Spotting from The Rightmost Deep: A Temporal Field Advantage in A Behavioural Task of Attention And Filtering

During the past decades, animal and human physiological studies have suggested that subcortical structures that are part of the extrageniculate pathways have an important role to play in the attentive selection of targets and the filtering of distractors. However, not much has been done to investigate the filtering of distractors in purely behavioural experiments through cues that might reveal extrageniculate functions, such as the asymmetry in performance between the nasal and the temporal visual fields. Here, under monocular conditions, participants viewed laterally and tachistoscopically presented sets of visual stimuli and were required to decide whether a target was present in the set or not. The manipulation of attention demands was achieved by varying the degree of spatial organization of the stimuli. A temporal field advantage in detection accuracy was found, and was observed only for disorganised sets of stimuli, that is, when demands on attention were greater. Furthermore, this pattern was found only for stimuli projected to the right hemisphere. The results suggest that the extrageniculate pathways of the right hemisphere in humans are involved in filtering out distractors. They are discussed in light of findings and theories about extrageniculate mediation of selective attention