Document Type



A stimulus movement effect has been reported in which learning by nonhuman animals was significantly better with moving than with stationary stimuli. In the present investigation, this effect was extended to human participants (N = 56) and further explicated. In Experiment 1 the students responded significantly more accurately and rapidly on a battery of computerized tasks with moving versus stationary stimuli. In Experiment 2 performance on a concurrent task was systematically slowed even as performance was enhanced on two different primary tasks by stimulus movement, which supports the interpretation that these effects are mediated by attention. A distinction between procedural and performance difficulty was made, in which increasing the former (e.g., with moving stimuli) appears to enhance concentration and improve performance, whereas performance difficulty makes a task harder to do correctly and impairs performance. Experiment 3 was a replication of Experiment 2 with rhesus monkeys in which essentially the same procedural difficulty effects were found. This series of experiments demonstrates for the first time stimulus movement effects in human learning, and it is the first study of which we are aware to examine the intensity of attention in nonhuman primates using dual-task methodology.