If it's hard to read… try harder! Processing fluency as signal for effort adjustments.

Experiencing difficulties during information processing can either be used as signal for the increased need of cognitive effort ("try harder"), or as avoidance signal for future action selection ("avoid and switch"). These alternative ideas are currently reflected in two seemingly opposing theories of anterior cingulate cortex function, namely the conflict monitoring versus the outcome evaluation account. Botvinick (2007) recently suggested that both positions might converge on the detection of aversive signals. Here, we will show that low perceptual fluency, which is known to evoke negative affective reactions, triggers the mobilization of cognitive effort even in the absence of response conflicts. More precisely, in three experiments effort adjustments in reaction to fluency manipulations as indicated by significant interactions of Fluency( N ) × Fluency(N-1) were found. It follows that an aversive signal (here: low fluency) is not only used for effort prediction but also for effort adjustments.