Repetition or alternation of context influences sequential congruency effect depending on the presence of contingency.

The sequential congruency effect (SCE) is defined as the decrease in the congruency effect following incongruent trials compared to congruent trials. The effect of context repetition on the SCE was investigated in four experiments. In all the experiments, dynamic visual white noise was used as the contextual feature, and the number of congruent and incongruent trials was equal. In Experiments 1 and 2, by using eight-value Flanker and Stroop tasks, and excluding stimulus- and response-feature repetitions from the analysis, a SCE was observed in both context repetition and alternation conditions. In Experiment 3, using a two-value Flanker task, all trials consisted of stimulus- and response-feature repetitions, and a SCE was only observed in the context repetition condition. In Experiment 4, we used a four-value Flanker task, which enabled half of the trials to be partial/complete repetitions and the other half to be complete alternations. A SCE was observed in both context repetition and alternation conditions irrespective of the stimulus- and response-feature repetitions. This pattern of results suggested that the effects of context repetition on the SCE are subject to a number of factors including stimulus- and response-feature repetitions and contingency biases. When contingency information exists, the presence of stimulus- and response-feature repetitions was no longer effective in yielding effects of context repetition on the SCE. These findings suggest that the usage of information registered in episodic event representations including stimulus-, response- and contextual-features, control parameters and contingency biases results from interactions of a complex pattern of mechanisms, yet to be further explored.