Accuracy of selective saccades depends on the configuration of a target and a distracter

This study examined the difference in averaging effect between the case in which the target (T) and the distracter (D) were in the same direction of the fixating point at different eccentricities (eccentricity-different condition) and the case in which T and D were in different directions (direction-different condition). As a result, the averaging effect was observed in both conditions when subjects were forced to make saccades with very short latencies (Experiment 2). However, the results mere different between the two conditions when the subjects made saccades with relatively long latencies (Experiment 1) or when they knew in advance the position at which T would be appearing (Experiment 3): The averaging effect was evidently decreased in the direction-different condition, while the effect was still observed in the eccentricity-different condition. This suggests that the process of selecting a target of the saccade works reflectively depending on the stimulus configurations and can be controlled by some top-down processes.<>