Abstract
We used a modification of Eriksen and Eriksen's (1974) flanker interference task, to assess the effects of spatial attention on choice reaction time (RT) to one of two probe stimuli that followed two flanking stimuli by 53 ms. Separate response keys were assigned to each probe. The probes and flankers consisted of outlined squares or diamonds. In the response-compatible condition, flankers' shapes were identical to that of the probe; in the response-icompatible condition, they were different from that of the probe. In Experiment 1 we established, as expected, that RTs are higher in the response-incompatible than in the response-compatible case. In Experiment 2 revealed two additional findings. 1) The differences between probe RTs when preceded by response-incompatible and response-compatible flankers decreased as the center-to-center spatial separation between the probe and flankers increased from 2° to 12°, indicating, in line with Erisksen and Eriksen's (1974) findings, that the effect is limited by the spread of spatial attention. 2) This trend occurred even when the flankers were rendered invisible by a metacontrast mask, indicating that spatial attention effects are expressed at the nonconscious level of flanker processing.
riksen, B. A., & Eriksen, C. W. (1974). Effects of noise letters on the identification of a target letter in a nonsearch task. Perception & Psychophysics, 16, 143–149.