Time-out for conflict monitoring theory: Preventing rhythmic biases eliminates the list-level proportion congruent effect.

The proportion congruent (PC) effect is the observation that congruency effects are smaller when most trials are incongruent rather than congruent. The list-level PC (LLPC) effect is the finding that a PC effect can transfer from biased inducer items to unbiased diagnostic items. Such effects are generally interpreted as resulting from conflict monitoring and attentional adaptation. An alternative view proposes that PC effects result from simple learning biases unrelated to conflict. The temporal learning account proposes that LLPC effects stem from a different task rhythm in the mostly congruent and mostly incongruent conditions. Two prime-probe experiments provide a critical test of this notion. In both, half of the participants were forced to withhold responding for a short period of time on inducer trials. This equates the task rhythm in the mostly congruent and mostly incongruent lists, while still maintaining differing levels of conflict. Consistent with the temporal learning account, but inconsistent with the conflict monitoring account, the LLPC effect was eliminated when rhythms were equated. (PsycINFO Database Record