Spatial characteristics of visual attention reflected in illusory conjunctions

In order to examine the shape of the spotlight of attention, dependence of illusory conjunctions on the stimulus configuration is investigated, based on the model that illusory conjunctions occur only if different stimuli exist simultaneously in the spotlight of attention. It was found, by experiment, that when the stimulus items were arranged along a line radiating from the fixation point, illusory conjunctions occur very frequently; when the items were arranged along a line perpendicular to the radiating line, illusory conjunctions occur less frequently. Based on the model of the static spotlight of attention, the obtained results indicate that the shape of the spotlight extends along the radiating line. Another explanation is that the attentional spotlight scans each item rapidly and the spotlight is ready to shift along the radiating line. The fact that features were incorrectly combined with a specific tendency can be explained more easily by the latter model