Bad after bad is good: previous trial disfluency reduces interference promoted by incongruence.

Conflict and perceptual disfluency have been shown to lead to adaptive, sequential, control adjustments. Here, we propose that these effects can be additive, suggesting their integration into a general feeling of disfluent information processing. This hypothesis was tested using an interference task that dynamically mixed trials varying in legibility and/or congruence. Moreover, the manipulation of the proportion of congruent trials within the task allowed differentiating conditions in which these experiences of fluency may vary. Results showed that progressive increases in processing disfluency elicited a matching decrease in the interference of incongruent fluent trials. This linear effect was significant for all proportion of congruence conditions, although lower when incongruent trials were more frequent. These results highlight the role of feelings in the initiation of control and suggest that the monitoring system could be using changes in information processing fluency as a need-for-control signal.