Suppressing Distractors, Enhancing Targets: Template Tuning in Ensemble Perception

AbstractEnsemble perception is a fundamental mechanism enabling the visual system to rapidly extract summary statistical properties (e.g., mean orientation) from a large number of objects. This study investigated the influence of attentional templates for targets and distractors which are formed during visual search, on subsequent ensemble perception. Participants first completed a visual search task involving target and distractor colors, followed by an ensemble orientation estimation task in which these colors recurred in various combinations. The first experiment revealed that target template systematically biased ensemble estimates, with the strongest effect occurring when both template colors recurred together. Furthermore, on these trials the bias exceeded the sum of the individual effects of target and distractor conditions, which demonstrates that combined effect of target enhancement and distractor suppression may be greater than predicted by their individual effects. In the second experiment, presentation duration (150 ms vs. 500 ms) was manipulated. While our results showed that duration did not alter the magnitude of the biases, a longer presentation time improved response precision. These findings suggest that ensemble perception can be modulated by recently formed attentional templates and systematically shape the formation of summary statistical representations.