Contextual Interference Effect

The contextual interference effect is a finding in motor skill learning research in which practicing several different skills, or several variations of the same skill, in an interleaved and unpredictable order produces noticeably worse performance during the practice sessions themselves, yet leads to better retention and better transfer to new situations when skill is tested some time later, compared with practicing the same total amount using a blocked schedule that repeats one skill fully before moving to the next, which produces smoother, better-looking performance during practice itself but poorer long-term retention. The psychologists John Shea and Robyn Morris first demonstrated the effect experimentally in a widely cited 1979 study using a laboratory motor task, and it has since been replicated across a range of motor and even some verbal learning tasks. The effect is theoretically important, particularly within sport and motor-learning research, because it shows that how easy or difficult a practice method feels, and how good performance looks during that practice itself, is not a reliable guide to how effectively that method will actually promote lasting learning, with the more effortful, seemingly less efficient random practice schedule in fact producing the more durable, better transferring skill in the end. This counterintuitive relationship between short-term practice difficulty and long-term learning has made the contextual interference effect an influential example within the broader concept of desirable difficulties in skill acquisition, documented separately in this section for its role in verbal learning.