Studies of distributed practice. X. The influence of intralist similarity on learning and retention of serial adjective lists.

^*3^The major purpo»e of this study was nft discover the influence of intraliit similarity and intertrial interval on retention of serial adjectives. With regard to retention as a function of intralist similarity, several studies (4, 6, 7, 8) indicate that while intralist similarity may influence rate of learning, it has no influence on recall taken 24 hr. following learning. As yet, however, no tests of retention have been made for serial adjectives of varying levels ot intralist similarity. The data are conflicting concerning retention of rote-learned materials following acquisition with varying intertrial intervals. With serially learned nonsense syllables, Hovland (3) found better retention after spaced practice than after massed practice. We have found quite the opposite with comparable materials (6). Retention of paired adjectives may (4) or may not (8) be enhanced by distributed practice depending, we believe, upon degree of learning before the retention interval. Although degree of learning has r>at clearly been shown to be the critical variable, some evidence (summarized in 8) suggests that with high degrees of learning massed practice gives better recall, and with low degrees of learning spaced practice gives better recall. In any event, data available at the present time do not