we found that both congruence and valence had a significant main effect on RT (congruency and positive valence decrease RT) and an interaction effect (congruent/positive valence condition being significantly faster than all others). For TOJ, there was a significant main effect of valence and a significant interaction effect where positive valence (compared to negative valence) and the congruent/positive condition (compared to all other conditions) required visual stimuli to be presented significantly earlier than auditory stimuli to be perceived as simultaneous. A subsequent analysis showed a positive correlation between TBW width and RT (as TBW widens, RT increases) for the categories that were furthest from true simultaneity in their PSS (Congruent/Positive and Incongruent/Negative). This study provides new evidence that supports previous research on semantic congruency and presents a novel incorporation of valence into behavioural responses.