A primary reason that memory researchers are interested in word frequency is that it produces opposite effects on recognition and recall. Low-frequency words produce better recognition memory, whereas high-frequency words produce superior recall (at least in pure-list designs, as discussed below) (see, e.g., Shepard, 1967; and see Gregg, 1976, for an early review). These results have informed debates about the relationship between recall and recognition, and they are traditionally interpreted as strong evidence against single-process models of recognition and recall (e.g., Crowder, 1976;Murdock, 1974). Word frequency effects are also important to theoretical models of recognition memory, such as dual-process models (e.g., Chalmers & Humphreys, 1998;Gardiner & Java, 1990;Guttentag & Carroll, 1997;Jacoby & Dallas, 1981;Mandler, 1980), as well as to attempts to delineate empirical regularities in recognition memory, such as the mirror effect (e.g., Glanzer, Adams, Iverson, & Kim, 1993;Greene, 1996;Maddox & Estes, 1997;Wixted, 1992).A traditional account of the word frequency effect in recall is that high-frequency words lend themselves to more organizationaland interitem associative processing (Gregg, 1976;Schulman, 1976;Zechmeister & Nyberg, 1982), types of encoding that are especially useful in recall but that have little impact on recognition (e.g., Hunt & McDaniel, 1993;Kintsch, 1977). Several results are consistent with this view. First, in comparison with low-frequency words, high-frequency words produce more category clustering in recall protocols (e.g., Bousfield & Cohen, 1955), a standard index of organizational processing at encoding (e.g., Hunt & Einstein, 1981). Second, meaning-based associations are more easily produced in lists of high-frequency items (e.g., Sumby, 1963;Tulving & Patkau, 1962), enhancing later recall. Third, the index of interitem associative strengths, which is predictive of recall, is greater with high-than with low-frequency lists (Deese, 1960) (see Gregg, 1976, for additional evidence for the importance of organizational and associative bases of the word frequency effect in recall). Finally, and most important for the present purposes, high-frequency words produce greater order memory, as measured by the order reconstruction task (DeLosh & McDaniel, 1996). Under the standard assumption that this and other tests of absolute order are based on interitem associations (Greene, Thapar, & Westerman, 1998; Hunt & McDaniel,1993;McDaniel, DeLosh, & Merritt, 2000; see also Li & Lewandowsky, 1993), these results imply that high-frequency words lead to more interitem associative encoding than do low-frequency words.This traditional view is expanded in the order-encoding hypothesis proposed by DeLosh and McDaniel (1996). This hypothesis proposes that word frequency produces an encoding tradeoff between information about the item itself and information about the order in which items occur. According to this view, the unusual nature of low-frequency words focuses processing resources on item ch...