Abstract
Face recognition is critically dependent on configural and holistic processing. The present study examines the extent to which configural face processing is under top-down cognitive control using a novel dual-task paradigm in which forty participants concurrently engage in a face discrimination task and a motor task. In the Le Grand composite face discrimination task (Le Grand et al., 2004), the participants were instructed to report if the upper halves of two sequentially presented composite-face stimuli were the same or different in face identity while ignoring the consistently same bottom halves. The composite face effect (CFE) manifested as higher task performance when top and bottom halves of each face were misaligned than when properly aligned, indicating more interference (and hence more holistic face encoding) in the discrimination of top face halves by bottom face halves. Critically, the concurrent physical effort, operationalized as 45% of the maximal voluntary contraction (MVC) versus 5% MVC exerted on an isometric hand dynamometer by individual participants, led to significantly larger CFE in accuracy, presumably due to reduced inhibition of the bottom halves of face stimuli. In contrast, the overall face recognition ability assessed using the Glasgow Face Matching Task (GFMT; Burton, White, & McNeil, 2010) showed no significant effect of the concurrent physical load. Together, these results provide further support for impairment in inhibitory control under concurrent physical effort, in line with our previous demonstrations of reduced cognitive control by concurrent physical effort (Azer et al., 2019, VSS; Cappiello et al., 2018, VSS). Follow up studies will investigate the effect of concurrent physical effort on global verses local processing in visual perception beyond face processing.