Speed and Accuracy: A Complex Interplay in Skill Development

Theories and models of skill development often assume that speed and accuracy are interchangeable performance indices that improve in a straightforward relationship with extended practice. This ignores the fact that practice may alter the compromises between speed-accuracy tradeoff (SAT) which is known to set limits to performance. Thirty participants were trained on a simple psychomotor task. Practice significantly improved all speed measures but did not significantly reduce error rate. Specifically, the majority of errors occurred on trials with low target probability and did not decrease with increased practice. Moreover, the study found no relationship between speed and accuracy for trials with high target probability, but a clear tradeoff was found for trials with low target probability. The results highlight the complexity of the skill development process and demonstrate a situation where practice did not result in error reduction due to the complex interplay between SAT and target probability.