Further evidence for the role of mode-independent short-term associations in spatial Simon effects

We examined the conditions under which short-term associations between stimuli and responses can produce spatial Simon effects. On location-relevant trials, participants gave neutral responses (i.e., they uttered the nonsense syllable "bee" or "boo") on the basis of whether the presented word had the meaning of "left" or "right." On location-irrelevant trials, they gave the same responses on the basis of the color of left and right squares. Performance on the location-irrelevant trials was affected by the match between the irrelevant location information and the location to which the correct response was assigned on the location-relevant trials. Experiment 1 showed that this extrinsic Simon effect was found only when the words on the location-relevant trials came from two different languages. In Experiment 2, we found an extrinsic Simon effect even when participants only received instructions about how to respond on location-relevant trials but no such trials were actually presented. Our findings suggest that task demands determine whether short-term associations are mode specific or mode independent and confirm that such associations can be set up as the result of instructions only.