The effect of selected “desirable difficulty” learning strategies on retention of physiology information

The purpose of this study was to examine the effects of interleaving and expanding schedules of information retrieval on the retention of physiology concepts. Participants (n = 189) read dozens of passages that described immunology and reproductive physiology concepts. Approximately half of the participants read them in a blocked manner (e.g., aabbcc) and the other half in an interleaved manner (e.g., abcbca). Participants were then repeatedly assessed, without feedback, after either a uniform or an expanding series of intervals. Approximately half of the students from both the blocked and interleaved groups completed the assessments 1, 2 and 3 days after reading the passages (uniform schedule), whereas the other half completed the assessments immediately, 1 and 3 days after reading the passages (expanding schedule). One week after the 3rd assessment, all participants completed a final assessment. There were no significant differences in the assessment scores between the blocked and interleaved conditions, but those that followed the expanding schedule scored significantly higher on all four assessments than those that followed the uniform schedule. On the final assessment, the mean scores were 47.58±19.81 and 40.11±17.12 for the expanding and uniform schedules, respectively (F = 7.25, P < 0.00). The results indicate that the participants benefited more from an expanding schedule of retrieval practice.