Emotional and hemispheric asymmetries in shifts of attention: an ERP study.

Inhibition of return (IOR) refers to the larger response time to cued targets appearing at long cue-to-target intervals. Given emotion-attention interactions and associated visual field (VF) asymmetries, we examined the effects of emotions and hemispheric processing on object- and location-based IOR. We expected reduced IOR and right hemispheric bias accompanied by differences in event-related potentials (ERPs) including lack of suppression of cued N1 and enhancement of Nd components for sad targets. Reaction times and ERPs were recorded in an exogenous cuing detection task using happy and sad schematic faces. Results revealed reduced IOR for left compared to right VF with sad faces but no such asymmetry for happy faces. Cued N1 amplitudes were suppressed for happy targets but not for sad targets presented to the left VF. Nd amplitudes were enhanced for right-hemispheric sad faces especially with object-based IOR. The results indicate right-hemispheric advantage in the capture of attention by negative emotion especially with object-based selection.