Can you still HAND-le these emotions? A continued investigation on hemispheric dominance with exposure to visual stimuli.

Poster Session A - Saturday, April 13, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Siena DeAngelo¹ (siena.deangelo@bruins.belmont.edu), Youstina Tadros¹, Hannah Potts¹, Savannah Campbell¹, Carole Scherling, PhD¹; ¹Belmont University

Similar to language, emotional processing may be lateralized in the brain according to handedness. Right-handers predominantly present left-hemisphere language dominance (Knecht, 2000), while left-handers show more variable laterality (Bidula, 2017). Furthering the literature on hemispheric dominance, emotional processing mechanisms have been suggested through two theories. First, the right-hemisphere-hypothesis suggests that emotional stimuli are perceived more efficiently by the right hemisphere (Smith & Bulman-Fleming, 2005). Second, the valence-hypothesis suggests that positively-judged emotions are left dominant, while negatively-judged are right dominant (Palomero-Gallagher, 2021). The current study furthers our understanding of emotional hemispheric lateralization using fNIRS (https://nirx.net/). We hypothesize higher left PFC activity in right-handers during emotional judgments. Thirty-seven undergraduates (31=right) completed valence-judgements of happy, sad, anger, disgust and fear faces (FEVA) and a handedness inventory. Preliminary behavioral data did not reveal accuracy differences between right and left handers when judging facial valence (p>0.05) and each emotion-type revealed expected valence ratings (p<0.01). Imaging analyses revealed higher HbO levels for right-handers when completing valence-judgements for all 5 emotion types. This right dominance supports the Right Hemisphere Hypothesis (Borod, 1998). Meanwhile, left-handers revealed variable hemispheric dominance: right for sad/disgust, left for anger/fear, and bilateral for happy. Hence, handedness may modulate hemispheric dominance when judging emotional faces, with right and left handers revealing different hemispheric activity for happy, anger, and fear. Overall, there presents hemispheric lateralization of emotional facial processing, which may be modulated by handedness. Such findings inform affective research and develop clinical interventions and surgery planning.

Topic Area: EMOTION & SOCIAL: Emotion-cognition interactions