Specific Versus Varied Practice in Perceptual Expertise Training

We used a longitudinal randomized 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 10 hours over 2 to 4 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 6 to 8 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 a single category (versus many) instills better near transfer, but category-specific and category-general visual search training appear equally effective for developing task-general expertise. Public Significance Statement The findings in this study suggest that training to find features for 10 hours-in a variety of images including fingerprints, aerial photographs, bark images, bone cancer images, retinas, and footwear impressions-can lead to robust and generalizable perceptual skill with fingerprints. This study also adds to previous work in demonstrating that practice with images from one category (fingerprints in this case) is more effective for improving performance on a trained task with the trained image category than practice with a wide breadth of image categories. Moreover, training across a wide variety of categories (rather than one) does not result in better performance with novel categories in the short term, but it may lead to more generalizable skill in the long term.