Effects of Perceptual Load and Working Memory On a Simon Task

Event Center A&B

According to Perceptual load (PL) hypothesis PL is one of the determining factors of attentional selection. A variation of the Erikson flanker task is generally used for PL tasks, but the Simon task is another interference task. In the Simon effect reaction times are shorter for targets presented on the same side as the response, despite the target location being irrelevant. Working memory (WM) content has also been shown to capture attention in previous research. Therefore the relative effectiveness of attentional selection between PL and WM in a Simon task was investigated. A compatibility effect for the LPL condition, but not for the HPL condition was expected. Participants (n=15) were asked to keep the location of an item in memory, perform a letter discrimination task with varied PL, and answer if an item was in the same location as the memory item. The three levels of PL were no PL (target alone) which is a typical Simon task, LPL (three homogenous distractors: O), and HPL (three homogenous distractors: V, T, K). Accordingly the design was a 3 (no PL, LPL, HPL) X 2 (Memory: same, different), X 2 (compatible, incompatible) within participant design. Results showed a Simon effect for HPL, when the memory and target location matched, which is consistent with the attention shift model of the Simon effect. However, when the memory and target locations did not match there was Simon effect only for the no PL condition, due to how well targets popped out during a visual search.