Is attention really biased toward the last target location in visual search? The role of focal attention and stimulus-response translation rules

There is considerable confusion in the visual attention literature as to whether shifts of attention are biased against or in favor of previously attended regions. Studies requiring target localization have shown a performance cost when the target location randomly repeats instead of changes, whereas studies requiring arbitrary keypress responses to target identities have shown a benefit. These studies differ in the amount of attention required to the target and in the stimulus-response translation rules. To evaluate the contribution of each of these factors in accounting for the mixed results, we had participants indicate whether color singletons appeared in the left versus right visual field, or in the upper versus lower visual field, by making spatially compatible keypress responses (a between-experiment manipulation of the stimulus-response translation rules). Within each experiment, we manipulated whether a subtle discrimination of shape was necessary before localizing the target (a manipulation of focal attention). The findings revealed that the costs and benefits for repeating the target location are determined by stimulus-response translation rules, with no effect of or on attention independent of these rules. The results are accounted for by the theory of event coding, and further challenge the notion that location repetition effects reliably reflect attentional bias.