Activation of response codes by relevant and irrelevant stimulus information

Single-route models attribute stimulus-response compatibility effects to the difficulty of translation from stimulus to response. Dual-route models propose that compatibility effects reflect in part an additional direct, or automatic, activation route. Selected findings from three lines of research are reported that converge to provide evidence consistent with the view that the automatic activation route plays a role in compatibility effects. The data suggest that the activation produced via this route by relevant stimulus attributes influences response selection only when all mappings of stimuli to responses are known to be compatible.