Competition and selectivity in the visual system: evidence from event-related brain potentials

Visual attention;Visual search;N2pc;Event-related potentials;Biased competition

Hilimire, Matthew R ; Psychology

University:Georgia Institute of Technology

Department:Psychology

关键词: Visual attention;    Visual search;    N2pc;    Event-related potentials;    Biased competition;   

Others  :  https://smartech.gatech.edu/bitstream/1853/43664/1/hilimire_matthew_r_201205_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

When multiple objects are present in a visual scene, salient and behaviorally relevant objects are selectively processed at the expense of less salient or irrelevant objects.Here I used three lateralized components of the event-related potential â " the N2pc, Ptc, and SPCN â " to examine how objects compete for representation in our limited capacity visual system, and how task-relevant objects are selectively processed.Participants responded to the orientation of a color singleton target while ignoring a color singleton distractor.Competition between the objects was manipulated by presenting visual search arrays that contained only a target, only a distractor, or both objects together. In Experiment 1, observers did not know the color of the target in advance, whereas in Experiment 2 this information was provided. Experiment 3 was a control experiment to rule out low-level sensory explanations of the effects.The results suggest that the N2pc component indexes capture of attention by salient objects which is modulated both by competition between the objects and top-down knowledge.The Ptc component may index inhibition of return so that once an object is processed it is not selected again.The SPCN component may index enhancement of goal-relevant objects once task-irrelevant objects have been suppressed.Together these lateralized event-related potentials reveal the temporal dynamics of competition and selectivity in the human visual system.