The role of episodic memory sampling in evaluation.

Many models of choice assume that people retrieve memories of past experiences and use them to guide evaluation and choice. In this paper, we examine whether samples of recalled past experiences do indeed underpin our evaluations of options. We showed participants sequences of numerical values and asked them to recall as many of those values as possible and also to state how much they would be willing to pay for another draw from the sequence. Using Bayesian mixed effects modeling, we predicted participants' evaluation of the sequences at the group level from either the average of the values they recalled or the average of the values they saw. Contrary to the predictions of recall-based models, people's evaluations appear to be sensitive to information beyond what was actually recalled. Moreover, we did not find consistent evidence that memory for specific items is sufficient to predict evaluation of sequences. We discuss the implications for sampling models of memory and decision-making and alternative explanations.

The role of rehearsal and reminding in the recall of categorized word lists.

Most theories of free recall emphasize the importance of retrieval in explaining temporal and semantic regularities in recall; rehearsal mechanisms are often absent or limit rehearsal to a subset of what was last rehearsed. However, in three experiments using the overt rehearsal method, we show clear evidence that just-presented items act as retrieval cues during encoding (study-phase retrieval) with prior related items rehearsed despite well over a dozen intervening items. Experiment 1 examined free recall of categorized and uncategorized lists of 32 words. In Experiments 2 and 3, we presented categorized lists of 24, 48, and 64 words for free recall or cued recall, with the category exemplars blocked in successive list positions (Experiment 2) or randomized throughout the list (Experiment 3). The probability of rehearsing a prior word was affected by its semantic similarity to the just-presented item, and the frequency and recency of its prior rehearsals. These rehearsal data suggest alternative interpretations to well-known recall phenomena. With randomized designs, the serial position curves were reinterpreted by when words were last rehearsed (which contributed to the list length effects), and semantic clustering and temporal contiguity effects at output were reinterpreted by whether words were co-rehearsed during study. The contrast with the blocked designs suggests that recall is sensitive to the relative (not absolute) recency of targeted list items. We discuss the benefits of incorporating rehearsal machinery into computational models of episodic memory, and suggest that the same retrieval processes that generate the recalls are used to generate the rehearsals.

Remembering St. Louis individual-structural violence and acute bacterial infections in a historical anatomical collection.

Incomplete documentary evidence, variable biomolecular preservation, and limited skeletal responses have hindered assessment of acute infections in the past. This study was initially developed to explore the diagnostic potential of dental calculus to identify infectious diseases, however, the breadth and depth of information gained from a particular individual, St. Louis Individual (St.LI), enabled an individualized assessment and demanded broader disciplinary introspection of ethical research conduct. Here, we document the embodiment of structural violence in a 23-year-old Black and/or African American male, who died of lobar pneumonia in 1930s St. Louis, Missouri. St.LI exhibits evidence of systemic poor health, including chronic oral infections and a probable tuberculosis infection. Metagenomic sequencing of dental calculus recovered three pre-antibiotic era pathogen genomes, which likely contributed to the lobar pneumonia cause of death (CoD): Klebsiella pneumoniae (13.8X); Acinetobacter nosocomialis (28.4X); and Acinetobacter junii (30.1X). Ante- and perimortem evidence of St.LI's lived experiences chronicle the poverty, systemic racism, and race-based structural violence experienced by marginalized communities in St. Louis, which contributed to St.LI's poor health, CoD, anatomization, and inclusion in the Robert J. Terry Anatomical Collection. These same embodied inequalities continue to manifest as health disparities affecting many contemporary communities in the United States.

Distinguishing the Impact of Age on Semantic and Nonsemantic Associations in Episodic Memory.

OBJECTIVES: Refreshing, or the act of briefly foregrounding recently presented but now perceptually absent representations, has been identified as a possible source of age differences in working memory and episodic memory. We investigated whether the refreshing deficit contributes to the well-known age-related deficit for retrieving nonsemantic associations, but has no impact on existing semantic associations. METHOD: Younger and older adults judged the relatedness of stimulus word pairs (e.g., pink-blue or pink-cop) after repeating or refreshing one of the words. During a later source recognition memory test, participants determined whether each item recognized as old was presented on the left or right (nonsemantic source memory) and presented in a related or unrelated pair (semantic source memory). The data were analyzed using a hierarchical Bayesian implementation of a multinomial model of multidimensional source memory. RESULTS: Neither age group exhibited a refreshing benefit to nonsemantic or semantic source memory parameters. There was a large age difference in nonsemantic source memory, but no age difference in semantic source memory. DISCUSSION: The study suggests that the nature of the association is most important to episodic memory performance in older age, irrespective of refreshing, such that source memory is unimpaired for semantically meaningful information.

Control processes in short-term storage: Retrieval strategies in immediate recall depend upon the number of words to be recalled.

According to the Atkinson and Shiffrin (1968) model, control processes in the short-term memory store determine the selection of different storage, search, and retrieval strategies. Although rehearsal is the most studied short-term control process, it is necessary to specify the different retrieval strategies available for participants to use in searching for and outputting from short-term or immediate memory, as well as the degree to which participants can flexibly select different retrieval strategies for recalling rehearsed and unrehearsed materials. In three experiments we examined retrieval strategies in tests of immediate free recall (Exp. 1), immediate serial recall (ISR; Exp. 2), and a variant of ISR that we call ISR-free (Exp. 3). In each experiment, participants were presented with very short lists of four, five, or six words and were instructed to recall one, two, three, or all of the items from each list. Neither the list length nor the number of to-be-recalled items was known in advance. The serial position of the first item recalled in all three tasks depended on the number of to-be-recalled items. When only one or two items were to be recalled, participants tended to initiate recall with the final or penultimate list item, respectively; when participants were required to recall as many list items as possible, they tended to initiate recall with the first list item. These findings show that different retrieval strategies exist for rapidly searching for different numbers of items from immediate memory, and they confirm that participants have some control over their output order, as measured by the first items recalled.

RECAPP-XPR: A smartphone application for presenting and recalling experimentally controlled stimuli over longer timescales.

We report two experiments that used smartphone applications for presenting and recalling verbal stimuli over extended timescales. In Experiment 1, we used an iPhone application that we had developed, called RECAPP-XPR, to present 76 participants with a single list of eight words presented at a rate of one word every hour, followed by a test of free recall an hour later. The experiment was exceptionally easy to schedule, taking only between 5 and 10 min to set up using a web-based interface. RECAPP-XPR randomly samples the stimuli, presents the stimuli, and collects the free recall data. The stimuli disappear shortly after they have been presented, and RECAPP-XPR collects data on when each stimulus was viewed. In Experiment 2, the study was replicated using the widely used image-sharing application Snapchat. A total of 197 participants were tested by 38 student experimenters, who manually presented the stimuli as "snaps" of experimentally controlled stimuli using the same experimental rates that had been used in Experiment 1. Like all snaps, these stimuli disappeared from view after a very short interval. In both experiments, we observed significant recall advantages for the first and last list items (primacy and recency effects, respectively), and there were clear tendencies to make more transitions at output between near-neighboring items, with a forward-ordered bias, consistent with temporal contiguity effects. The respective advantages and disadvantages of RECAPP-XPR and Snapchat as experimental software packages are discussed, as is the relationship between single-study-list smartphone experiments and long-term recency studies of real-world events.

Benchmarks for models of short-term and working memory.

Any mature field of research in psychology-such as short-term/working memory-is characterized by a wealth of empirical findings. It is currently unrealistic to expect a theory to explain them all; theorists must satisfice with explaining a subset of findings. The aim of the present article is to make the choice of that subset less arbitrary and idiosyncratic than is current practice. We propose criteria for identifying benchmark findings that every theory in a field should be able to explain: Benchmarks should be reproducible, generalize across materials and methodological variations, and be theoretically informative. We propose a set of benchmarks for theories and computational models of short-term and working memory. The benchmarks are described in as theory-neutral a way as possible, so that they can serve as empirical common ground for competing theoretical approaches. Benchmarks are rated on three levels according to their priority for explanation. Selection and ratings of the benchmarks is based on consensus among the authors, who jointly represent a broad range of theoretical perspectives on working memory, and they are supported by a survey among other experts on working memory. The article is accompanied by a web page providing an open forum for discussion and for submitting proposals for new benchmarks; and a repository for reference data sets for each benchmark. (PsycINFO Database Record

Benchmarks provide common ground for model development: Reply to Logie (2018) and Vandierendonck (2018).

We respond to the comments of Logie and Vandierendonck to our article proposing benchmark findings for evaluating theories and models of short-term and working memory. The response focuses on the two main points of criticism: (a) Logie and Vandierendonck argue that the scope of the set of benchmarks is too narrow. We explain why findings on how working memory is used in complex cognition, findings on executive functions, and findings from neuropsychological case studies are currently not included in the benchmarks, and why findings with visual and spatial materials are less prevalent among them. (b) The critics question the usefulness of the benchmarks and their ratings for advancing theory development. We explain why selecting and rating benchmarks is important and justifiable, and acknowledge that the present selection and rating decisions are in need of continuous updating. The usefulness of the benchmarks of all ratings is also enhanced by our concomitant online posting of data for many of these benchmarks. (PsycINFO Database Record

Towards augmented human memory: Retrieval-induced forgetting and retrieval practice in an interactive, end-of-day review.

The authors report 6 experiments that examined the contention that an end-of-day review could lead to augmentation in human memory. In Experiment 1, participants in the study phase were presented with a campus tour of different to-be-remembered objects in different university locations. Each to-be-remembered object was presented with an associated specific comment. Participants were then shown the location name and photographs of half of the objects from half of the locations, and they were asked to try to name the object and recall the associated comment specific to each item. Following a filled delay, participants were presented with the name of each campus location and were asked to free recall the to-be-remembered objects. Relative to the recall from the unpracticed location categories, participants recalled the names of significantly more objects that they practiced (retrieval practice) and significantly fewer unpracticed objects from the practiced locations (retrieval-induced forgetting, RIF). These findings were replicated in Experiment 2 using a campus scavenger hunt in which participants selected their own stimuli from experimenter's categories. Following an examination of factors that maximized the effects of RIF and retrieval practice in the laboratory (Experiment 3), the authors applied these findings to the campus scavenger hunt task to create different retrieval practice schedules to maximize and minimize recall of items based on experimenter-selected (Experiment 4) and participant-selected items using both category-cued free recall (Experiment 5) and item-specific cues (Experiment 6). Their findings support the claim that an interactive, end-of-day review could lead to augmentation in human memory. (PsycINFO Database Record

Near-independent capacities and highly constrained output orders in the simultaneous free recall of auditory-verbal and visuo-spatial stimuli.

Three experiments examined the immediate free recall (IFR) of auditory-verbal and visuospatial materials from single-modality and dual-modality lists. In Experiment 1, we presented participants with between 1 and 16 spoken words, with between 1 and 16 visuospatial dot locations, or with between 1 and 16 words and dots with synchronized onsets. We found that for dual-modality lists (a) overall performance, initial recalls, and serial position curves were largely determined by the within-modality list lengths, (b) there was only a small degree of dual-task trade-off (that was limited to the visuospatial items), and (c) there were strongly constrained output orders: participants tended to alternate between words and dots from equivalent or neighboring serial positions. In Experiments 2 and 3, we compared lists of 6 single-modality items with dual-modality lists of 6 words and 6 dots with synchronous or alternating onsets (Experiment 2), or random but asynchronous onsets (Experiment 3). In all 3 dual-modality conditions, we again found only a small trade-off in visuospatial (but not verbal) IFR performance. There were similarly highly constrained output orders with the synchronous and alternating onsets, and these patterns were present but attenuated with the randomized onsets. We propose that both auditory-verbal and visuospatial list items are associated with a common temporal episodic context that is used to guide cross-modal retrieval, and we speculate that the limited, asymmetric interference could arise because the less variable representations of the dots share only a relatively small subset of features with the more variable representations of the words. (PsycINFO Database Record

Serial position, output order, and list length effects for words presented on smartphones over very long intervals.

Three experiments examined whether or not benchmark findings observed in the immediate retrieval from episodic memory are similarly observed over much greater time-scales. Participants were presented with experimentally-controlled lists of words at the very slow rate of one word every hour using an iPhone recall application, RECAPP, which was also used to recall the words in either any order (free recall: Experiments 1 to 3) or the same order as presented (serial recall: Experiment 3). We found strong temporal contiguity effects, weak serial position effects with very limited recency, and clear list length effects in free recall; clear primacy effects and classic error gradients in serial recall; and recency effects in a final two-alternative forced choice recognition task (Experiments 2 and 3). Our findings extend the timescales over which temporal contiguity effects have been observed, but failed to find consistent evidence for strong long-term recency effects with experimenter-controlled stimuli.

Common modality effects in immediate free recall and immediate serial recall.

In 2 experiments, participants were presented with lists of between 2 and 12 words for either immediate free recall (IFR) or immediate serial recall (ISR). Auditory recall advantages at the end of the list (modality effects) and visual recall advantages early in the list (inverse modality effects) were observed in both tasks and the extent and magnitude of these effects were dependent upon list length. Both tasks displayed modality effects with short lists that were large in magnitude but limited to the final serial position, consistent with those observed in the typically short lists used in ISR, and both tasks displayed modality effects with longer lists that were small in magnitude and more extended across multiple end-of-list positions, consistent with those observed in the typically longer lists used in IFR. Inverse modality effects were also observed in both tasks at early list positions on longer lengths. Presentation modality did not affect where recall was initiated, but modality effects were greatest on trials where participants initiated recall with the first item. We argue for a unified account of IFR and ISR. We also assume that the presentation modality affects the encoding of all list items, and that modality effects emerge due to the greater resistance of auditory items to output interference. (PsycINFO Database Record

Beginning at the beginning: Recall order and the number of words to be recalled.

When participants are asked to recall a short list of words in any order that they like, they tend to initiate recall with the first list item and proceed in forward order, even when this is not a task requirement. The current research examined whether this tendency might be influenced by varying the number of items that are to be recalled. In 3 experiments, participants were presented with short lists of between 4 and 6 words and instructed to recall 1, 2, 3, or all of the items from the lists. Data were collected using immediate free recall (IFR, Experiment 1), immediate serial recall (ISR, Experiment 2), and a variant of ISR that we call ISR-free (Experiment 3), in which participants had to recall words in their correct serial positions but were free to output the words in any order. For all 3 tasks, the tendency to begin recall with the first list item occurred only when participants were required to recall as many items from the list as they could. When participants were asked to recall only 1 or 2 items, they tended to initiate recall with end-of-list items. It is argued that these findings show for the first time a manipulation that eliminates the initial tendency to recall in forward order, provide some support for recency-based accounts of IFR and help explain differences between single-response and multiple-response immediate memory tasks. (PsycINFO Database Record

The effect of selective attention and a stimulus prefix on the output order of immediate free recall of short and long lists.

Participants tend to initiate immediate free recall (IFR) of short lists of words with the first word in the list (Serial Position 1 [SP1]) and then proceed in forward serial order. Two potential explanations for this finding were examined: that the first items have increased selective attention (Experiment 1A and 1B) and enhanced temporal distinctiveness (Experiment 2) relative to subsequent list items. In Experiments 1A and 1B, participants were presented with lists of colored words for IFR. The experimental group was told that some trials would contain a red word and that when this occurred, they should output this word first in recall before recalling as many other words as they could. This instruction was designed to shift attention away from SP1 and toward the red item. The control group participants received identical stimuli but were unaware of the importance of the colored words and had no output order constraints. The overall recall of SP1 was not greatly affected in either experiment. In Experiment 2, participants were presented with lists containing between 2 and 12 words. Half of the trials contained a triple word stimulus prefix. For short lists in IFR, the overall recall of SP1 and the tendency to initiate recall with SP1 were reduced but far from eliminated by the stimulus prefix. We argue that our findings may be explained within a grouping interpretation in which the tendency to initiate recall with the first to-be-remembered item may reflect participants' tendency to output the first word in a highly salient participant-determined group.

Can the effects of temporal grouping explain the similarities and differences between free recall and serial recall?

Temporal grouping can provide a principled explanation for changes in the serial position curves and output orders that occur with increasing list length in immediate free recall (IFR) and immediate serial recall (ISR). To test these claims, we examined the effects of temporal grouping on the order of recall in IFR and ISR of lists of between one and 12 words. Consistent with prior research, there were significant effects of temporal grouping in the ISR task with mid-length lists using serial recall scoring, and no overall grouping advantage in the IFR task with longer list lengths using free recall scoring. In all conditions, there was a general tendency to initiate recall with either the first list item or with one of the last four items, and then to recall in a forward serial order. In the grouped IFR conditions, when participants started with one of the last four words, there were particularly heightened tendencies to initiate recall with the first item of the most recent group. Moreover, there was an increased degree of forward-ordered transitions within groups than across groups in IFR. These findings are broadly consistent with Farrell's model, in which lists of items in immediate memory are parsed into distinct groups and participants initiate recall with the first item of a chosen cluster, but also highlight shortcomings of that model. The data support the claim that grouping may offer an important element in the theoretical integration of IFR and ISR.

Predictors of mortality for people aged over 65 years receiving mental health care for delirium in a South London Mental Health Trust, UK: a retrospective survival analysis.

BACKGROUND: Delirium is a common phenomenon in older people. Using a large mental health care data resource, we investigated mortality rates and predictors of mortality following delirium in older people. METHODS: The South London and Maudsley NHS Foundation Trust (SLAM) Clinical Record Interactive Search (CRIS) was used to retrieve anonymised data on patients known to mental health services who were over 65 years of age and received a diagnosis of delirium during a 3-year period. Age-standardised and gender-standardised mortality rates (SMRs) were calculated, and predictors of survival were investigated considering demographic factors, health status rated on the Health of the National Outcome Scale (HoNOS), cognitive function and previous or contemporaneous diagnosed dementia. RESULTS: In 974 patients with delirium, 1- and 3-year mortality rates were 37.2 and 54.9% respectively, representing an SMR of 4.7 overall (95% CI: 4.3-5.1). SMR was 5.2 (95% CI: 4.6-5.7) for patients with delirium without prior dementia; SMR was 4.1 (95% CI: 3.6-4.7) for patients with dementia preceding delirium and 2.2 (2.0-2.5) excluding deaths within 6 months of the delirium diagnosis. Significant predictors of mortality in fully adjusted models were older age, male gender, white (compared with non-white) ethnicity, and HoNOS subscales measuring physical ill-health and functional impairment. No mortality associations were found with cognitive function, dementia, or psychological symptoms. CONCLUSIONS: In people with delirium diagnosed by mental health services, mortality risk was high and predicted by demographic and physical health status rather than by cognitive function or psychological profile.

First things first: similar list length and output order effects for verbal and nonverbal stimuli.

When participants are presented with a short list of unrelated words and they are instructed that they may recall in any order, they nevertheless show a very strong tendency to recall in forward serial order. Thus, if asked to recall in any order: "hat, mouse, tea, stairs," participants often respond "hat, mouse, tea, stairs" even though there was no forward order requirement of the task. In 4 experiments, we examined whether this tendency is language-specific, reflecting mechanisms involved with speech perception, speech production, and/or verbal short-term memory. Specifically, we examined whether we would observe similar findings when participants were asked to recall, in any order, lists of between 1 and 15 nonverbal stimuli, such as visuospatial locations (Experiment 1, Experiment 3, Experiment 4), or touched facial locations (Experiment 2). Contrary to a language-specific explanation, we found corresponding tendencies (albeit somewhat reduced) in the immediate free recall of these nonverbal stimuli. We conclude that the tendency to initiate recall of a short sequence of items with the first item is a general property of memory, which may be augmented by verbal coding.