Interleaved practice
Interleaved practice is described as continuously alternating between topics during practice[1]. Practising tasks in an interleaved order generally induces superior learning compared with practising in a repetitive order, a phenomenon known as the contextual-interference effect[2].
Key points
- Compared with blocked practice, interleaved practice of different tasks is described as leading to superior long-term retention despite poorer initial acquisition performance[3].
- In undergraduate physics, replacing conventionally arranged homework with interleaved homework is described as able to foster longer lasting and more generalizable learning[1].
- In a study of surgical residents, interleaved practice appeared to have advantages over blocked practice in developing and retaining skills[4].
An undergraduate physics course
Over 8 weeks, students in two lecture sections of a university-level introductory physics course completed thrice-weekly homework assignments[1]. The problems were either interleaved, meaning alternating topics, or conventionally arranged, meaning one topic practised at a time[1]. Two surprise tests then contained novel and more challenging problems[1].
After interleaved practice, students recalled more relevant information and more frequently produced correct solutions[1]. Observed median improvements were 50% on test 1 and 125% on test 2[1].
Surgical skills training
In surgical training, the recommended practice for learning Fundamentals of Laparoscopic Surgery tasks is to practise them one at a time until proficient, which is called blocked practice[4]. Interleaved practice is described there as rotating the tasks rather than learning them one at a time[4].
Residents were randomised into a blocked group or an interleaved group and compared over 20 trials of each of four tasks[4]. Four weeks later, participants returned and completed two additional trials of each task[4]. The interleaved group showed significantly better performance on the peg transfer task[4].
Motor sequences and the brain
In a serial reaction time task, participants who reported no awareness of the sequences still showed a benefit of interleaving for both retention and transfer, compared with blocked practice[3]. Those who trained with blocked sequences were left unprepared for interleaved sequences at test, while those who trained with interleaved sequences were unaffected by testing condition[3]. Learning resulting from blocked practice is therefore described as possibly less flexible and more vulnerable to testing conditions[3].
In another study, sixteen adults practised sequences in a repetitive order and, 2–4 weeks later, in an interleaved order, or the other way round[2]. On Day 2 of practice, functional connectivity between brain regions was greater in the interleaved condition than in the repetitive one[2]. The increased connectivity between the seeded regions and sensorimotor cortical areas correlated with the benefit of interleaved practice during later retention[2]. These data are described as suggesting that interleaved practice benefits learning by enhancing coordination of sensorimotor cortical regions[2].
Limits and perceptions
Despite benefiting more from interleaved practice, students in the physics study tended to rate the technique as more difficult and incorrectly believed that they learned less from it[1].
In the surgical study, trends favouring the interleaved group resulted for the other tasks[4]. Standardised mean differences in favour of the interleaved group were substantial both at the end of practice and at follow-up, with the exception of the pattern cut[4]. The authors encourage others to experiment with the method to confirm their findings[4].
Sources
- B Samani J, Pan SC. Interleaved practice enhances memory and problem-solving ability in undergraduate physics. NPJ Sci Learn. 2021. doi:10.1038/s41539-021-00110-x
- B Lin CH, Chiang MC, Knowlton BJ, Iacoboni M, Udompholkul P, Wu AD. Interleaved practice enhances skill learning and the functional connectivity of fronto-parietal networks. Hum Brain Mapp. 2013. doi:10.1002/hbm.22009
- B Schorn JM, Knowlton BJ. Interleaved practice benefits implicit sequence learning and transfer. Mem Cognit. 2021. doi:10.3758/s13421-021-01168-z
- B Goldin SB, Horn GT, Schnaus MJ, Grichanik M, Ducey AJ, Nofsinger C, et al.. FLS skill acquisition: a comparison of blocked vs interleaved practice. J Surg Educ. 2014. doi:10.1016/j.jsurg.2014.01.001