Strategical determinants of compatibility effects with task uncertainty

Three experiments were conducted to investigate why effects of stimulus-response compatibility (SRC) disappear when the mapping rule is varied randomly and provided only briefly before the imperative stimulus arrives. Three alternative explanations were tested by manipulating automatic response priming, relative probabilities of the mappings, and degree of interference or crosstalk between the mappings. The results indicate that the reduction of SRC effects reflects an active initial suppression of the compatible mapping rule. This suppression appears to be necessary in order to prevent the compatible rule from producing detrimental interference when the incompatible rule is called for instead. These results demonstrate the important role of strategical factors in regulating performance in dynamic task settings.