Attentional sampling resolves competition along the visual hierarchy

Navigating the environment involves engaging with multiple objects, each activating specific neuronal populations. When objects appear together, these populations compete. Classical attention theories suggest that selection involves biasing one population over another. Recent research shows that perception fluctuates over time at ~8 Hz for single-object attention and 4 Hz for two-object attention, possibly because of the division of the 8-Hz rhythm between competing objects. This opinion surveys these fluctuations, coined ‘attentional sampling,’ across the visual hierarchy. We propose that sampling is a selection mechanism that negotiates neuronal competition. It manifests as early as eye channels and extends to complex features higher in the visual hierarchy. We discuss the cognitive significance of this mechanism and its potential neuronal implementation.