세부특징부재 탐색과제에서 네-점 차폐와 역행패턴 차폐가 표적 변별에 미치는 영향

초록

When two stimuli are briefly displayed in sequence at a location in the visual field, backward masking, in which identification of the preceeding stimulus is hindered by a subsequent mask stimulus, is induced. This study aimed to test the object-substitution hypothesis (Enns & Di Lollo, 1997, 2000) recently proposed for the mechanism of backward masking by observing the effect of four-dot and pattern-backward masking on target identification in a feature-absent search. Experiment 1 and 2 combined feature-absent search in which a target without a Vernier offset is searched after and multiple-masking paradigms to prevent immediate attention to a salient mask, and thus minimized target recognition errors by spatially focused attention onto a subsequent pop-out mask. The drop of target identification accuracy by increasing number of displayed items (setsize effect) was more evident as a mask-offset delay increases under the four-dot masking and as a mask-onset delay decreases under the pattern-backward masking respectively. The results indicate that both visual masking may occur due to object-substitution during a perceptual processing stage rather than a post-perceptual attentive or than a sensory interaction stage.

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