Biomedical subjects

Kenneth J Malmberg

Publications and source records attributed to Kenneth J Malmberg.

9 recordsLinked to original sources

PubMed2005

The "one-shot" hypothesis for context storage.

In 3 experiments motivated by the implicit memory literature, the authors investigated the effects of different strengthening operations on the list strength effect (LSE) for explicit free recall, an effect posited by R. M. Shiffrin, R. Ratcliff, and S. E. Clark (1990) to be due to context cuing. According to the one-shot hypothesis, a fixed amount of context is stored when an item is studied for at least 1 or 2 s. Beyond the initial context storage, increases in study time or different orienting tasks do not influence the amount of context that is stored, and thus only spaced repetitions should produce a positive LSE. Consistent with prior findings, spaced repetitions always produced a positive LSE, but increases in depth of processing, study time, and massed repetitions did not. A model implements the one-shot hypothesis, and a role for context storage as a link between episodic and semantic memory is discussed.

Cues↗

PubMed2004

High-level effects of masking on perceptual identification.

The extent to which visual form versus higher-level information is used to identify briefly flashed words is assessed in a perceptual identification task. In this task, a word is briefly flashed, post-masked, and a decision is made between two alternatives. The availability of visual (e.g., case or color) and higher-level information (e.g., abstract letter codes, phonology, and meaning) was manipulated by varying the information that discriminates the alternatives. Performance was better with higher-level than with visual information when pattern post-masks were used, but the reverse occurred without masking. The authors conclude that both higher-level and visual-form information can be used to identify words with the strategy depending on the information available at the time of the choice.

Cognition↗

PubMed2004

Modeling the effects of repetitions, similarity, and normative word frequency on old-new recognition and judgments of frequency.

Judgments of frequency for targets (old items) and foils (similar; dissimilar) steadily increase as the number of times a target is studied increases, but discrimination of targets from similar foils does not steadily improve, a phenomenon termed registration without learning (D. L. Hintzman & T. Curran, 1995; D. L. Hintzman, T. Curran, & B. Oppy, 1992). The present experiment explores this phenomenon with words of differing normative word frequency. The retrieving-effectively-from-memory model (REM; R. M. Shifrrin & M. Steyvers, 1997, 1998) predicts that low-frequency words will be better recognized than high-frequency words because low-frequency words have more distinctive memory representations. A corollary of this assumption predicts that the typical recognition word-frequency effect will be disrupted when similar foils are tested. These predictions were confirmed, but to fit both the recognition and the judgment-of-frequency data, the authors used a "dual-process" extension of the REM model.

Attention↗

PubMed2004

Turning up the noise or turning down the volume? On the nature of the impairment of episodic recognition memory by midazolam.

E. Hirshman, J. Fisher, T. Henthom, J. Amdt, and A. Passanname (2002) found that Midazolam disrupts the mirror-patterned word-frequency effect for recognition memory by reversing the typical hit-rate advantage for low-frequency words. They noted that this result is consistent with dual-process accounts (e.g., R. C. Atkinson & J. F. Juola, 1974; G. Mandler, 1980; A. P. Yonelinas, 1994) of the word frequency effect for recognition memory (S. Joordens & W. E. Hockley. 2000; L. M. Reder et al. 2000). The present authors show that this finding is also consistent with a variety of single-process, retrieving effectively- from-memory (REM) models (R. M. Shiffrin & M. Steyvers, 1997), the simplest of which assumes that Midazolam decreases the accuracy with which memory traces are stored. These findings therefore do not discriminate between single- and dual-process models of recognition memory.

Attention↗

PubMed2003

The effect of normative context variability on recognition memory.

According to some theories of recognition memory (e.g., S. Dennis & M. S. Humphreys, 2001), the number of different contexts in which words appear determines how memorable individual occurrences of words will be: A word that occurs in a small number of different contexts should be better recognized than a word that appears in a larger number of different contexts. To empirically test this prediction, a normative measure is developed, referred to here as context variability, that estimates the number of different contexts in which words appear in everyday life. These findings confirm the prediction that words low in context variability are better recognized (on average) than words that are high in context variability.

Attention↗

PubMed2003

The word frequency effect for recognition memory and the elevated-attention hypothesis.

Empirical tests were conducted on the elevated-attention hypothesis that low-frequency (LF) words are better recognized than high-frequency (HF) words because LF words attract more attention than do HF words (e.g., Glanzer & Adams, 1990). The elevated-attention hypothesis predicts that the hit rate advantage for LF words should be reduced by increases in attentional strain at study. We first tested this prediction in two experiments by varying the amount of experimenter-controlled study time (on the basis of the assumption that a decrease in study time would reduce the amount of resources available for studying a word). The elevated-attention hypothesis was confirmed, but only when words were studied for relatively short durations. This finding led us to formulate an early-phase elevated-attention hypothesis that proposes that more attentional resources are allocated to LF words than to HF words only during the early phase of encoding (which produces the LF hit rate advantage in subsequent recognition) and that the allocation of attentional resources during the late phase of encoding is not greater for LF words than for HF words. An additional empirical test of this revised hypothesis was conducted: Experimenter-controlled study time and the composition of the to-be-remembered pairs of words were varied orthogonally. The results confirmed the early-phase elevated-attention hypothesis.

Attention↗

PubMed2002

List composition and the word-frequency effect for recognition memory.

The attention/likelihood theory (ALT; M. Glanzer & J. K. Adams, 1990) and the retrieving effectively from memory (REM) theory (R. M. Shiffrin & M. Steyvers, 1997) make different predictions concerning the effect of list composition on word recognition. The predictions were empirically tested for two-alternative forced-choice, yes-no, and ratings recognition tasks. In the current article, the authors found that discrimination of low-frequency words increased as the proportion of high-frequency words studied increased. The results disconfirm the ALT prediction that recognition is insensitive to list composition, and they disconfirm the predictions of the REM model described by R. M. Shiffrin and M. Steyvers (1997). The current authors discuss a slightly modified version of REM that can better predict our findings, and we discuss the challenges the present findings pose for ALT and REM.

Attention↗

PubMed2002

Feature frequency effects in recognition memory.

Rare words are usually better recognized than common words, a finding in recognition memory known as the word-frequency effect. Some theories predict the word-frequency effect because they assume that rare words consist of more distinctive features than do common words (e.g., Shiffrin & Steyvers's, 1997, REM theory). In this study, recognition memory was tested for words that vary in the commonness of their orthographic features, and we found that recognition was best for words made up of primarily rare letters. In addition, a mirror effect was observed: Words with rare letters had a higher hit rate and a lower false-alarm rate than did words with common letters. We also found that normative word frequency affects recognition independently of letter frequency. Therefore, the distinctiveness of a word's orthographic features is one, but not the only, factor necessary to explain the word-frequency effect.

Humans↗

PubMed2002

On the form of ROCs constructed from confidence ratings.

A classical question for memory researchers is whether memories vary in an all-or-nothing, discrete manner (e.g., stored vs. not stored, recalled vs. not recalled), or whether they vary along a continuous dimension (e.g., strength, similarity, or familiarity). For yes-no classification tasks, continuous- and discrete-state models predict nonlinear and linear receiver operating characteristics (ROCs), respectively (D. M. Green & J. A. Swets, 1966; N. A. Macmillan & C. D. Creelman, 1991). Recently, several authors have assumed that these predictions are generalizable to confidence ratings tasks (J. Qin, C. L. Raye, M. K. Johnson, & K. J. Mitchell, 2001; S. D. Slotnick, S. A. Klein, C. S. Dodson, & A. P. Shimamura, 2000, and A. P. Yonelinas, 1999). This assumption is shown to be unwarranted by showing that discrete-state ratings models predict both linear and nonlinear ROCs. The critical factor determining the form of the discrete-state ROC is the response strategy adopted by the classifier.

Humans↗