Spacing repetitions over 1 week.

Does varying the spacing of repetitions over intervals as long as I week affect recall? The answer from three experiments is yes. Subjects incidentally processed words repeated within a single list and words repeated in separate lists at list spacings of up to I week. Memory was tested by free recall shortly after the second presentations or after retention intervals of up to I week. Recall of the words repeated across separate lists conformed to a proportionality rule. When the retention interval is short relative to the spacing intervals, performance is inversely related to spacing. When the retention interval is a large proportion of the spacing intervals, performance is directly related to spacing. Does varying the spacing of repetitions within a single list affect recall after a retention interval of 2 weeks? The answer depends on the processing used while studying the words. Processing that generated interitem associations resulted in a within-list spacing effect even after a 2-week retention interval. Without the interitem associations, the effect was absent after a l-day retention interval. Most of these findings were explained by examining the changing relationship between the retrieval context and the context stored during study.