Mixing incompatible mapped location-relevant trials with location-irrelevant trials: effects of stimulus mode on the reverse Simon effect.

When location-relevant trials with an incompatible spatial stimulus-response mapping are mixed with location-irrelevant trials, responses on the latter trials are faster when stimulus and response locations do not correspond than when they do. Experiments 1 and 2 showed that this reverse "Simon effect" also occurs when the location information is presented verbally or symbolically on both location-relevant and location-irrelevant trials. The reversal was absent, however, in conditions of Experiments 1-3 in which the mode of presentation was different on the location-relevant trials than on the location-irrelevant trials. Experiment 4 demonstrated that differences in physical characteristics between the location-relevant and location-irrelevant stimuli were not sufficient to eliminate the reverse Simon effect. These findings imply that the short-term associations between stimulus location information and responses defined for the location-relevant task are relatively mode specific.