Critique of the retrieval/deblurring assumptions of the theory of distributed associative memory.

Critiques the retrieval assumptions proposed by S. Lewandowsky and B. B. Murdock (see record 1989-14457-001) in their application of Murdock's theory of distributed associative memory (TODAM) to problems in serial-order recall. Two different methods for "deblurring" the products of retrieval are described, along with simulations appropriate for each. It is demonstrated that the deblurring assumptions used by Lewandowsky and Murdock in their simulation version of the model, although appropriate for some aspects of serial-anticipation learning, provide an inadequate account of general serial recall and, in fact, predict several trends that are inconsistent with known data. The analytic version of the model is considered and some additional problems are noted. Overall, the deblurring assumptions critically affect the performance of TODAM, and it is these assumptions rather than the model per se that determine a sizable proportion of its behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Item and associative recognition with precuing and postcuing.

M. Duncan & B. B. Murdock (2000) compared precued and postcued item recognition and serial recall showing precued-postcued differences for item recognition but not for serial recall. Precuing and postcuing refer to 2 conditions in which the instructions as to the type of recall test following the presentation of short lists of items is given before or after the list presentation. This methodology was extended here to a paired-associate task. In 2 experiments, short lists of paired associates were presented followed by single-item, old-new, or intact-rearranged pair recognition tests; test type was precued or postcued. A fast or slow presentation rate was used to discourage or encourage mediators. TODAM2 (a theory of distributed associative memory) predicts that there should be little or no cuing differences regardless of whether subjects use mediators to remember the pairs. As predicted the recognition data were essentially identical for the precued and postcued conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Top-down controlled, delayed selection in the attentional blink.

In a previous study, it was shown that the attentional blink (AB)--the failure to recall the 2nd of 2 visual targets (T1 and T2) presented within 500 ms in rapid serial visual presentation--is reduced when T2 is preceded by a distractor that shares a feature with T2 (e.g., color; Nieuwenstein, Chun, van der Lubbe & Hooge, 2005). Here, this cuing effect is shown to be contingent on attentional set. For example, a red distractor letter preceding a green digit T2 is an effective cue when the task is to look for red and green digits, but the same red cue is relatively ineffective when the task is to look for only green digits or when the color of T2 is not specified. It is also shown that cuing is not interrupted by a distractor intervening between the cue and T2. These findings provide evidence for a contingent, delayed selection account of the AB. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Forward and backward recall: Different retrieval processes.

Recall direction is known to be an important determinant of serial recall performance: For example, accuracy is often greater for forward recall than backward recall, and forward recall typically exhibits extensive primacy but little recency, with the reverse arrangement for backward recall. Although some of the differences between recall directions can be accommodated by models that postulate a single retrieval process, recent evidence appears to favor the existence of 2 distinct retrieval processes, 1 for forward and 1 for backward recall. Five experiments reported in this article were aimed at illuminating these 2 putative processes. Tasks that interfered with the formation of interitem associations at study were found to disrupt forward but not backward recall, whereas tasks that altered the visual–spatial characteristics of the study material affected backward but not forward recall. It was proposed that forward recall is largely based on interitem associations, whereas backward recall relies on a visual–spatial representation of the study material. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

TODAM2: A model for the storage and retrieval of item, associative, and serial-order information.

Presents an extended version of the convolution–correlation memory model TODAM (theory of distributed associative memory) that not only eliminates some of the inadequacies of previous versions but also provides a unified treatment of item, associative, and serial-order information. The chunking model extended the basic convolution–correlation formalism by using multiple convolutions, n-grams (multiple autoassociations of sums of item vectors), and chunks (sums of n-grams) to account for chunking and serial organization. TODAM2 extends the chunking model by including rn-grams (reduced n-grams), labels, and "lebals" (the involution or mirror image of a label) to provide a general model for episodic memory. For paired associates, it is assumed that Ss store only labeled n-grams and lebaled rn-grams. It is shown that the model is broadly consistent with a number of major empirical paired-associate and serial-order effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contextual variability and serial position effects in free recall.

In immediate free recall, words recalled successively tend to come from nearby serial positions. M. J. Kahana (see record 1996-93836-009) documented this effect and showed that this tendency, which the authors refer to as the lag recency effect, is well described by a variant of the search of associative memory (SAM) model (J. G. W. Raaijmakers & R. M. Shiffrin, 1980, 1981). In 2 experiments, participants performed immediate, delayed, and continuous distractor free recall under conditions designed to minimize rehearsal. The lag recency effect, previously observed in immediate free recall, was also observed in delayed and continuous distractor free recall. Although two-store memory models, such as SAM, readily account for the end-of-list recency effect in immediate free recall, and its attenuation in delayed free recall, these models fail to account for the long-term recency effect. By means of analytic simulations, the authors show that both the end of list recency effect and the lag recency effect, across all distractor conditions, can be explained by a single-store model in which context, retrieved with each recalled item, serves as a cue for subsequent recalls. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Forced-choice associative recognition: Implications for global-memory models.

Associative recognition requires Ss to discriminate intact from rearranged test pairs. In a 3-alternative forced-choice procedure, an intact test pair is tested against 2 rearranged distractors which may overlap, by sharing a common word in each test pair alternative (OLAP), or may not share words (NOLAP). With the exception of B. B. Murdock's (see record 1983-04936-001) theory of distributed associative memory (TODAM), current global matching models predict that forced-choice performance will be better for OLAP than for NOLAP test trials. TODAM can predict either an OLAP advantage or no difference between OLAP and NOLAP test conditions. The performance of the models is produced by fundamental statistical properties, and with the exception of TODAM, the OLAP advantage cannot be eliminated by varying parameters. Results of 3 experiments, however, show a NOLAP advantage. The implications of these results for global matching models and the relationship between recall and recognition are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Short-term memory in autism spectrum disorder.

Three experiments examined verbal short-term memory in comparison and autism spectrum disorder (ASD) participants. Experiment 1 involved forward and backward digit recall. Experiment 2 used a standard immediate serial recall task where, contrary to the digit-span task, items (words) were not repeated from list to list. Hence, this task called more heavily on item memory. Experiment 3 tested short-term order memory with an order recognition test: Each word list was repeated with or without the position of 2 adjacent items swapped. The ASD group showed poorer performance in all 3 experiments. Experiments 1 and 2 showed that group differences were due to memory for the order of the items, not to memory for the items themselves. Confirming these findings, the results of Experiment 3 showed that the ASD group had more difficulty detecting a change in the temporal sequence of the items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comprehension-Based Versus Production-Internal Feedback in Planning Spoken Words: A Rejoinder to Rapp and Goldrick (2004).

WEAVER + + has no backward links in its form-production network and yet is able to explain the lexical and mixed error biases and the mixed distractor latency effect. This refutes the claim of B. Rapp and M. Goldrick (2000) that these findings specifically support production-internal feedback. Whether their restricted interaction account model can also provide a unified account of the error biases and latency effect remains to be shown. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory for serial order revisited.

The critiques by D. J. Mewhort et al (see record 1994-36081-001) and J. S. Nairne and I. Neath (see record 1994-36082-001) identified at least 6 potentially serious problems with S. Lewandowsky and B. B. Murdock's (see record 1989-14457-001) Theory of Distributed Associative Memory (TODAM) model of memory for serial order. It is shown that the flaws attributed to the memory component of TODAM are less serious than claimed, whereas the problems attributed to the response selection stage necessitated a process implementation of the previously unspecified deblurring mechanism. The deblurring process, implemented by a dynamic autoassociative network, is shown to handle most of the problems identified by the critics without imperiling TODAM's ability to handle basic serial position data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative priming by targets and distractors during rapid serial visual presentation: Does word meaning survive the attentional blink?

In 5 experiments, 432 college students viewed lists of words containing 2 targets (Target 1 [T1] and Target 2 [T2]) presented by rapid serial visual presentation at 10 words per second. Identification of T1 caused a 500-ms impairment in the identification of T2 (the attentional blink [AB]). Improved recall of T2 was observed throughout the time course of the AB when T2 was a strong associate of either T1 or a priming distractor (PD). When participants ignored T1, the AB was eliminated, but the amount of priming was not affected. Priming of T2 by PD was temporary (100–200 ms after the onset of PD). Although target priming and distractor priming both survived the AB, the 2 forms of priming appeared to have different bases. In contrast to priming by PD, priming by T1 was larger, modulated by backward associative strength, and longer lasting. Priming and the AB are hypothesized to result from on-line attentional processes, but recall from RSVP lists is also influenced by off-line memory processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Explaining the irrelevant-sound effect: Temporal distinctiveness or changing state?

Task-irrelevant background sound disrupts serial recall. One account of this effect assumes that irrelevant events close to or during the presentation of a to-be-remembered list will interfere by disrupting temporal codes. A second account predicts that disruption will be greatest when the burden on rehearsal is high, as order cues in the auditory sequence interfere with those in the memory set. The authors tested these predictions by restricting the sound to different phases of the serial recall task. Sound presented just before the list and sound presented early in list presentation did not disrupt recall, but sound presented late in the list or after list presentation produced significant disruption. Sound presented after the list was more disruptive of recall for early list items than sound presented at the same time as those items. An account based on disruption of serial rehearsal, not the disruption of temporal codes, is supported. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Concrete words are easier to recall than abstract words: Evidence for a semantic contribution to short-term serial recall.

Immediate serial recall and maximal speech rate were assessed for concrete and abstract words differing in length. Experiment 1 showed large advantages for spoken recall of concrete words that were independent of speech rate. Experiment 2 showed an equivalent effect with written, rather than spoken, recall. Experiment 3 showed that the concreteness effect was still present when recall was backward rather than forward. In all 3 experiments, concrete words enjoyed an advantage that was roughly constant across all serial positions (with the possible exception of the 1st and last items). Experiment 4 used a matching-span procedure and showed that when there was no requirement for linguistic output, the effect of concreteness (but not the effect of word length) was eliminated. It is argued that semantic coding exerts powerful effects in verbal short-term memory tasks that have generally been underestimated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interfering with the central executive by means of a random interval repetition task

Four dual-task experiments are reported in which a short-term memory task is performed concurrently with a random interval repetition task, which was designed to interfere with functions normally attributed to the central executive in the working memory model of Baddeley and Hitch (1974). The task was found to interfere with supra-span serial recall and with backward memory span, but did not disrupt performance on a forward-memory-span task. The effects were observed in dissociation with effects of articulatory suppression and matrix tapping, so that the locus of the effects of the new task is not due to the slave systems. In addition, single-task random-interval repetition performance was sampled and compared to performance in the dual-task conditions of all four experiments. Although quality of tapping performance differed between the single-task and the dual-task conditions, it was not related to recall performance. All the results are discussed with reference to the working memory model.     

Negative priming for spatial locations: Identity mismatching, not distractor inhibition.

Negative priming (NP) is commonly thought to occur because distractor inhibition is necessary for target selection (the distractor inhibition hypothesis). Contrary to this account, the selection of a target in the preceding trial is shown to be neither necessary (Exp 1) nor sufficient (Exps 2 and 3) for NP in a target localization task modeled after S. P. Tipper et al (see record 1991-00251-001). Exps 4 and 5 provide further evidence against the distractor inhibition hypothesis and support an alternative mismatching account: NP in the spatial selection task apparently results from a change in the symbol bound to a given location (D. Kahneman et al; see record 1992-37866-001), rather than a change in the status of that location from distractor to target (Tipper et al). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Role of Constraints in Expert Memory.

A great deal of research has been devoted to developing process models of expert memory. However, K. J. Vicente and J. H. Wang (1998) proposed (a) that process theories do not provide an adequate account of expert recall in domains in which memory recall is a contrived task and (b) that a product theory, the constraint attunement hypothesis (CAH), has received a significant amount of empirical support. We compared 1 process theory (the template theory; TT; F. Gobet & H. A. Simon, 1996c) with the CAH in chess. Chess players (N=36) differing widely in skill levels were required to recall briefly presented chess positions that were randomized in various ways. Consistent with TT, but inconsistent with the CAH, there was a significant skill effect in a condition in which both the location and distribution of the pieces were randomized. These and other results suggest that process models such as TT can provide a viable account of expert memory in chess. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Word-frequency effects on short-term memory tasks: evidence for a redintegration process in immediate serial recall

Four experiments investigated the mechanisms responsible for the advantage enjoyed by high-frequency words in short-term memory tasks. Experiment 1 demonstrated effects of word frequency on memory span that were independent of differences in speech rate. Experiments 2 and 3 showed that word frequency has an increasing effect on serial recall across serial positions, but Experiment 4 showed that this effect was abolished for backward recall. A model that includes a redintegration process that operates to "clean up" decayed short-term memory traces is proposed, and the multinomial processing tree model described by R. Schweickert (1993) is used to provide a quantitative fit to data from Experiments 2, 3, and 4.     

Implicit learning of unique and ambiguous serial transitions in the presence and absence of a distractor task.

Three experiments investigated the effects of task load, time of secondary task onset, and response-stimulus time interval on direct and indirect measures of learning in the M. J. Nissen and P. Bullemer (see record 1987-13436-001) task. Exp 1 demonstrated that both unique and ambiguous serial transitions can be learned in the absence and presence of an attentional distractor task. Exp 2 showed that the time of secondary task onset affects the degree to which unique and ambiguous serial transitions are learned. Exp 3 demonstrated that the learning of a sequential transition is affected by the length of the time interval between the response to a stimulus and the presentation of the next stimulus. The findings replicate and extend results reported by A. Cohen et al (see record 1990-08941-001) and provide important empirical constraints for a process model of implicit serial learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recall and measures of memory organization.

Investigated in 2 experiments with 180 undergraduates the relations between recall performance and specific network and spatial representations of memory in serial and free recall paradigms. The structural representations were derived from relatedness ratings by using the alternating least squares scaling, Kruskal-Young-Shepard-Torgerson (J. B. Kruskal and M. Wish, 1978), and Kruskal (1977) multidimensional scaling algorithms and the Pathfinder network scaling algorithm. Results indicate that in the serial recall task, list organization defined by the network yielded faster learning than organization defined by multidimensional space, although both types of organizations yielded increases in the number of items recalled. In free recall, the network representations were predictive of recall order even with the original ratings partialed out. The spatial representations, however, were not independently predictive of recall. It is suggested that Pathfinder networks better capture the relations important for recall than do spatial representations. Also, Pathfinder networks provide information about memory organization that is not directly available in pairwise ratings. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)