MEMORY FOR THE SPACING OF REPETITIONS

Memory for the spacing of two events was investigated in an "incidental learning" situation. When the events were two instances of the same word, judged spacing increased monotonically with actual spacing; when the events were single occurrences of two different words, judged spacing was not significantly affected by actual spacing. It is suggested that the spacing of repetitions is encoded in memory as an implicit judgment of recency, stored at the time of the second occurrence of the word, and retrieved on the spacing-judgment test. A number of recent studies have shown that when 5s study word lists, information about temporal variables is stored in memory. Even under incidental learning conditions, for example, the recency or serial position of a single occurrence of a word can be recalled with some accuracy (Hintzman, Block, & Summers, 1973; Zimmerman & Underwood, 1968), the serial position of several repetitions of the same word can be simultaneousl y remembered (Hintzman & Block, 1971), and a word's exposure duration can be judged to some extent independently of its frequency (Hintzman, 1970). These findings raise a general question about the extent to which memory is "time encoding": What other temporal variables are 5s able to recall ? Our present concern is with memory for