Kenneth J. Malmberg, PhD

Department of Psychology

University of South Florida

Lehman, M. & Malmberg, K. J. (in press, .pdf). A global theory of remembering and forgetting from multiple lists. Journal of Experimental Psychology: Learning, Memory, & Cognition .

Forgetting is frustrating, usually because it is unintended. Other times, one may purposely attempt to forget an event. A global theory of recognition and free recall is presented that explains both types of forgetting and remembering from multiple list experiments. The critical assumption of the model is that both intentional and unintentional forgetting are often due to contextual interference. Unintentional forgetting is the natural result of contextual changes between study and test. Intentional forgetting is accomplished by a rapid, metacognitively instigated, change in mental context that renders to-be-forgotten information relatively inaccessible and to-be-remembered information more accessible (Sahakyan & Kelley, 2002). This occurs for both recognition and free recall. Implications for item-method directed forgetting, exclusion recognition, source memory, and encoding operations are discussed.

Criss, A. H. & Malmberg, K. J. (2008, .pdf). Evidence in favor of the early-phase elevated-attention hypothesis: The effects of object frequency and letter frequency, Journal of Memory and Language, 59, 331-345 .

One of the most studied and least well understood phenomena in episodic memory is the word frequency effect (WFE). The WFE is expressed as a mirror pattern where uncommon low frequency words (LF) are better recognized than common high frequency words (HF) by way of a higher HR and lower FAR. One explanation for the HR difference is the early-phase elevated-attention hypothesis which proposes two stages of encoding. In the first, called the early-phase, words are identified based on orthographic and/or phonological characteristics. LF words are composed of atypical features making their identification more difficult than HF words. This relative difficulty
during the early-phase results in the LF HR advantage. The first two experiments test the proposal that LF words are better recognized due to their distinct lexical features. The second stage of encoding, called the late phase, consists of controlled processing where the semantic features of the item are paramount. According to the early-phase elevated-attention hypothesis, semantic features of HF and LF words do not differ in diagnosticity and do not contribute to the word frequency effect. We find evidence for this assumption in the final experiment by comparing memory for words and objects.

Malmberg, K. J. (2008a, .pdf). Recognition Memory: A Review of the Critical Findings and an Integrated Theory for Relating Them. Cognitive Psychology , 57, 335-384.  

The development of formal models has aided theoretical progress in recognition memory research.
Here, I review the findings that are critical for testing them, including behavioral and brain imaging
results of single-item recognition, plurality discrimination, and associative recognition experiments
under a variety of testing conditions. I also review the major approaches to measurement and process
modeling of recognition. The review indicates that several extant dual-process measures of recollection are unreliable, and thus they are unsuitable as a basis for forming strong conclusions. At the process level, however, the retrieval dynamics of recognition memory and the effect of strengthening operations suggest that a recall-to-reject process plays an important role in plurality discrimination and associative recognition, but not necessarily in single-item recognition. A new theoretical framework proposes that the contribution of recollection to recognition depends on whether the retrieval of episodic details improves accuracy, and it organizes the models around the construct of efficiency. Accordingly, subjects adopt strategies that they believe will produce a desired level of accuracy in the shortest amount of time. Several models derived from this framework are shown to account the accuracy, latency, and confidence with which the various recognition tasks are performed.

Malmberg, K. J. (2008b). Towards an understanding of individual differences in episodic memory: Modeling the dynamics of recognition memory. in A. Benjamin and B. Ross (Eds.) The Psychology of Learning and Motivation: Skill and Strategy in Memory Use, Vol. 48, 313-349. (.pdf)

Malmberg, K. J. (2008). Investigating metacognitive control in a global memory framework, in J. Dunlosky and R. E. Bjork (Eds.) Handbook of Memory and Metacognition. (.pdf)

How does one learn? How does one remember? These are the broad questions that the Nelson and Narens (1990) research program addressed. Of course, they were not the first to ask these questions, but they did approach these questions in a novel way. The Nelson and Narens approach to understanding learning and memory can be viewed as an extension of Atkinson and Shiffrin’s (1968) proposal that memory consists of a set of memory structures and control processes. The memory structures are assumed to be used to support the performance of all learning and memory tasks, whereas control processes (e.g., rehearsal) are assumed to be strategically used to perform particular tasks. Many researchers have sought to understand the nature of the structural aspects of learning memory, and this has led to several formal models. Nelson and Narens, on the other hand, organized the prevalent measures and developed a framework that describes how the structural aspects of memory are monitored and controlled. It is a testament to the empirical richness of the Nelson and Narens metamemory framework that those modern researchers who investigate metamemory do so largely independently of those who investigate the structural aspects of memory (and vice versa). In this chapter, I consider how these two approaches to understanding learning and memory might be jointly used to build better models of learning and memory.

Malmberg, K. J. & Xu, J. (2007). On the flexibility and on the fallibility of associative memory, Memory & Cognition, 35(3), 545-556. (.pdf)

The authors report the results of four experiments that explored the flexibility and fallibility of associative recognition memory. In each experiment, pairs were studied one or more times, and the task was to discriminate intact from rearranged pairs. The critical findings are that the pattern of false-alarm rates were dependent on the nature of the recognition procedure (e.g., ratings versus yes-no) and the situation in which the task was performed. The specific pattern of findings suggest that subjects adopt different recognition strategies in order to achieve a desired level of performance in the most efficient manner possible by varying the degree to which they base their decisions on familiarity versus recollected information. Implications for theories of recognition memory are discussed.

Xu, J. & Malmberg, K. J.(2007). Moldeing the effects of verbal- and nonverbal-pair strength on associative recognition, Memory & Cognition, 35(3), 526-544 (.pdf)

Operations that improve the accuracy of associative recognition can do so in qualitatively different ways. Increasing repetitions and study time increases hit rates, but has small effects on false-alarm rates, and the specific patterns of false-alarms are dependent on the stimuli (e.g., pairs of words, pseudowords, faces, versus Chinese characters). In contrast, manipulating the type of stimuli that comprise pairs produces a robust mirror effect: The hit rate is greater and the false-alarm rate is lower for better recognized stimuli. To explain these findings, the authors extend a model of single-item recognition to associative recognition. Within this dual-process framework, the present results suggest that words are encoded more extensively than nonverbal stimuli and recognition of frequently encountered stimuli (words and faces) are more likely to be based on recollection than recognition of uncommon stimuli (pseudowords and Chinese characters).

Malmberg, K. J., Lehman, M., & Sahakyan, L. (2006, .pdf). On the Cost and Benefit of Taking it out of Context: Modeling the Inhibition Associated with Directed Forgetting, Proceedings of the 28th Meeting of the Cognitive Science Society, 549-554.

Forgetting can occur as the result of unconscious or automatic memory processes or as the result of conscious control. The later form of forgetting is often referred to as suppression, repression, or inhibition, and it is investigated in the laboratory using the directed forgetting procedure. The authors describe and empirically test the first formal model of directed forgetting, implemented within the framework of the Search of Association Memory Theory (SAM). The critical assumption is that episodic memory can be suppressed by a conscious attempt to alter the mental context in which new memories are encoded. The present model accounts for both veridical and erroneous free recall performance.

Malmberg, K.J. & Xu, J. (2006, .pdf). The Influence of Averaging and Noisy Decision Strategies on the Recognition Memory ROC, Psychonomic Bulletin & Review, 13 (1), 99-105.

Many single- and dual-process models of recognition memory predict that the ratings and remember– know receiver operating characteristics (ROCs) are the same, but Rotello, Macmillan, and Reeder (2004) reported that the slopes of the remember–know and ratings z-transformed ROCs (zROCs) are different. The authors show that averaging introduces nonlinearities to the form of the zROC and that ratings and remember–know zROCs are indistinguishable when constructed in a conventional manner. The authors show, further, that some nonoptimal decision strategies have a distinctive, nonlinear effect on the form of the single-process continuous-state zROC. The conclusion is that many factors having nothing to do with the nature of recognition memory can affect the shape of zROCs, and that therefore, the shape of the zROC does not, alone, characterize different memory models.

Malmberg, K. J. & Shiffrin, R. M. (2005, pdf.) The "one-shot" hypothesis for context storage. Journal of Experimental Psychology: Learning, Memory, and Cognition, 31(2), 322-336.

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.

Malmberg, K. J., Holden, J. E., & Shiffrin, R. M. (2004, .pdf). Modeling the effects of repetitions, similarity, and normative word frequency on judgments of frequency and recognition memory. Journal of Experimental Psychology: Learning, Memory, and Cognition, 30(2), 319-331.

Malmberg, K. J., Zeelenberg, R., & Shiffrin, R.M. (2004, .pdf). Turning up the Noise Or Turning Down the Volume? On the Nature of the Impairment of Episodic Recognition Memory by Midazolam. Journal of Experimental Psychology: Learning, Memory, and Cognition, 30(2), 540-549.

E. Hirshman, J. Fisher, T. Henthorn, J. Arndt, and A. Passannante (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 wordfrequency 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, retrievingeffectively- 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.

Sanborn, A. N., Malmberg, K. J., & Shiffrin, R. M. (2004, pdf.). High-level masking effects on perceptual identification. Vision Research, 44(12), 1427-1436.

The extent to which low- versus high-level visual information is used to identify briefly flashed words is assessed by varying both the mask that follows the flash and the information that discriminates two alternatives presented after the mask. Experiment 1 showed that @-signs masks caused observers to use high-level information but Experiment 2 showed removal of the mask reversed the results. We conclude that identification is based on several levels of information, the weighting of different types being determined by response strategies tuned to the nature of the task. Implications for theories of perceptually-driven implicit memory are discussed.

Steyvers, M. & Malmberg, K. J. (2003, pdf.). The effect of normative context variability on recognition memory, Journal of Experimental Psychology: Learning, Memory, and Cognition, 29(5), 760-766.

According to some theories of recognition memory (e.g., Dennis and Humphreys, 2001), the number of different contexts in which words appear determines how memorable individual occurences of words will be: A word that occurs in a small number 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, which is referred to here as context variability, that estimates the number of different contexts in which words appear in everyday life, and the present findings confirm for the first time the prediction that words low in context variability are better recognized than words that are high in context variability (on average).

Malmberg, K. J., Zeelenberg, R., & Shiffrin, R.M. (2003, pdf.) Modeling Midazolam's Effect on the Hippocampus and Recognition Memory. in S. Becker, S. Thrun, and K. Obermayer (Eds.). Advances in Neural Information Processing Systems 15, MIT Press, 75-82.

The benzodiazepine Midazolam causes dense, but temporary, anterograde amnesia, similar to that produced by hippocampal damage. Does the action of Midazolam on the hippocampus cause less storage, or less accurate storage, of information in episodic long-term memory? We used a simple variant of the REM model [18] to fit data collected by Hirshman, Fisher, Henthorn, Arndt, and Passannante [9] on the effects of Midazolam, study time, and normative word-frequency on both yes-no and remember-know recognition memory. That a simple strength model fit well was contrary to the expectations of Hirshman et al. More important, within the Bayesian based REM modeling framework, the data were consistent with the view that Midazolam causes less accurate storage, rather than less storage, of information in episodic memory.

Malmberg, K. J. & Nelson, T. O. (2003, pdf.). The word-frequency effect for recognition memory and the elevated-attention hypothesis. Memory & Cognition 31(1), 35-43.

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 elevatedattention 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.

Malmberg, K. J. (2002, pdf.). On the form of ROCs constructed from confidence ratings. Journal of Experimental Psychology: Learning, Memory, and Cognition, 28(2), 380-387.

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.

Malmberg, K. J. & Murnane, K. (2002, pdf.). List composition and the word-frequency effect for recognition memory. Journal of Experimental Psychology: Learning, Memory, and Cognition, 28(4), 616-630.

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 twoalternative 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.

Malmberg, K. J., Steyvers, M., Stephens, J. D., & Shiffrin, R. M. (2002, pdf.). Feature-frequency effects in recognition memory. Memory & Cognition, 30(4), 607-613.

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.

Murnane, K., Phelps, M. P., & Malmberg, K. (1999, pdf.). ICE: A theory of context dependent discrimination. Journal of Experimental Psychology: General. 128(4), 403-415.

813-974-7641, malmberg*cas.usf.edu

Department of Psychology, USF, 4202 East Fowler Ave, PCD 4118G, Tampa, FL, 33620