Interactions Between Study Task, Study Time, and the Low-Frequency Hit Rate Advantage in Recognition Memory.

In studies of episodic recognition memory, low-frequency words (LF) have higher hit rates (HR) and lower false alarm rates (FAR) than do high-frequency words (HF), which is known as the mirror pattern. A few findings have suggested that requiring a task at study may reduce or eliminate the LF-HR advantage without altering the LF-FAR effect. Other studies have suggested that the size of the LF-HR advantage interacts with study time. To explore such findings more thoroughly and relate them to theory, the authors conducted 5 experiments, varying study time and study task. The full mirror pattern was found only in 2 cases: the standard condition requiring study for a later memory test and a condition requiring a judgment about unusual letters. The authors explain their findings in terms of the encoding of distinctive features and discuss the implications for current theories of recognition memory and the word frequency effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

List-strength effect: II. Theoretical mechanisms.

R. Ratcliff et al (see record 1990-13916-001) examined the list-strength effect: the effect of strengthening (or weakening) some list items upon memory for other list items. The list-strength effect was missing or negative in recognition, missing or positive in cued recall, and large and positive in free recall. We show that a large number of current models fail to predict these findings. A variant of the SAM model of G. Gillund and R. M. Shiffrin (see record 1984-08340-001), involving a differentiation hypothesis, can handle the data. A variant of MINERVA 2 (D. Hintzman [see PA, Vols 74:6242 and 76:10832] 1986, 1988) comes close but has some problems. Successful variants of a variety of composite and network models were not found (e.g., D. H. Ackley et al [see PA, Vol 73:7981]; J. A. Anderson, 1972 [see PA, Vol 51:10424]). The results suggest constraints on the future development of such models. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

List Discrimination in Associative Recognition and Implications for Representation.

Four experiments tested the predictions made by the model outlined in A. H. Criss and R. M. Shiffrin (2004b). Participants studied 2 successive lists of pairs followed by a recognition memory test for the most recent list. Some items and some pairs were repeated across the 2 lists. Critically, a given item could be repeated in the same or different type of pair. For associative recognition, performance was only affected by repetitions in the same pair type. However, in single-item recognition confusions occurred for both types of repetitions. The results are as predicted and confirm the assumption that different associative representations were stored even when the same token repeated in different pair types, whereas similar item representations were used regardless of pair type. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory codes and episodes in models of word identification: A reply to Johnston, van Santen, and Hale.

Proposes that the activation model of identification benefits for repeated words and pseudowords proposed by J. C. Johnston et al (see record 1986-11005-001) is a variant of the present authors' (see record 1986-03032-001) code/episode model, which was used to explain the temporary and long-lasting effects of repetitions. The X and Y factors of Johnston et al may reflect the operation of episodic memory traces and codification, respectively. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Bayesian model for implicit effects in perceptual identification.

Retrieving effectively from memory (REM; R. M. Shiffrin & M. Steyvers, 1997), an episodic model of memory, is extended to implicit memory phenomena, namely the perceptual identification studies reported in R. Ratcliff and G. McKoon (1997). In those studies, the influence of prior study was greatest when words were presented most briefly and when forced-choice targets and foils were most similar. R. Ratcliff and G. McKoon use these data to argue against models in which prior study changes a word's representation. A model in which prior study changes a word's representation by adding context information is fit to their data; at test, the model uses a Bayesian decision process to compare the perceptual and context features associated with the test flash to stored traces. The effects of prior study are due to matching extra context information and are larger when alternatives share many features, thereby reducing noise that attenuates these effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Building permanent memory codes: Codification and repetition effects in word identification.

Three experiments, with 46 university students, investigated the memory processes that underlie 2 phenomena in threshold identification: word superiority over pseudowords and the repetition effect (a prior presentation of an item facilitates later identification of that item). Codification (i.e., the development of a single memory code that can be triggered even by fragmented input information) explains the faster and more accurate identification of words than pseudowords. The present studies traced the development and retention of such codes for repeated pseudowords and examined the growth and loss of the repetition effect for both pseudowords and words. After approximately 5 prior occurrences, words and pseudowords were identified equally accurately in 2 types of threshold identification tasks, suggesting that codification had been completed for pseudowords. Although the initial word advantage disappeared, the accuracy of identification still increased with repetitions. The facilitation caused by repetition was not affected much by spacing within a session, but it dropped from day to day and disappeared after a delay of 1 yr. Results suggest an episodic basis for the repetition effect. After 1 yr, performance was equal for old pseudowords and new and old words: All these levels were superior to that for new pseudowords, suggesting that the learned codes for pseudowords are as strong and permanent as the codes for words. A model of identification is presented in which feedback from old codes and episodic images in memory facilitates better processing. (63 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrieval strategies in recall of natural categories and categorized lists.

Exps I and II, using a total of 192 undergraduates, examined the effect of retrieval strategies on 3 or 12 min of recall from a natural category. Exp III, with 29 undergraduate Ss, examined the effect of strategy on 6 min of recall from a subset of a category presented as a list. In Exps I and II, a large recall deficit was produced by retrieval strategies involving recall in alphabetic order and by size of the words' referents, relative to free recall. In Exp III, 4 strategies—alphabetic, size, serial order, and free recall—gave similar levels of recall after 6 min, though the growth rate of the cumulative output functions differed among the strategies. An extension of the search of associative memory model of J. G. Raaijmakers and R. M. Shiffrin (1980; see also PA, Vol 66:491) was developed to explain these results; the new model postulates attention sharing among probe cues and the use of idiosyncratic strategies for free recall from natural categories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Episodic and lexical contributions to the repetition effect in word identification.

Conducted 5 experiments (1 in 2 parts) with undergraduates (N?=?198) to study the repetition effect (RE); this term refers to the finding that the speed and accuracy of naming a visually presented word is enhanced by a single prior presentation of the word. Procedures are described in detail, and the findings of the experiments are compared and discussed. A model was developed that outlines the relative contributions to the RE in word and nonword identification that are made (a) by episodic traces for particular events and (b) by unitized representations of words in semantic memory. A prominent role in the model is played by the unitization that characterizes identification of words and is missing for nonwords. (51 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A retrieval model for both recognition and recall.

Extended the search of associative memory model for recall proposed by J. G. Raaijmakers and R. M. Shiffrin (see record 1981-20491-001) by assuming that a familiarity process is used for recognition. The recall model posits cue-dependent probabilistic sampling and recovery from an associative network. The present recognition model is closely related to the recall model because the total episodic activation due to the context and item cues is used in recall as a basis for sampling and in recognition to make a decision. The model, formalized in a computer simulation program, correctly predicts a number of findings in the literature as well as the results from an experiment on the word-frequency effect in which 80 undergraduates participated. (3? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

List-strength effect: I. Data and discussion.

Extra items added to a list cause memory for the other items to decrease (the list-length effect). In one of the present studies we show that strengthening (or weakening) some items on a list harms (or helps) free recall of the remaining list items. This is termed the list-strength effect. However, in seven recognition studies the list-strength effect was either absent or negative. This held whether strengthening was accomplished by extra study time or extra repetitions. The seven studies used various means to control rehearsal strategies, thereby providing evidence against the possibility that the findings were due to redistribution of rehearsal or effort from stronger to weaker items with a list. Current models appear unable to predict these results. We suggest that different retrieval operations underlie recall and recognition, as in the SAM model of G. Gillund and R. M. Shiffrin (see record 1984-08340-001), which can be made to fit the results with certain relatively minor modifications. (PsycINFO Database Record (c) 2010 APA, all rights reserved)