Abstract
We investigated whether or not the compatibility effect (CE) in a trial block is modulated by conflict frequency in a block-level. In our experiment, right-handed eighty participants were given the Eriksen-type flanker task in which they were identified a center letter (target; “X” or “N”) among 5-letter strings (e.g., “XXXXX”, “XXNXX”) that were briefly presented to a left or right visual-field. The participants were randomly assigned to the five groups of 16 participants in which the compatibility ratio in a block-level was 17%, 25%, 50%, 75%, and 83%, respectively. Also, we manipulated the compatibility between the target and the noise letters. Results showed that the CE was greater as the compatibility ratio was larger. These findings suggested that visual selectivity is modulated by a linear function of the compatibility ratio in a trial block.
