Belmont SURFS

Can you HAND-le these emotions? An investigation on hemispheric dominance when viewing emotional faces.

Understanding dominant handedness has important clinical implications for surgery and patient groups like stroke (Agarwal, 2016; Harris & Eng, 2006). Predominantly, right-handers present left-hemisphere language dominance (Knecht, 2000) while left-handers often present as bilateral or right dominant (Bidula, 2017). Hemispheric lateralization of function also extends to other cognitive domains, such as emotional processing, where there are 2 major theories. The valence lateralization hypothesis, looking at positive or negative emotional qualities, suggests left hemispheric dominance for positive emotions and right dominance for negative ones (Palomero-Gallagher, 2022). The approach-withdrawal hypothesis, explaining motivational behavior associated with emotions, suggests left hemispheric dominance for approachable emotions and right dominance for withdrawal emotions (Davidson, 1990). Similar to language hemispheric dominance, emotional processing may be lateralized in the brain according to handedness. The current study aims to better understand this emotional hemispheric lateralization, in conjunction with handedness. We hypothesize that right-handers will show higher functional activity in the left hemisphere for positively-valenced and approachable facial stimuli. The summer research sessions involved the creation and piloting of a novel forced-choice facial emotion judgement task, developed for an infrared neuroimaging environment (https://nirx.net/). Findings from this study, which will run in the fall, may impact clinical groups experiencing emotional deficits after a neural assault and/or degeneration and may better guide targeted interventions.

Keywords: Infrared imaging, neuroimaging, affective neuroscience, emotions, handedness, brain laterality