Effect of uniform versus expanding retrieval practice on the recall of physiology information

The purpose of this study was to compare the retention of selected physiology concepts throughout 30 days of two different uniform schedules of retrieval and two different expanding schedules of retrieval. Participants (n = 250) first read and reread 30 immunology and reproductive physiology concepts and were then repeatedly assessed, without feedback, according to one of the following four randomly assigned schedules: 1) immediately after learning and again 9 and 19 days later [uniform (days 1, 10, and 20)]; 2) 7, 14, and 21 days after learning [uniform (days 8, 15, and 22)]; 3) immediately after learning and again 5 and 15 days later [expanding (days 1, 6, and 16)]; and 4) 1, 6, and 16 days after learning [expanding (days 2, 7, and 17)]. All participants completed a final assessment 29 days after learning the physiology concepts. Mean final assessment scores ± SE for the uniform (days 1, 10, and 20), uniform (days 8, 15, and 22), expanding (days 1, 6, and 16), and expanding (days 2, 7, and 17) groups were 36.15 ± 1.97, 32.31 ± 1.87, 45.80 ± 2.56, and 39.71 ± 2.48, respectively. There were no differences in final assessment scores between the two expanding retrieval groups, but expanding (days 1, 6, and 16) group scores were significantly higher than those in both uniform retrieval groups (ANOVA, F = 6.52, P = 0.00). Also, the combined mean of the two expanding retrieval conditions (42.57 ± 1.80) was significantly higher (F = 14.09, P = 0.00) than the combined mean of the two uniform retrieval conditions (34.10 ± 1.36). The results indicate that participants benefited more from expanding retrieval practice, particularly when the first assessment was administered immediately after learning.