Inhibition Effect of Spatial Attention on Surroundings in Discrimination Task

Abstract

The cue size effect which is characterized as a reverse relationship between the cue size and the detection speed is regarded as a proof for adjustment of the attentional field according to the cue size. This effect was mainly found in detection experiments. As several studies have shown that cues had discrepant effects in visual detection and discrimination task, it's natural to ask whether cue size effect still exist in discrimination task. The probability exists that the influence of cue size differ in these two basic types of behavioral tasks. To solve the problem, we assessed the interference of surrounding ring on discrimination at its center with a multiple cuing design. The results show that in distributed neutral condition when no single place gains overwhelming advantage from attention, ring size has a positive correlation with the discrimination speed. However, when the exact place of impending target is cued and spatial attention takes effect, variance in surrounding ring size makes no difference on discrimination. This type of result pattern doesn't depend on what is discriminated (orientation or brightness) or how the spatial attention is induced (by peripheral ring cue or central symbolic line cue). Our findings add evidence to the view that detection and discrimination should not be considered as the same. We also propose that with sufficient time, attention suppresses the impact from the vicinity.