Recency Effect In Free Recall Research Articles

Holographic Declarative Memory: Distributional Semantics as the Architecture of Memory.

We demonstrate that the key components of cognitive architectures (declarative and procedural memory) and their key capabilities (learning, memory retrieval, probability judgment, and utility estimation) can be implemented as algebraic operations on vectors and tensors in a high-dimensional space using a distributional semantics model. High-dimensional vector spaces underlie the success of modern machine learning techniques based on deep learning. However, while neural networks have an impressive ability to process data to find patterns, they do not typically model high-level cognition, and it is often unclear how they work. Symbolic cognitive architectures can capture the complexities of high-level cognition and provide human-readable, explainable models, but scale poorly to naturalistic, non-symbolic, or big data. Vector-symbolic architectures, where symbols are represented as vectors, bridge the gap between the two approaches. We posit that cognitive architectures, if implemented in a vector-space model, represent a useful, explanatory model of the internal representations of otherwise opaque neural architectures. Our proposed model, Holographic Declarative Memory (HDM), is a vector-space model based on distributional semantics. HDM accounts for primacy and recency effects in free recall, the fan effect in recognition, probability judgments, and human performance on an iterated decision task. HDM provides a flexible, scalable alternative to symbolic cognitive architectures at a level of description that bridges symbolic, quantum, and neural models of cognition.

An application of multinomial processing tree models and Bayesian methods to understanding memory impairment

We model word-list learning over sequences of immediate and delayed free recall tasks to study the impact of memory impairment on episodic memory. We use a previously developed Multinomial Processing Tree (MPT) model of encoding, retrieval, and learning (Alexander et al., 2016), and apply it to behavioral data from thousands of patients tested tens of thousands of times in a cognitive disorders clinic. The patients were independently diagnosed, using the Functional Assessment Staging Test (FAST), into six stages of impairment. We apply hierarchical and latent-mixture versions of the MPT model to patients in each FAST stage, exploring individual differences among people and item-position effects across the word lists. Our results show clear and theoretically interpretable regularities in how model parameters change over item positions, corresponding to standard primacy and recency effects in free recall. Accordingly, we develop an extended model that directly incorporates theoretical assumptions about serial position. Inferences from this model allow us to reach conclusions about how learning, encoding, and retrieval processes change as memory impairment progresses.

Metacognition and learning about primacy and recency effects in free recall: The utilization of intrinsic and extrinsic cues when making judgments of learning

Although memory researchers know about primacy and recency effects, it is unclear whether students are aware of these effects and incorporate them when making judgments of learning (JOLs). The present research examined how participants use serial position information (extrinsic cues) when making JOLs after studying each item and showed that participants rely on the intrinsic qualities of the items and underestimate primacy and recency effects. However, when participants made JOLs prior to studying each item and engaged in multiple study-test sessions, their JOLs accurately reflected recall, as well as when serial position information was explicitly provided during the study phase. The findings are interpreted in a cue utilization framework and suggest that under certain conditions, participants can predict primacy and recency effects.

Evidence for Attentional Gradient in the Serial Position Memory Curve from Event-related Potentials

The occurrence of primacy versus recency effects in free recall is suggested to reflect either two distinct memory systems, or the operation of a single system that is modulated by allocation of attention and less vulnerable to interference. Behavioral and event-related brain potential (ERPs) measures were used to investigate the encoding substrates of the serial position curve and subsequent recall in young adults. Participants were instructed to remember lists of words consisting of 12 common nouns each presented once every 1.5 sec, with a recall signal following the last word to indicate that all remembered items should be written on paper. This procedure was repeated for 20 different word lists. Both performance and late ERP amplitudes reflected classic recall serial position effects. Greater recall and larger late positive component amplitudes were obtained for the primacy and recency items, with less recall and smaller amplitudes for the middle words. The late positive component was larger for recalled compared to unrecalled primacy items, but it did not differ between memory performance outcomes for the recency items. The close relationship between the enhanced amplitude and primacy retrieval supports the view that this positive component reflects one of a process series related to attentional gradient and encoding of events for storage in memory. Recency effects appear to index operations determined by the anticipation of the last stimulus presentation, which occurred for both recalled and unrecalled memory items. Theoretical implications are discussed.

Associative processes in immediate recency

Some theorists have argued that the immediate recency effect observed in free recall reflects the emptying out of the contents of a short-term memory buffer (Davelaar, Goshen-Gottstein, Ashkenazi, Haarmann, & Usher, 2005). Others have argued that immediate recency reflects the properties of temporal context used to cue free recall (Howard & Kahana, 2002). We examined immediate free recall of lists with an item from the middle of the list repeated at or near the end. If associative processes contribute to immediate recency, as predicted by the temporal context account, the neighbors of the initial presentation of the repeated item should show enhanced recall at the initial stages of immediate recall. Recall transitions early in output--and even the initiation of recall itself-showed evidence for temporally defined associations that resemble those observed in recall from long-term memory. These results have strong implications for models of the immediate recency effect in free recall.

Influences of environmental context on the recency effect in free recall

A total of 208 undergraduate participants incidentally encoded a list of seven pairs of familiar words in two experiments. A 30-sec calculation task was imposed before and after each pair was encoded. Participants received a free recall test 24 h (Experiment 1) or 10 min (Experiment 2) after the encoding session, under conditions in which the original environmental context was reinstated or not. The environmental context was manipulated in terms of the combination of the physical features of the room, the subsidiary task conducted, the experimenter (Experiment 1), or background music (Experiment 2). A recency effect appeared when the original environmental context was reinstated in both experiments, even though the IPI/RI ratio was too small to produce recency effects according to the ratio rule. The results imply that the environmental context should be taken into account for the recency effect.

Age dissociates recency and lag recency effects in free recall.

Age dissociates recency and lag recency effects in free recall.

Positional Distinctiveness and the Ratio Rule in Free Recall

The ratio rule relates the recency effect in free recall to the ratio of the duration of the inter-item presentation interval (IPI) and the retention interval (RI). Three experiments examined this ratio rule in an immediate memory setting. An approximately linear relationship was discovered to hold over ratios ranging from 1:12 to 12:1 (Experiment 1), and also for constant ratios ranging from 1:1 to 12:12 (Experiments 2 and 3). However, in contrast to a “true” ratio rule, recency systematically decreased with increases in absolute duration, despite a constant IPI to RI ratio. A new distinctiveness model is proposed that accurately predicts the reported empirical relationships. The model incorporates a precise definition of stimulus distinctiveness, based on the dimensional distinctiveness model, and includes a specific mechanism to account for how the distinctiveness of each item arises, based on the perturbation model.

Selective impairment of the “central executive” component of working memory: A single case study

We report the case of a head-injured patient (AM) with a specific short-term memory impairment. He did not show any deficit in long-term memory and presented no sign of either intellectual or frontal dysfunction. His spans for verbal and nonverbal material were reduced and he showed a lack of recency effect in free recall for visually presented words. We observed word length and phonological similarity effects as well as the abolition with articulatory suppression of the visual and auditory word length effect and of the visual phonological similarity effect, indicating that both the phonological store and the articulatory rehearsal mechanism were functioning. Furthermore, our investigations did not evidence any structural defect in either the control and planning functions of the central executive, or in its storage functions. The deficit AM presented on a verbal and nonverbal Brown-Peterson task, especially when the distractor tasks were more demanding, suggests that AM's central executive disposed of fewer processing resources. This resource reduction seemed to affect only short-term storage but not processing, and was interpreted as the consequence of strategic adaptation by the patient. Finally, the resource reduction did not cause interference on those divided attention tasks not requiring storage. As such, these results call for a more accurate specification of the allocation of resources in dual tasks.

On the Structure of Verbal Short-term Memory and its Functional Role in Sentence Comprehension: Evidence from Neuropsychology

Abstract We present a case of a patient with a disorder of short-term memory. BO has a reduced span (2 to 3 items), no recency effect in free recall, and rapid forgetting in Brown-Peterson tasks, establishing her as a patient with impaired short-term verbal memory functions. She shows no effect of either phonological similarity or word length in recall of auditory or written word lists, but some recency effect under recall-from-end conditions and better performance on Brown-Peterson tasks in an unfilled than in a filled condition. This pattern of performance is interpreted as being consistent with a primary disturbance of the articulatory rehearsal processes of S.T.M. and possibly some impairment of the phonological store (using Baddeley's 1986 terminology). Her aphasic disturbance—apraxia of speech—is also consistent with a disturbance of articulatory rehearsal. BO shows a retained ability to extract phonology from print, including an ability to apply sublexical grapheme-phoneme correspondences, thus ind...

Recency Effects and Temporal Distinctiveness: Dissociation between Free Recall and Memory for Position/Order

Temporal distinctiveness hypothesis argues that both short-term and long-term recency effects reflect the high distinctiveness of temporal (i.e., position and order) information in the recency portion. The present study tested this hypothesis. In Exp. 1, recency effects for free recall were compared to those for position/order memory in immediate, delayed, and continuous distractor conditions. Recency effects for both free recall and position/order memory disappeared in the delayed condition. In the continuous distractor condition, large recency effects for free recall reappeared (i.e., long-term recency effects), unaccompanied by the reappearance of recency effects for position/order memory. In Exp. 2, the temporal distinctiveness did not affect short-term recency effects in the immediate free recall. These results indicate that the temporal distinctiveness hypothesis is inadequate for short-term and long-term recency effects in free recall.

Primary and working memory functioning in Alzheimer-type dementia.

This paper reviews recent neuropsychological studies of primary-memory functioning in early Alzheimer-type dementia (AD) with specific reference to recent research on working memory. The deficits in primary memory follow a fairly distinct pattern with a comparatively unimpaired recency effect in free recall, a moderate impairment in memory span, and a more substantial impairment in short-term retention following distraction. The nature of these deficits is considered in relation to the Working Memory Model (Baddeley & Hitch, 1974). It is suggested that the Articulatory Loop System is functioning normally but that there is an impairment in the control processes of working memory.

Sources of recency effects in free recall.

When people memorize a list of words, they tend to recall items at the end of the list more often than those in the middle. This advantage for terminal items in recall is known as the recency effect. Recency effects have often been attributed to output from primary memory, a short-term memory buffer

Sources of recency effects in free recall.

Sources of recency effects in free recall.

Negative Recency in Final Free Recall: Encoding or Retrieval

In Experiment 1, seven groups of subjects were tested for final free recall of a series of previously studied lists. Four groups had been tested with initial recall after each list, and three of these groups performed orienting tasks during list presentation. The three other groups carried out the orienting tasks, but did not initially recall each list. Negative recency was found only for groups that initially recalled the lists, and the effect was similar for all orienting conditions. Experiment 2 replicated the positive recency effect in delayed recall of incidentally learned lists. In Experiment 3, negative recency in final free recall occurred for subjects who did not know the length of each list to be recalled. This pattern of results is consistent with a distinction of retrieval cues used to access recency and prerecency items, where the recency items are accessed chiefly on the basis of automatically encoded ordinal position attributes. Recency effects in free recall have been cited as support for multiprocess models of memory. Typically, when each list in a series of lists of unrelated words is recalled immediately after presentation with no restriction on output order, terminal items are recalled better than are words in the middle of a list. However, when final free recall of all lists is attempted following recall of the last list in the series, the proportion of terminal items recalled is lower than that of middle items (Craik, 1970). The divergent recall patterns of the terminal items in immediate and final recall suggest two processes underlie performance in those situations. The positive recency effect in immediate recall and the negative recency effect in final recall are consistent with a multistore model of memory. According to this model, terminal items are read out of primary memory in immediate recall and consequently are less likely to be transferred to secondary memory from which final recall is tested. Results from several paradigms, however, argue against an explana

Long-Term Recency Effects in Free Recall

Although Tzeng (1973) and Bjork and Whitten (1974) have obtained positive recency effects in free recall using a procedure designed to eliminate any component of short-term storage, their procedures may not have truly cleared shortterm storage. In the present experiment, subjects were presented with four lists for free recall, each list composed of seven sets of noun triples. Presentation was either visual or auditory, and subjects counted backward by sevens before and after each item. Even with short-term storage thus cleared, recency effects were obtained equally for both modalities. No effect of serial position was found in a final test of free recall.

Free recall and complexity of pictorial stimuli

In order to explore variables underlying primacy and recency effects in free recall of pictorial material, norms were developed using 120 subjects who rated the vividness and complexity of slides. Two experiments were then run in which two levels of each of these variables (extreme high and low ratings) were factorially combined. In the first experiment 24 subjects were shown three mixed lists, two short and one long (consisting of materials of all four combinations of vividness and complexity), and in the second experiment 12 subjects were shown four pure lists (consisting of materials of a single type). Analysis of variance showed list length in the mixed list experiment and complexity in both experiments to be strong determinants of recall. Greatest recall was for items of low complexity in short lists. Weak, but statistically significant, serial position effects were evident, particularly for less complex items. The effects of primacy and recency seem to decrease with increasing complexity of visual materials, perhaps because of the greater difficulty in rehearsing more complex pictures either verbally or iconically.

The effect of articulatory suppression in free recall

When subjects are required to utter a series of redundant speech sounds while memorizing lists of words, performance is impaired and the effect of phonemic similarity is reduced. If the recency effect in free recall is based upon phonemic coding then it should be very susceptible to the effects of such a procedure. Two experiments therefore explored the influence of articulatory suppression on performance in free recall. Both produced reliable effects of suppression, but neither showed the predicted interaction between suppression and serial position. It is suggested that the recency effect does not reflect a short-term phonemic store.

Positive and negative recency effects in free recall learning

This study examined the relationship between the magnitude of the positive recency effect in immediate free recall (IFR) and the magnitude of the negative recency effect in final free recall (FFR). Subjects learned 10 lists, followed by a FFR test. Across Lists 1–8 (each 21 words in length) there was an increase in positive recency in IFR and a concomitant increase in negative recency in FFR. There was no negative recency in FFR for List 9 which was a short list (12 words), and List 10 (21 words). These results, plus order of recall data, provide support for the hypothesis that negative recency is the product of a strategy wherein subjects learn to superficially encode end items in IFR because this is sufficient to guarantee their immediate recall.

Recency-sensitive retrieval processes in long-term free recall

In several experiments, each presentation of a to-be-remembered item in a free-recall list was both preceded and followed by a distracting activity and recall was delayed by an additional period of distracting activity. Pronounced long-term effects of recency were obtained, the standard short-term memory interpretation of recency effects in free recall notwithstanding. The results are interpreted as reflecting retrieval processes that are obscured by procedural characteristics of typical free-recall experiments.