Mapping symbols to response modalities: interference effects on Stroop-like tasks.

Response compatibility effects were assessed with a Stroop-like task which involved arrow and word stimuli. The subjects were required to respond to one stimulus--an arrow (e.g.,-->) or a word (e.g., left)--and ignore the other. It was shown that response compatibility played a significant role in generating Stroop-like interference. Robust interference effects were observed when the subjects responded manually to word stimuli (ignoring irrelevant arrows) and when they responded vocally to arrow stimuli (ignoring irrelevant words). Smaller interference effects were observed under response-compatible conditions, namely, responding manually to arrows and vocally to words. In the second experiment, within-dimension displays (e.g., arrow-arrow or word-word displays) yielded a pattern of interference that did not interact with response modality. These findings indicate that both stimulus-response compatibility effects and target-distractor similarity are crucial for understanding Stroop-like interference.