Behavioral/Cognitive Action and Perception Are Temporally Coupled by a CommonMechanism That Leads to a Timing Misperception

We move our eyes to explore the world, but visual areas determining where to look next (action) are different from those determining what we are seeing (perception).Whether, or how, action and perception are temporally coordinated is not known. The preparation time course of an action (e.g., a saccade) has been widely studied with the gap/overlap paradigm with temporal asynchronies (TA) between peripheral target onset and fixation point offset (gap, synchronous, or overlap). However, whether the subjects perceive the gap or overlap, and when they perceive it, has not been studied.We adapted the gap/overlap paradigm to study the temporal coupling of action and perception. Human subjects made saccades to targets with different TAs with respect to fixation point offset and reported whether they perceived the stimuli as separated by a gap or overlapped in time. Both saccadic and perceptual report reaction times changed in the sameway as a function of TA. The TAdependencies of the time change for action and perceptionwere very similar, suggesting a common neural substrate. Unexpectedly, in the perceptual task, subjects misperceived lights overlapping by less than100 ms as separated in time (overlap seen as gap).Wepresent an attention-perceptionmodelwith amapof prominence in the superior colliculus thatmodulates the stimulus signal’s effectiveness in the action and perception pathways. This common source of modulation determines how compe-tition between stimuli is resolved, causes the TA dependence of action and perception to be the same, and causes the misperception. Key words: attention; gap effect; model; saccades; superior colliculu