Symbolic- and response-related contributions to blindness to compatible stimuli

Blindness to compatible stimuli refers to poorer target identification (e.g., right-pointing arrowhead) following compatible stimuli (e.g., right arrows; Stevanovski, Oriet, & Jolic?ur, 2003) and compatible responses (e.g., right key press; Müsseler & Hommel, 1997a and 1997b). To clarify the role of the response in this effect, we examined the impact of adding or removing an overt response. In three experiments, subjects saw an arrow cue (that sometimes required a response) followed by a brief, masked arrowhead, which was reported on all trials. In all experiments, making a response increased the magnitude of the blindness effect. Furthermore, “no response” performance was unaffected by whether subjects had previously responded to the cue. Results favour a two-factor symbolic- plus response-related activation model over a purely symbolic activation model.