The effects of acute alcohol intake on endogenous vs. exogenous attention in visual perception.

Acute alcohol consumption is known to impair visual perception, yet the underlying mechanisms remain poorly understood. Visual perception is influenced by visual attention, which comprises two distinct components: endogenous (voluntary) and exogenous (involuntary) attention. This study investigated how a moderate alcohol dose alters attentional modulation of visual perception. Participants performed an orientation discrimination task, reporting the tilt of a peripheral Gabor patch target. Valid, neutral, or invalid precues-central (endogenous) or peripheral (exogenous)-were presented to manipulate attention. Perceptual sensitivity was compared between alcohol-free and alcohol-intake conditions. Results revealed that alcohol spared endogenous attention's ability to enhance sensitivity at cued locations and reduce interference at invalidly cued locations. In contrast, exogenous attention's facilitatory effects at cued positions were impaired, while its effects at uncued locations remained intact. This dissociation indicates that endogenous and exogenous attention rely on distinct neural mechanisms, with alcohol selectively disrupting exogenous orienting. These findings clarify how alcohol impairs visual perception and underscore the importance of differentiating attentional subsystems in neurocognitive studies.