Abstract
Several recent studies have shown that physically nonsalient stimuli associated with value through reward learning may affect attentional selection. One of the prominent hypothesis is that reward learning converts a stimulus with a neutral representation into a salient, ‘wanted’ stimulus. In the current study we provide direct evidence for this hypothesis. During the training phase, observers searched for a red or green target among differently colored nontargets. On each trial, following a correct response, they received feedback indicating a monetary reward which for one of the two target colors was associated with a high reward and for the other color with a low reward. Subsequently, in the test phase, observers were asked to perform an unspeeded simultaneity judgment (SJ) task, in which they indicated whether two visual stimuli (i.e. the red and green from the training phase), presented on either side of fixation, were presented simultaneously or not. The results showed that in order for the two stimuli to be perceived as simultaneous, the stimulus that was associated with a low reward had to be presented before the stimulus that had been associated with a high reward. This result provides compelling evidence that reward changes the salience of the stimulus and thus the temporal order of the two stimuli. Note that the results can not be explained by a response bias.
Meeting abstract presented at VSS 2012