Reaction time is often shorter when the irrelevant graspable handle of an object corresponds with the location of a keypress response to the relevant attribute than when it does not. This object-based Simon effect has been attributed to an affordance for grasping the handle with the hand to the same side. Because a grasping affordance should…

Left-right keypresses to numerals are faster for pairings of small numbers to left response and large numbers to right response than for the opposite pairings. This spatial numerical association of response codes (SNARC) effect has been attributed to numbers being represented on a mental number line. We examined this issue in 3 experiments using a…

Four experiments examined transfer of noncorresponding spatial stimulus-response associations to an auditory Simon task for which stimulus location was irrelevant. Experiment 1 established that, for a horizontal auditory Simon task, transfer of spatial associations occurs after 300 trials of practice with an incompatible mapping of auditory …

Pigeons pecked left versus right keys contingent upon the color presented at 1 of those locations. Spatial-response latencies were shorter when the color appeared at the same location as the required response than at the opposite location. This Simon effect occurred when the stimulus on the alternative key was constant, varied from trial to trial,…

Stroop dilution is the reduction of the Stroop effect in the presence of a neutral word. It has been attributed to competition for attention between the color word and neutral word, to competition between all stimuli in the visual field, and to perceptual interference. Five experiments tested these accounts. The critical manipulation was whether…