Two experiments evaluated the hypothesis that perceptual fluency is used to infer prior occurrence. Subjects heard (Experiment 1) or saw (Experiment 2) a list of words and then were presented in the same modality with both these and other words twice in succession: first in a more or less impoverished fashion, and then in clear fashion. For the first of these two presentations, the subjects tried to identify the word; for the second, they gave a recognition judgement. As predicted by the perceptual fluency hypothesis, and as has been found in previous research, the recognition judgments were more positive for identified words than for unidentified words. However, degree of impoverishment, by which apparent perceptual fluency was brought under experimental control, did not affect the recognition judgments. The perceptual fluency hypothesis was therefore not supported, and the observed relation between identification and recognition was attributed to an item selection effect.

Cognitive psychology is finding increasing use for the word fragment completion test, in which words have to be completed from a subset of their letters (e.g., horizon from --r-z--). Researchers often try to restrict their fragments to those that can be completed with only one word, but this is difficult to do and probably never has been achieved. To help resolve this problem, a list is provided of 1,086 three-to eight-letter words, each of which is uniquely specified by a two-letter fragment, where uniqueness is defined on the basis of two sizable word collections.The word fragment completion test is playing an increasingly prominent role in experimental psychology. The test involves the completion of word fragments of the sort that occur in a partly solved crossword puzzle. For example, --r-z--might be given as a test item for the target word horizon.The increase in usage of this test is in part an expression of the general liberalization of research methodology that has come with the information processing revolution. A more particular cause is the keen interest that has recently sprung up in the facilitation of word perception that arises when the word is encountered beforehand.A prior encounter with a word has been found to enhance the facility with which it is read (Brooks, 1987; Johnston, Dark, & Jacoby, 1985;Kolers, 1976), the speed with which it is classified as a word rather than as a nonword (Carroll & Kirsner, 1982; Feustel, Shiffrin, & Salasoo, 1983), and the likelihood of its being identified from a tachistoscopic presentation (Jacoby, 1983; Jacoby & Dallas, 1981). These perceptual priming tests do not inquire whether the words were presented beforehand, and their results have shown perceptual priming even for words whose prior presentations are not recollected (Jacoby & Witherspoon, 1982; Tulving, Schacter, & Stark, 1982; Watkins & Gibson, in press). Although the word fragment procedure is sometimes (e.g., Horowitz, White, & Atwood, 1968;Nelson & McEvoy, 1979; Tulving & Watkins, 1973) used to cue recollection of prior occurrence ("complete the fragment with a word from the list just presented"), it is perhaps more often (e.g., Light, Singh, & Capps, 1986; Roediger & Blaxton, 1987; Tulving et al., 1982) used as another test of perceptual priming ("complete the fragment with a word").The word fragment completion test has the advantage over other perceptual priming tests of being easy to administer. Also, it is a simple matter to create an ordinal scale of fragment completion difficulty. Thus, for a given word length, a two-letter fragment (--r-z--) can be assumed to be more difficult to complete than a three-letter fragment (--r-zo-), which in tum can be assumed to be more difficult to complete than a four-letter fragment (-or-zo-), and so on. Although there are bound to be exceptions, such assumptions are likely to hold up in most cases, especially when the letters in the smaller fragments are retained as part of the larger fragments.The word fragment completiontest does, however, have a dis...

Comparative evaluation of population recovery capabilities of 35 cluster analysis methods defined by different combinations of 5 profile similarity measures and 7 agglomeration rules was undertaken using artificial data that represented duplicate mixture samples from 4 latent populations. The latent population mean profiles differed primarily in elevation or in 'pattern parameters. Latent population sampling variances were controlled to provide two different levels of realistic overlap. The within‐population distributions were multivariate normal with diagonal covariance structure. Across all conditions examined, complete linkage and Ward's minimum variance methods, used with Euclidian or city block interprofile distance measures, performed best. Single linkage, median, and centroid methods were substantially inferior for clustering individuals in accordance with true population memberships.

Heterogeneity of variance produces serious bias in conventional analysis of variance tests of significance when cell frequencies are unequal. Welch in 1938 and 1947 proposed an adjusted t test for the difference between two means when cell frequencies and population variances are both unequal. This article describes two ways to use the Welch t to evaluate the significance of the main effect for two treatments across k levels of a concomitant factor in a two-way design. Monte Carlo results document the bias in conventional analysis of variance tests and the stable and appropriately conservative results from applications of the Welch t to evaluation of treatment effects in the two-way design.

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The experiments reported here investigated whether changes of typography affected priming of word stem completion performance in older and younger adults. Across all experiments, the typeface in which a word appeared at presentation either did or did not match that of its 3-letter stem at test. In Experiment 1, no significant evidence of a typography effect was found when words were presented with a sentence judgment or letter judgment task. However, subsequent experiments revealed that, in both older and younger adults, only words presented with a syllable judgment task gave rise to the typography effect (Experiments 2-4). Specifically, performance was greater, when the presentation and test typeface matched than when they did not. Experiment 5, which used stem-cued recall, did not reveal a difference between syllable and letter judgment tasks. These findings highlight the complex nature of word stem completion performance.

This paper describes a series of experiments in which we demonstrated that "dysphonemic" word stems, which are likely not pronounced in isolation as they are within a word (e.g.,MUS in MUSHROOM or LEG in LEGEND), showed less priming than did "phonemic stems" (e.g., MUS in MUSTARD or LEG in LEGACY). Furthermore, words with either dysphonemic or phonemic three-letter stems gave rise to equivalent levels of priming when test cues were four-letter stems (LEGE) or word fragments (L_G_ND). Moreover, the difference between phonemic and dysphonemic stems persisted when nonpresented completion rates were matched. A [mal cued-recall experiment revealed that performance was greater for phonemic stems than for dysphonemic stems and that this difference was greater for older participants than for younger ones. These results are not readily accounted for by extant theoretical approaches and point to important methodological issues regarding stem completion.

An experiment is reported in which subjects first heard a list of words and then tried to identify these same words from degraded utterances. Paralleling previous findings in the visual modality, the probability of identifying a given utterance was reduced when the utterance was immediately preceded by other, more degraded, utterances of the same word. A second experiment replicated this "cue-depreciation effect" and in addition found the effect to be weakened, if not eliminated, when the target word was not included in the initial list or when the test was delayed by two days.