Attention and Task Difficulty: When Is Performance Facilitated?

Under certain conditions, when initiating a trial is made difficult, task performance improves as the task becomes harder to do. This counterintuitive finding has led to a distinction between the motor difficulty and the cognitive difficulty of a task. The present report summarizes three replications of an experiment in which the two aspects of difficulty were manipulated orthogonally in a recognition task. Participants (total N = 67) responded significantly more accurately and rapidly under conditions in which a cursor had to be moved very precisely (versus imprecisely) into a circle fixed in the center of a computer screen. However, accuracy and response time were compromised with increases in the cognitive difficulty variable (stimulus exposure duration). Visual gaze and pupil dilation data supported the interpretation that attention is elicited by increases in motor difficulty and that performance can benefit from this allocation of attention or mental effort.