A Simon effect for stimulus-response duration

A non-spatial variant of the Simon effect for the stimulus-response (S-R) feature of duration is reported. In Experiment 1 subjects were required to press a single response key either briefly or longer in response to the colour of a visual stimulus that varied in its presentation duration. Short keypresses were initiated faster with short than with long stimulus duration whereas the inverse was observed with long keypresses. In Experiment 2 subjects were required to press a left or right key (according to stimulus form) either briefly or longer (according to stimulus colour). The stimuli concurrently varied in their location (left or right) and duration (short or long), which were both task irrelevant. Approximately additive correspondence effects for S-R location and S-R duration were observed. To summarize, the results suggest that the irrelevant stimulus features of location and duration are processed automatically and prime corresponding responses in an independent manner.