Abstract
After committing an error, people may slow down to avoid committing a subsequent error. This post-error adjustment, referred to as post-error slowing (PES), may be indicative of adaptive compensation geared towards improving performance, and as such, is sometimes coupled with post-error improvement in accuracy (PIA). However, the co-occurrence of these two phenomena has been inconsistent, leaving open questions whether PES serves a functional purpose. Here, we first reanalyzed data from a previous flanker study (N = 40) to investigate whether post-error adjustments co-occur with improvements in performance (functional) or not (non-functional) by comparing RT and accuracy between post-correct and post-error trials. Furthermore, by using a flanker task with absent, congruent, or incongruent distractors, we can explore whether cognitive demand differences yield different effects on PES and PIA. After excluding poor performers, we observed a significant PIA effect, suggesting that functional adjustments were applied uniformly across task conditions. However, this was not accompanied by PES, as expected, but instead, a marginally significant post-error speeding. This result provides evidence that PES and PIA are distinct phenomena. However, an alternative possibility is that a lengthy cue period and intertrial interval obscured our ability to observe PES. We therefore conducted a new, second experiment with both durations reduced to increase time pressure and thus the likelihood of observing slowing after an error. Nonetheless, preliminary data (N = 16) produced a similar post-error speeding as we observed in Experiment 1, with an additional interaction between post-response condition and flanker condition: post-error speeding was restricted to absent- and compatible-distractor trials and undetected for incongruent-distractor trials. In sum, these data suggest that participants may monitor errors to make broad, functionally appropriate adjustments on the subsequent trial, that do not consistently necessitate slowing.