He said, she said: episodic retrieval induces conflict adaptation in an auditory Stroop task

People respond more slowly if an irrelevant feature of a target stimulus is incompatible with the relevant feature or the correct response. Such compatibility effects are often reduced in trials following an incompatible trial, which has been taken to reflect increased cognitive control. This pattern holds only if two trials share some similarities, however, suggesting that it may be modulated by the episodic context. To look into this possibility, we had participants respond to high- or low-pitched tones by saying "high" or "low," respectively, and ignore the simultaneously presented auditory word "high" or "low." As expected, performance was impaired if the heard word was incompatible with the required response, and this Stroop-like effect was reduced after incompatible trials. This sequential modulation was observed, however, only if the voice in the two successive trials was the same, whereas no modulation was obtained when the speaker changed. The results suggest that sequential modulations are due to the automatic retrieval of episodic event representations that integrate stimuli, actions, and situational and task-specific control information, so that later reactivation of some elements of a given representation tends to retrieve the other elements as well.