抄録
A number of studies have demonstrated that congruency effect observed by stimulus-response compatibility paradigm depends on proportion congruency (PC) in an experimental block (e.g., Gratton, Coles, and Donchin, 1992). More specifically, the congruency effect becomes larger in high PC block in which the congruent trials appear frequently (e.g., 75 %) than that in low PC block (e.g., 25 %), which is named Proportion Congruency (PC) effect. The purpose of the present study was to investigate the generality of PC effect between two presentation locations (close/far). We gave 16 university students the spatial-Stroop task which required to identify a Kanji stimulus ("UE" or "SHITA" means "up" or "down" respectively.) which was presented at one of four possible locations (two upper and two lower positions across the fixation point). We focused on the Stroop-like effect (congruency effect) which denotes the performance deterioration in the incongruent trials in which the identity of the target ("up" or "down" is incompatible with the presentation location (upper or lower from a fixation), compared with the congruent trials. Important manipulation was the PC at the close/far locations from a fixation point. For example, PC at the close locations was manipulated with 75 % or 25 % (the varied PC location), whereas PC at the far locations kept 50 % (the constant PC location). The results showed that the modulation of congruency effects associated with block-wise PC (75 %/25 %), i.e., PC effect, appeared in the constant PC location as well as in the varied PC location, suggesting that the modulation of congruency effect according to PC generalizes between the two different locations when the stimuli are common between them.
