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Abstract:
The identification of a visual object is influenced by the
visual scene wherein it occurs. We investigated the nature and time
course of scene effects by collecting event-related brain
potentials (ERPs) and reaction times (RTs). Participants identified
objects that were either congruous (e.g. a pot in a kitchen) or
incongruous (e.g. a desk in a river) within a scene. As expected,
reaction times were faster for congruous than incongruous objects.
The earliest sign of reliable scene congruity effects in the ERPs
(greater positivity for congruous pictures between 300-500 ms) was
around 300 ms, suggesting that scenes do not affect the earliest
stages of perceptual processing in the neocortex. Both the
morphology and time course of the N390 scene congruity effect are
reminiscent of the N400 sentence congruity effect typically
observed in sentence context paradigms, suggesting a functional
similarity of the neural processes involved. Overall, our results
support theories that postulate that visual scenes do not
appreciably affect object identification processes before
associated semantic information is activated.
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