Observation of Conflict Triggers Conflict Adaptation

The conflict monitoring theory posits that the simultaneous activation of incompatible responses in the current trial leads to response conflict. Conflict occurrence signals to enhance attention to the target stimulus, reduce attention to distracting stimuli, and ultimately lead to conflict adaptation (i.e., reduced interference effect after conflict trials compared to nonconflict trials). However, this theory does not explicitly assume whether the involvement of response execution is necessary in the process of conflict occurrence. Research on the negative emotion theory suggests that even in the absence of response execution, incompatible response representations can induce conflict. Our present study aimed to provide direct behavioural evidence regarding whether conflict activated without response execution is sufficient to trigger conflict adaptation. In a word-colour Stroop task, this study employed the LOOK-to-DO transition design, in which participants refrained from responding in half of the trials (LOOK trials) and responded with key presses in the other half (DO trials). Across three experiments, we controlled for feature integration and contingency learning and manipulated the stimulus presentation duration in the previous trial. The results indicated a significant conflict adaptation effect in reaction time when the stimulus presentation duration was shorter in the previous trial. This finding suggested that in a confounding-minimal design with no response execution in the previous trial, conflict triggers control adjustments and leads to conflict adaptation. This finding aligns with and further elaborates on the original conflict monitoring theory by demonstrating that response execution is not a necessary condition for the generation of response conflict.