Attention and task difficulty: When is performance facilitated?

Under certain conditions, when initiating a trial is made difficult, task p erformance improves as the task becomes harder to do. This counterintuitive finding has led to a distinction between the motor difficulty and the cogn itive difficulty of a task. The present report summarizes three replication s of an experiment in which the two aspects of difficulty were manipulated orthogonally in a recognition task. Participants (total N = 67) responded s ignificantly 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 e xposure duration). Visual gaze and pupil dilation data supported the interp retation that attention is elicited by increases in motor difficulty and th at performance can benefit from this allocation of attention or mental effo rt. (C) 2001 Academic Press.