Cognitive control mechanisms in the “micro-” and “macro” sequence effects

In the typical Simon task, responses to a non-spatial stimulus feature (e.g. color) are faster and more accurate when stimulus and response spatially correspond (C trials) than when they do not correspond (NC trials). It has been recently shown that when participants perform a spatially-incompatible task before performing the Simon task, the Simon effect (that is, the advantage of corresponding trials) disappears (“macro” effect). In a similar way but within the same task, the effect is null or inverted after a NC trial (“micro” effect). Aim of the present work was to test whether the “macro” effects are generated by the same cognitive mechanisms responsible for the “micro” effects.
Thirty-two subjects took part in the study. Half of them performed a Simon task alone, while the other half performed a spatially incompatible task, followed by a Simon task. We assessed the influences on processing of the current Trial N of events occurring in trials N-1 and N-2.
Our results suggest the presence of a common cognitive control mechanism which selects the stimulus-response link which will be activated trough the unconditional route and modulates the flaw of activation of this route according to the preceding type of trial.