Causal chunking: memory and inference in ongoing interaction

We propose that people simplify their perceptions of their interactions by organizing them into discrete casual chunks. Once formed, these chunks presumably influence the extent to which people are aware of their influence on others, as well as their impressions of others. We anticipated that people would form self-causal chunks (e.g., my action causes my partner's action) when they possessed an offensive set and other-causal chunks when they possessed a defensive set. We also expected that a self-causal chunking strategy would make salient people's influence on their partners and thereby discourage them from concluding that their partner's behaviors reflected underlying dispositions. In contrast, we anticipated that an other-causal chunking strategy would obscure people's influence on their partners, thereby encouraging them to infer that their partners' behaviors reflected underlying dispositions. We tested these hypotheses by inducing participants to develop either a defensive or an offensive set prior to interacting with another person in a simulated arms race. After the interactions, we assessed the manner in which participants chunked their interactions, as well as their impressions of partners. The results supported our predictions. The implications of these findings for understanding conflict and misunderstanding in interpersonal relations are discussed.     

Hierarchical coding in the perception and memory of spatial layouts

Two experiments were performed to investigate the organization of spatial information in perception and memory. Participants were confronted with map-like configurations of objects which were grouped by color (Experiment 1) or shape (Experiment 2) so as to induce cognitive clustering. Two tasks were administered: speeded verification of spatial relations between objects and unspeeded estimation of the Euclidean distance between object pairs. In both experiments, verification times, but not distance estimations, were affected by group membership. Spatial relations of objects belonging to the same color or shape group were verified faster than those of objects from different groups, even if the spatial distance was identical. These results did not depend on whether judgments were based on perceptually available or memorized information, suggesting that perceptual, not memory processes were responsible for the formation of cognitive clusters. Received: 7 October 1999 / Accepted: 17 February 2000     

Water can induce better spatial memory performance than food in radial maze learning by rats1

Abstract: Two experiments were carried out to test the differential effects of hunger and thirst on memory performance. In Experiment 1, two groups of rats were exposed to an original radial‐maze task and then to a 30‐min retention‐memory task. The food‐deprived group completed the original task more quickly than the water‐deprived group, but the thirsty group mastered the memory task more quickly than the hungry group (p < 0.01). In Experiment 2, deprivation conditions were changed from the original to the memory task. The food‐water group completed the memory task more rapidly than the water‐food group (p < 0.05). Thirst proved to constitute a more favorable condition for retention‐memory learning. The applicability of several theories is discussed.     

Hierarchical encoding in visual working memory: ensemble statistics bias memory for individual items

Influential models of visual working memory treat each item to be stored as an independent unit and assume that there are no interactions between items. However, real-world displays have structure that provides higher-order constraints on the items to be remembered. Even in the case of a display of simple colored circles, observers can compute statistics, such as mean circle size, to obtain an overall summary of the display. We examined the influence of such an ensemble statistic on visual working memory. We report evidence that the remembered size of each individual item in a display is biased toward the mean size of the set of items in the same color and the mean size of all items in the display. This suggests that visual working memory is constructive, encoding displays at multiple levels of abstraction and integrating across these levels, rather than maintaining a veridical representation of each item independently.     

NT-3 facilitates hippocampal plasticity and learning and memory by regulating neurogenesis

In the adult brain, the expression of NT-3 is largely confined to the hippocampal dentate gyrus (DG), an area exhibiting significant neurogenesis. Using a conditional mutant line in which the NT-3 gene is deleted in the brain, we investigated the role of NT-3 in adult neurogenesis, hippocampal plasticity, and memory. Bromodeoxyuridine (BrdU)-labeling experiments demonstrated that differentiation, rather than proliferation, of the neuronal precursor cells (NPCs) was significantly impaired in DG lacking NT-3. Triple labeling for BrdU, the neuronal marker NeuN, and the glial marker GFAP indicated that NT-3 affects the number of newly differentiated neurons, but not glia, in DG. Field recordings revealed a selective impairment in long-term potentiation (LTP) in the lateral, but not medial perforant path-granule neuron synapses. In parallel, the NT-3 mutant mice exhibited deficits in spatial memory tasks. In addition to identifying a novel role for NT-3 in adult NPC differentiation in vivo, our study provides a potential link between neurogenesis, dentate LTP, and spatial memory.     

Autobiographical memory for spatial location is unaffected by delay

To examine recall of personal spatial location during a previously experienced event, Lafayette College students located themselves in a version of their incoming class photograph that was all black with each individual figure identified in white. They then subsequently identified themselves in the original version of the photograph. The distance between the initial choice in the obscured version and the individual's correct location was recorded. Participants were remarkably and equally accurate in identifying their location irrespective of whether the event occurred 2, 6, 18, 30, 38, or 42 months earlier. Although non-spatial aspects of the cue and rehearsal did not influence accuracy, objective location in the photograph partially accounted for error rates. However, none of these factors was sufficient to explain the absence of delay effects. Unlike spatial memory, recall of temporal information showed a linear decrease in accuracy with delay, but with exceptionally accurate performance by senior-class students.     

Bias in spatial memory: a categorical endorsement

Two experiments investigated how angular estimates reflect bias as a function of response mode, geometric plane of variation, number of implicit categories, memory load and intervening task conditions. In Experiment 1, participants made motor and verbal estimates of incline and azimuth from memory. Estimates in both response modes showed signs of bias predicted by a single-category adaptation of Huttenlocher et al. [Huttenlocher, J., Hedges, L. V., & Duncan, S. (1991). Categories and particulars: Prototype effects in estimating spatial location. Psychological Review, 98, 352-376] category-adjustment model. In Experiment 2, participants made motor estimates of azimuth from memory under a variety of conditions. Stimuli in this experiment were distributed along two contiguous spatial categories. Although increasing levels of cognitive load did not produce a graded effect, participants' estimates were biased and were well described by a multiple-category adaptation of the category-adjustment model. Results from both studies supported an implicit region-based model of bias in spatial memory. These findings were discussed with respect to accounts of spatial memory that propose multiple systems or formats for coding.     

Reinforcement of inhibitory positional priming by spatial working memory contents

This study examined whether positional priming of pop-out is modulated by spatial working memory (WM). In Experiments 1A and 1B, observers were presented with a to-be-memorized item (Experiment 1A: triangle; Experiment 1B: circle) prior to performing a block of search trials, with triangular stimulus configurations (one target, two distractors) on an underlying elliptical frame. Each search block was followed by a memory test (i.e., memory conditions). In Experiment 1C, the presentation of the memory item (triangle) was immediately followed by the memory test, and the search block was performed after this test (i.e., no-memory condition). It was found that targets presented at a previous target were detected faster and targets presented at a previous distractor location slower, relative to a previous empty (‘neutral’) stimulus location, respectively. While facilitatory position priming was uninfluenced by the memory manipulation, inhibitory positional priming was larger in the memory than no-memory condition, but only when the memory stimulus (triangle) matched the (triangle) configuration formed by the three search items. This finding of larger inhibitory priming under memory conditions provides further evidence that positional priming, rather than being purely bottom-up determined, is open to top-down influences.     

The selective disruption of spatial working memory by eye movements

In the late 1970s/early 1980s, Baddeley and colleagues conducted a series of experiments investigating the role of eye movements in visual working memory. Although only described briefly in a book (Baddeley, 1986), these studies have influenced a remarkable number of empirical and theoretical developments in fields ranging from experimental psychology to human neuropsychology to nonhuman primate electrophysiology. This paper presents, in full detail, three critical studies from this series, together with a recently performed study that includes a level of eye movement measurement and control that was not available for the older studies. Together, the results demonstrate several facts about the sensitivity of visuospatial working memory to eye movements. First, it is eye movement control, not movement per se, that produces the disruptive effects. Second, these effects are limited to working memory for locations and do not generalize to visual working memory for shapes. Third, they can be isolated to the storage/maintenance components of working memory (e.g., to the delay period of the delayed-recognition task). These facts have important implications for models of visual working memory.     

The selective disruption of spatial working memory by eye movements

In the late 1970s/early 1980s, Baddeley and colleagues conducted a series of experiments investigating the role of eye movements in visual working memory. Although only described briefly in a book (Baddeley, 1986 Baddeley AD 1986 Working memory London Oxford University Press  [Google Scholar]), these studies have influenced a remarkable number of empirical and theoretical developments in fields ranging from experimental psychology to human neuropsychology to nonhuman primate electrophysiology. This paper presents, in full detail, three critical studies from this series, together with a recently performed study that includes a level of eye movement measurement and control that was not available for the older studies. Together, the results demonstrate several facts about the sensitivity of visuospatial working memory to eye movements. First, it is eye movement control, not movement per se, that produces the disruptive effects. Second, these effects are limited to working memory for locations and do not generalize to visual working memory for shapes. Third, they can be isolated to the storage/maintenance components of working memory (e.g., to the delay period of the delayed-recognition task). These facts have important implications for models of visual working memory.     

Configural representations in spatial working memory: modulation by perceptual segregation and voluntary attention

In what form are multiple spatial locations represented in working memory? The present study revealed that people often maintain the configural properties (interitem relationships) of visuospatial stimuli even when this information is explicitly task-irrelevant. However, the results also indicated that the voluntary allocation of selective attention prior to stimulus presentation, as well as feature-based perceptual segregation of relevant from irrelevant stimuli, can eliminate the influence of stimulus configuration on location-change detection performance. In contrast, voluntary attention cued to the relevant target location following presentation of the stimulus array failed to attenuate these influences. Thus, whereas voluntary selective attention can isolate or prevent the encoding of irrelevant stimulus locations and configural properties, people, perhaps due to limitations in attentional resources, reliably fail to isolate or suppress configural representations that have been encoded into working memory.     

Support for a bimodal role for type II adrenal steroid receptors in spatial memory.

We investigated the effects of acute adrenal steroid treatment on spatial memory using the Y-maze and employing adrenal steroid receptor antagonists and agonists. For receptor activation, adrenalectomized rats were injected 2 h prior to their first Y-maze trial with sesame oil (adrenalectomy or SHAM), stress levels of corticosterone, a Type I receptor agonist (aldosterone), or a Type II receptor agonist (RU362). For receptor inactivation, unoperated rats were injected with a Type I receptor antagonist (RU318), a Type II receptor antagonist (RU555), sesame oil, or not injected at all. The findings indicated that spatial memory was impaired when the Type II receptors were blocked (RU555) or highly occupied (corticosterone or RU362) and normal for the other treatment conditions. These data suggest that the Type II receptors may be responsible for the inverted U-shaped relationship between spatial memory and corticosterone levels reported by others.     

Interference effects by spatial proximity and age-related declines in spatial memory by Japanese monkeys (Macaca fuscata): deficits in the combined use of multiple spatial cues

Spatial information processing was assessed in 3 young (4-10 years old) and 4 aged (24-25 years old) Japanese monkeys (Macaca fuscata) on 3 delayed nonmatching-to-position (DNMP) tests with relatively short delays of 5 s. Each test had 3 conditions of different horizontal distances between sample and to-be-nonmatched positions. Experiment 1 demonstrated that the performance on the DNMP test in both age groups was impaired when 2 stimulus positions were located next to each other; however, it was fairly accurate when they were located farther apart, suggesting that interference is introduced by spatial proximity. Experiment 2 revealed age-related differences in the situation in which an additional spatial cue, depth information, was available by extending the stimulus array of the DNMP test to a 4 x 2 matrix. In this test, young monkeys performed accurately irrespective of position distance between stimuli, whereas the aged monkeys' performance remained the same as before. Experiment 3 confirmed that the recognition ability in aged monkeys was well preserved on DNMP tests with different objects. These patterns of results indicate that the ability to use information from multiple spatial cues is not accessible to the aged monkeys.     

The floor effect: Impoverished spatial memory for elevator buttons

People typically remember objects to which they have frequently been exposed, suggesting that memory is a by-product of perception. However, prior research has shown that people have exceptionally poor memory for the features of some objects (e.g., coins) to which they have been exposed over the course of many years. Here, we examined how people remember the spatial layout of the buttons on a frequently used elevator panel, to determine whether physical interaction (rather than simple exposure) would ensure the incidental encoding of spatial information. Participants who worked in an eight-story office building displayed very poor recall for the elevator panel but above-chance performance on a recognition test. Performance was related to how often and how recently the person had used the elevator. In contrast to their poor memory for the spatial layout of the elevator buttons, most people readily recalled small distinctive graffiti on the elevator walls. In a more implicit test, the majority were able to locate their office floor and the eighth floor button when asked to point toward these buttons when in the actual elevator, with the button labels covered. However, identification was very poor for other floors (including the first floor), suggesting that even frequent interaction with information does not always lead to accurate spatial memory. These findings have implications for understanding the complex relationships among attention, expertise, and memory.     

Well, slap my thigh: expression of surprise facilitates memory of surprising material

Two studies examined the general prediction that one's emotional expression should facilitate memory for material that matches the expression. The authors focused on specific facial expressions of surprise. In the first study, participants who were mimicking a surprised expression showed better recall for the surprising words and worse recall for neutral words, relative to those who were mimicking a neutral expression. Study 2 replicated the results of Study 1, showing that participants who mimicked a surprised expression recalled more words spoken in a surprising manner compared with those that sounded neutral or sad. Conversely, participants who mimicked sad facial expressions showed greater recall for sad than neutral or surprising words. The results provide evidence of the importance of matching the emotional valence of the recall content to the facial expression of the recaller during the memorization period. (PsycINFO Database Record (c) 2008 APA, all rights reserved).     

Reconstructing the recent visual past: Hierarchical knowledge-based effects in visual working memory

This paper presents two experiments that examine the influence of multiple levels of knowledge on visual working memory (VWM). Experiment 1 focused on memory for faces. Faces were selected from continua that were constructed by morphing two face photographs in 100 steps; half of the continua morphed a famous face into an unfamiliar one, while the other half used two unfamiliar faces. Participants studied six sequentially presented faces each from a different continuum, and at test they had to locate one of these within its continuum. Experiment 2 examined immediate memory for object sizes. On each trial, six images were shown; these were either all vegetables or all random shapes. Immediately after each list, one item was presented again, in a new random size, and participants reproduced its studied size. Results suggested that two levels of knowledge influenced VWM. First, there was an overall central-tendency bias whereby items were remembered as being closer to the overall average or central tokens (averaged across items and trials) than they actually were. Second, when object knowledge was available for the to-be-remembered items (i.e., famous face or typical size of a vegetable) a further bias was introduced in responses. The results extend the findings of Hemmer and Steyvers (Psychonomic Bulletin & Review, 16, 80–87, 2009a) from episodic memory to VWM and contribute to the growing literature which illustrates the complexity and flexibility of the representations subtending VWM performance (e.g., Bae, Olkkonen, Allred, & Flombaum, Journal of Experimental Psychology: General, 144(4):744–63, 2015).     

Remaking memories: reconsolidation updates positively motivated spatial memory in rats

There is strong evidence that reactivation of a memory returns it to a labile state, initiating a restabilization process termed reconsolidation, which allows for updating of the memory. In this study we investigated reactivation-dependent updating using a new positively motivated spatial task in rodents that was designed specifically to model a human list-learning paradigm. On Day 1, rats were trained to run to three feeders (List 1) for rewards. On Day 2, rats were trained to run to three different feeders (List 2) in either the same (Reminder condition) or a different (No Reminder condition) experimental context than on Day 1. On Day 3, rats were cued to recall List 1. Rats in the Reminder condition made significantly more visits to List 2 feeders (intrusions) during List 1 recall than rats in the No Reminder condition, indicating that the reminder triggered reactivation and allowed integration of List 2 items into List 1. This reminder effect was selective for the reactivated List 1 memory, as no intrusions occurred when List 2 was recalled on Day 3. No intrusions occurred when retrieval took place in a different context from the one used at encoding, indicating that the expression of the updated memory is dependent upon the retrieval context. Finally, the level of intrusions was highest when retrieval took place immediately after List 2 learning, and generally declined when retrieval occurred 1-4 h later, indicating that the List 2 memory competed with short-term retrieval of List 1. These results demonstrate the dynamic nature of memory over time and the impact of environmental context at different stages of memory processing.     

Temporal-spatial memory: retrieval of spatial information does not reduce recency

Factors influencing the shape of serial position curves in non-verbal serial short-term memory were examined, using a task testing memory for the position of dots. Similar recency slopes were found when both position and order were recalled (Experiment 1A) and when order only was required (Experiment 1B). This observation was confirmed and tested further in conditions requiring the same encoding but different amounts of spatial information at retrieval (Experiment 2). However, Experiment 2 also revealed an effect of spatial information retrieval on the overall level of memory for recency items. Overall, the results indicate that spatial items produce bow-shaped serial positions curves in tasks requiring the maintenance of order information and that recency is affected by the demand on spatial information retrieval in terms of the overall level of performance but not in terms of the recency slope. These findings are contrary to what is found in the literature on serial verbal recall when both item and order information are required.     

Age,context, and spatial memory: A neuropsychological approach

Abstract

The hypothesis that a reduction in age differences in spatial location memory in the presence of distinctive cues reflects a decreased dependence on a hippocampally based memory system was tested in three experiments. In Experiments 1 and 2 the presence of distinctive cues did not reduce age differences in spatial location memory nor did these cues eliminate the significant relation between spatial location memory and a measure of hippocampal function. Distinctive cues did, however, place additional demands on processing resources and spatial visualization abilities. In Experiment 3 the relevance of prior knowledge was manipulated. With irrelevant prior knowledge there was a strong unique association between the hippocampal measure and outcome measure. With relevant prior knowledge there was no such association. the implications of these findings for understanding the role of the hippocampus in age-related decline in memory for locations are discussed.