Effects of attention on a relative mislocalization with successively presented stimuli.

Previous studies yielded evidence that the precision, with which stimuli are localized in the visual periphery, is improved under conditions of focused attention. The present study examined whether focused attention is able to correct a mislocalization recently observed with successively presented stimuli: when observers are asked to localize the peripheral position of a briefly presented target with respect to a previously presented comparison stimulus, they tended to judge the target as being more towards the fovea than was its actual position. In three experiments the mislocalization was tested under conditions with focused and distributed attention. Results revealed that the mislocalization increased with distributed attention and disappeared when stimuli appeared consistently at predictable positions and thus under conditions of focused attention. However, when a procedure with a trial-by-trial cueing was applied the mislocalization was only reduced, but not wiped out completely. In a recently developed dynamic field model consisting of interacting excitatory and inhibitory neuronal cell populations the results were explained as an attentional modulation of spontaneous (baseline) levels of neural activity.