Specific Versus Varied Practice in Perceptual Expertise Training

We used a longitudinal randomised control experiment to compare the effect of specific practice (training on one form of a task) and varied practice (training on various forms of a task) on perceptual learning and transfer. Participants practiced a visual search task for ten hours over two- to four-weeks. The specific practice group searched for features only in fingerprints during each session whereas the varied practice group searched for features in five different image categories. Both groups were tested on a series of tasks at four time points: before training, midway through training, immediately after training ended, and six- to eight-weeks later. The specific group improved more during training and demonstrated greater pre-post performance gains than the varied group on a visual search task with untrained fingerprint images. Both groups improved equally on a visual search task with an untrained image category, but only the specific group’s performance dropped significantly when tested several weeks later. Finally, both groups improved equally on a series of untrained fingerprint tasks. Practice with respect to single category (versus many) instils better near transfer, but category-specific and category-general visual search training appear equally effective for developing task-general expertise.