A survey of studies in which the effect of natural language word frequency on free recall has been examined reveals an interesting paradox. When one compares free recall performance for pure lists of high-frequency (HF) words (e.g., letter, money, and people) with that for pure lists of low-frequency (LF) words (e.g., comet, diaper, and syringe), there is typically an advantage for HF items (Deese, 1960;DeLosh & McDaniel, 1996;Duncan, 1974;Gregg, 1976;Gregg, Montgomery, & Castaño, 1980;J. F. Hall, 1954;May & Tryk, 1970;Postman, 1970;Sumby, 1963). When lists comprising both HF and LF words are given, however, the HF advantage is eliminated, and a free recall advantage for LF items is often observed (DeLosh & McDaniel, 1996;Duncan, 1974;Gregg, 1976;Gregg et al., 1980;May & Tryk, 1970; for an exception, see Balota & Neely, 1980). This reversal as a function of list composition appears to be a robust phenomenon and, as such, represents an important theoretical challenge for explanations of the effect of word frequency on free recall.In developing theoretical accounts of word frequency effects, it is noteworthy that the pattern described above fits within a larger pattern of results in which the effect of a stimulus variable on free recall is reversed or eliminated as a function of list composition. List composition effects include better recall of generated words than of read words in mixed, but not pure, lists (e.g., Mulligan, 2002;Serra & Nairne, 1993;Slamecka & Katsaiti, 1987), better recall of perceptually degraded words than of intact words in mixed, but not unmixed, lists (Mulligan, 1999), better recall of bizarre sentences than of common sentences in mixed, but not pure, lists (e.g., McDaniel & Einstein, 1986;McDaniel, Einstein, DeLosh, May, & Brady, 1995;McDaniel, DeLosh, & Merritt, 2000), better recall of humorous sentences than of common sentences in mixed, but not unmixed, lists (Schmidt, 1994), and better recall of orthographically distinct words than of orthographically common words in mixed, but not pure, lists (Hunt & Elliot, 1980 The order-encoding view of the word frequency effect proposes that low-frequency (LF) items attract more attention to the encoding of individual-item information than do high-frequency (HF) items, but at the expense of order encoding (DeLosh & McDaniel, 1996). When combined with the assumption that free recall of unrelated words is organized according to their original order of presentation, this view explains the finding that HF words are better recalled than LF words in pure lists but that, in mixed lists, recall is better for LF words. The present study confirmed that in mixed lists, order memory becomes equivalent for HF and LF words and that the predicted pattern of order memory and recall holds for incidental order-encoding conditions, for longer lists than those used in previous experiments, and for lists with minimal interitem associativity. Moreover, recall from HF lists declined, but recall from LF lists improved, in related-word lists, relative to unrelated-word ...