Mobilizing cognition for speeded action: try-harder instructions promote motivated readiness in the constant-foreperiod paradigm.

We examined the effect of motivational readiness on cognitive performance. An important but still not sufficiently elaborated question is whether individuals can voluntarily increase cognitive efficiency for an impending target event, given sufficient preparation time. Within the framework of the constant-foreperiod design (comparing reaction time performance in blocks of short and long foreperiod intervals, FPs), we examined the effect of an instruction to try harder (instructional cue: standard vs. effort) in a choice-reaction task on performance speed and variability. Proceeding from previous theoretical considerations, we expected the instruction to speed-up processing irrespective of FP length, while error rate should be increased in the short-FP but decreased in the long-FP condition. Overall, the results confirmed this prediction. Importantly, the distributional (ex-Gaussian and delta plot) analysis revealed that the instruction to try harder decreased distributional skewness (i.e., longer percentiles were more affected), indicating that mobilization ensured temporal performance stability (persistence).