title: Pupil-size asymmetry is a physiologic trait related to gender, attentional function, and personality.
abstract: A small difference in the size of the two pupils is common in healthy individuals, a condition termed benign or physiologic anisocoria (BA). Past research indicates that BA is probably caused by asymmetry in sympathetic nervous system (SNS) function [e.g., Rosenberg (2008). Physiologic anisocoria: A manifestation of a physiologic sympathetic asymmetry. Neuro-Ophthalmology, 32, 147-149]. This study is the first to show that BA varies with psychological factors linked to brain asymmetry and autonomic arousal, including gender, attention, and personality. Males exhibited a more directional BA than females, consistent with greater hemispheric lateralization in males. BA also varied with a self-report measure of attentional function, consistent with evidence of hemispheric asymmetry in visuospatial attention networks. Finally, BA varied with personality traits linked to autonomic arousal. Individuals exhibiting higher Meanness and Boldness, and lower Empathy scores tended to show more directional BA. This link between personality traits and BA may be related to brain asymmetries in autonomic arousal and emotion-related processing. If future studies employing direct measures of lateralized brain activity confirm the link between BA and SNS asymmetries, this new metric may prove useful in discovering new relationships between brain organization and psychological function, and how these relationships vary across individuals.
authors.affiliation: a Psychology Department , Western Carolina University , Cullowhee , NC , USA.
authors.forename: William D
authors.initials: WD
authors.lastname: Poynter
mesh_terms: D000293:Adolescent; D000328:Adult; D015875:Anisocoria / Q000503:physiopathology / Q000523:psychology*; D001143:Arousal / Q000502:physiology; D001288:Attention / Q000502:physiology; D053483:Eye Movement Measurements; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010551:Personality / Q000502:physiology; D011680:Pupil; D057566:Self Report; D012727:Sex Characteristics; D055815:Young Adult
keywords: Pupil size; anisocoria; asymmetry; attention; autonomic function; lateralization; personality; sex differences