Differential effects of age on item and associative measures of memory: a meta-analysis

In this meta-analysis, the authors evaluated recent suggestions that older adults' episodic memory impairments are partially due to a reduced ability to encode and retrieve associated/bound units of information. Results of 90 studies of episodic memory for both item and associative information in 3,197 young and 3,192 older adults provided support for the age-related associative/binding deficit suggestion, indicating a larger effect of age on memory for associative information than for item information. Moderators assessed included the type of associations, encoding instructions, materials, and test format. Results indicated an age-related associative deficit in memory for source, context, temporal order, spatial location, and item pairings, in both verbal and nonverbal material. An age-related associative deficit was quite pronounced under intentional learning instructions but was not clearly evident under incidental learning instructions. Finally, test format was also found to moderate the associative deficit, with older adults showing an associative/binding deficit when item memory was evaluated via recognition tests but not when item memory was evaluated via recall tests, in which case the age-related deficits were similar for item and associative information.     

Cross-modal and intra-modal binding between identity and location in spatial working memory: The identity of objects does not help recalling their locations

In this study we tested incidental feature-to-location binding in a spatial task, both in unimodal and cross-modal conditions. In Experiment 1 we administered a computerised version of the Corsi Block-Tapping Task (CBTT) in three different conditions: the first one analogous to the original CBTT test; the second one in which locations were associated with unfamiliar images; the third one in which locations were associated with non-verbal sounds. Results showed no effect on performance by the addition of identity information. In Experiment 2, locations on the screen were associated with pitched sounds in two different conditions: one in which different pitches were randomly associated with locations and the other in which pitches were assigned to match the vertical position of the CBTT squares congruently with their frequencies. In Experiment 2 we found marginal evidence of a pitch facilitation effect in the spatial memory task. We ran a third experiment to test the same conditions of Experiment 2 with a within-subject design. Results of Experiment 3 did not confirm the pitch–location facilitation effect. We concluded that the identity of objects does not affect recalling their locations. We discuss our results within the framework of the debate about the mechanisms of “what” and “where” feature binding in working memory.     

Incidental image memorability

ABSTRACT

Recent studies using intentional memory tasks showed that images differ consistently in memorability. Here, we used a surprise recognition memory test. We asked how incidental encoding would affect the consistency and ranking of the memorability scores. If memorability is truly an intrinsic property of the image, one should not expect large differences between incidental and intentional conditions. On the other hand, participants might process images differently when not anticipating a memory test, yielding different results. The study list of our incidental memory task was identical to our previous, intentional study. Participants were to watch the images of this list carefully as they appeared on the screen one by one (free viewing); supposedly for a study about eye movements. Afterwards, a surprise recognition memory test was administered. Despite the free viewing instructions during the study phase, the resulting incidental image memorability scores still showed high levels of consistency across participants. In addition, the overlap between the incidental and intentional memorability ranking was large. These results provide further support for the idea of memorability as an intrinsic image property and add to its ecological validity, as people rarely memorise images intentionally.     

Do you remember where sounds,pictures and words came from? The role of the stimulus format in object location memory

Contrasting results in visual and auditory spatial memory stimulate the debate over the role of sensory modality and attention in identity-to-location binding. We investigated the role of sensory modality in the incidental/deliberate encoding of the location of a sequence of items. In 4 separated blocks, 88 participants memorised sequences of environmental sounds, spoken words, pictures and written words, respectively. After memorisation, participants were asked to recognise old from new items in a new sequence of stimuli. They were also asked to indicate from which side of the screen (visual stimuli) or headphone channel (sounds) the old stimuli were presented in encoding. In the first block, participants were not aware of the spatial requirement while, in blocks 2, 3 and 4 they knew that their memory for item location was going to be tested. Results show significantly lower accuracy of object location memory for the auditory stimuli (environmental sounds and spoken words) than for images (pictures and written words). Awareness of spatial requirement did not influence localisation accuracy. We conclude that: (a) object location memory is more effective for visual objects; (b) object location is implicitly associated with item identity during encoding and (c) visual supremacy in spatial memory does not depend on the automaticity of object location binding.     

Print adverts: Not remembered but memorable

Attempts to measure advertising effectiveness have relied on explicit memory measures based on recall or recognition. However, recent cognitive research has shown that not only is it possible to measure unconscious effects of prior experience through implicit tests of memory, but that such performance is independent of explicit recollection. The present study sought to determine whether it is possible to demonstrate the same pattern of findings using print advertising in an ecologically valid situation. Eighty subjects saw 25 full-page colour magazine adverts in either a deliberate or incidental study condition and subsequently rated (on four salient dimensions) a set of 50 adverts, which included the target adverts. Following the ratings subjects were asked to indicate which of the adverts they recognized as having been in the original set. While the deliberate study group recognized around 60 per cent of the adverts, the incidental study group recognized only 11 per cent. However, both groups showed the same positive bias in attitudes towards the adverts they had been exposed to compared to the ones they had not seen before. Thus, in line with by the cognitive literature, it is possible to show shifts in attitudes that are independent of conscious recollection. This data questions advertisers' reliance one explicit memory tests as measures of advertising effectiveness.     

Measures of fluency as predictors of incidental memory among older adults

This study investigated fluency performance as a mediator of age-related declines in incidental memory performance as both are thought to rely on strategic retrieval processes. A large sample of community dwelling older adults completed a battery of tests assessing fluency, verbal knowledge, speed of information processing, and incidental recall. Fluency measures included initial and excluded letter fluency and the Uses for Objects Test, and they were assumed to reflect increasing reliance on strategic retrieval search. Speed emerged as the best mediator of age-related variance in incidental recall, and Uses for Objects Test performance added to the variance after controlling for verbal knowledge and speed. The results suggest that age-related decline in incidental recall is largely due to speed and the strategic search of memory.     

A Sex Difference on a Novel Spatial Working Memory Task in Humans

Neurophysiological and behavioral evidence suggests that the prefrontal cortex (PFC) may be sexually differentiated in nonhuman primates. The present study examined whether there are sex differences in working memory in humans that might reflect sexual differentiation of human PFC. Male and female undergraduates were administered a novel multitrial spatial working memory task (SPWM) and a verbal working memory task. In three experiments, females committed significantly fewer working memory errors and took significantly less time to reach criterion than males on the SPWM task. The female advantage was not accounted for by differences in general intellectual ability, attention, perceptual speed, incidental memory, or speed of verbal access. In Study 3, a sex difference was also observed on a measure of verbal working memory. The findings suggest that some prefrontal functions may be sexually differentiated in humans.     

The organisation of spatial and temporal relations in memory

Episodic memories are comprised of details of “where” and “when”; spatial and temporal relations, respectively. However, evidence from behavioural, neuropsychological, and neuroimaging studies has provided mixed interpretations about how memories for spatial and temporal relations are organised—they may be hierarchical, fully interactive, or independent. In the current study, we examined the interaction of memory for spatial and temporal relations. Using explicit reports and eye-tracking, we assessed younger and older adults’ memory for spatial and temporal relations of objects that were presented singly across time in unique spatial locations. Explicit change detection of spatial relations was affected by a change in temporal relations, but explicit change detection of temporal relations was not affected by a change in spatial relations. Younger and older adults showed eye movement evidence of incidental memory for temporal relations, but only younger adults showed eye movement evidence of incidental memory for spatial relations. Together, these findings point towards a hierarchical organisation of relational memory. The implications of these findings are discussed in the context of the neural mechanisms that may support such a hierarchical organisation of memory.     

On the coding of spatial information

Two experiments studied recall of objects and their locations in an intentional-incidental learning paradigm. When studying spatial information, the usual incidental condition is not truly incidental, because subjects often deliberately use locations to help organize objects for recall. Therefore, a true incidental task was devised in which neither objects nor locations were expected to be recalled and for which explicit encoding of locations was irrelevant. There was only a small loss in recall of objects or their locations in a true incidental condition. It was concluded that a great deal of location information is automatically coded into long-term memory storage in the sense that active processing is not required. The data were contrasted with incidental processing of other attributes, such as color. Although adults performed better than children, there were no age-related interactions, indicating similarity of functioning at all ages studied.     

Is memory for spatial location automatically encoded?

Naveh-Benjamin (1987, 1988) has shown that memory for spatial location does not meet the criteria for automatic encoding as claimed by Hasher and Zacks (1979). Age, intention, concurrent processing demands, practice, strategies, and individual differences affected memory for location. These variables should have affected effortful but not automatic processing. The experiments reported in the present paper, in which a different task was used, showed that intention, practice, and concurrent processing demands did not affect memory for location. I concluded that (1) the location task used by Naveh-Benjamin included effortful subtasks and also incidental cover or concurrent processing tasks that interfered directly with performance, and (2) the variables that he manipulated may not have affected the encoding of location. The need to differentiate processes from task performance in analyzing the automaticity issue is discussed. The dominant mode for remembering location is automatic, but such information may also be remembered voluntarily.     

Long-term continuous, but not daily, environmental enrichment reduces spatial memory decline in aged male mice

Although environmental enrichment improves spatial memory and alters synaptic plasticity in aged rodents, it is unclear whether all types of enrichment treatments yield similar benefits. The present study examined the effects in aged male mice of three types of enrichment on spatial memory in Morris water maze and radial arm maze tasks, and on levels of the presynaptic protein synaptophysin in several brain regions. Non-enriched young and aged males were compared with males exposed to one of the following treatments for 10 weeks: 5 min of daily handling, 3 h of daily basic enrichment, or 24 h of continuous complex enrichment. Young controls outperformed aged controls in both tasks. Neither daily handling nor daily enrichment affected spatial memory or synaptophysin levels. In contrast, continuous enrichment significantly reduced age-related spatial memory decline in both tasks, such that this group was statistically indistinguishable from young controls in most measures of performance. Continuously enriched mice were also significantly better than other aged mice in several spatial memory measures. Despite these improvements, synaptophysin levels in the continuous enrichment group were significantly lower than those of young and aged controls in the frontoparietal cortex, hippocampus, and striatum, suggesting a negative relationship between synaptophysin levels and spatial memory in aged males. These data demonstrate that different types of enrichment in aged male mice have disparate effects on spatial memory, and that the relationship between enrichment-induced changes in synaptophysin levels and spatial memory in aged males differs from that we have previously reported in aged female mice.     

The effect of self-referencing on memory for different kinds of source information

ABSTRACT

Self-referential processing has been proven to be effective in improving source memory. However, it is unclear whether different types of source information would be consistently enhanced when an item is self-referentially processed. In two experiments, the authors examined the influence of the self (compared with other-referencing and semantic processing) as well as learning intention (incidental/intentional learning) on memory for two types of source information (spatial location and colour) that differ in the amount of cognitive resources they require to be encoded in memory. Results show that self-referencing has enhanced memory for spatial location of words whatever this information is learned intentionally or incidentally, whereas it cannot facilitate memory for the colour of words under the intentional learning condition, nor can it under the incidental condition. These findings suggest that self-referential processing is beneficial in memory improvement but not all-powerful, a source self-reference effect is subject to source information type.     

Age-related differences on a new test of temporal order memory for everyday events

We developed a new test to examine incidental temporal order memory for a self-generated sequence of tasks one might complete in everyday life. Young and older adults were given 10 cards, each listing a task one might accomplish in a typical day. Participants were asked to self-generate a “to do” list by placing the 10 cards in a sequence representing the order in which they would accomplish the tasks, but were not informed of a subsequent memory test. We assessed immediate free recall, delayed free recall, and delayed cued recall for the order of the tasks in the sequence. Older adults were significantly impaired relative to young adults on immediate free recall, delayed free recall, and delayed cued recall. Correlation analyses with standardized neuropsychological tests provide preliminary evidence for construct validity for our test, which is portable and can be rapidly administered in clinical or laboratory settings.     

Do pulmonary function and smoking behavior predict cognitive function? findings from a british sample

Abstract

The relationship of smoking behavior, pulmonary function, and four measures of cognitive function was studied in a sample of 4,399 men and women (mean age = 44.7 f 17.1 years; age range: 18 to 94 years) randomly selected from British electoral registers. Each subject was assessed with a face-to-face structured interview (including demographic data, smoking history, and health-related questions) as well as cognitive testing [simple reaction time (SRT), choice reaction time (CRT), incidental memory, and spatial reasoning] and pulmonary function testing. Results indicated that smoking was associated with somewhat better performance on the CRT and memory tasks, and that smoking behavior was not associated with decrements in cognitive performance. Impaired pulmonary function was generally associated with poorer cognitive performance on all of the cognitive measures, suggesting that pulmonary function may be a relevant factor to consider in experimental studies of smoking and cognitive function among healthy adults.     

Different types of working memory binding in epilepsy patients with unilateral anterior temporal lobectomy

The medial temporal lobe is an important structure for long-term memory formation, but its role in working memory is less clear. Recent studies have shown hippocampal involvement during working memory tasks requiring binding of information. It is yet unclear whether this is limited to tasks containing spatial features. The present study contrasted three binding conditions and one single-item condition in patients with unilateral anterior temporal lobectomy.A group of 43 patients with temporal lobectomy (23 left; 20 right) and 20 matched controls were examined with a working memory task assessing spatial relational binding (object–location), non-spatial relational binding (object–object), conjunctive binding (object–colour) and working memory for single items. We varied the delay period (3 or 6 s), as there is evidence showing that delay length may modulate working memory performance.The results indicate that performance was worse for patients than for controls in both relational binding conditions, whereas patients were unimpaired in conjunctive binding. Single-item memory was found to be marginally impaired, due to a deficit on long-delay trials only.In conclusion, working memory binding deficits are found in patients with unilateral anterior temporal lobectomy. The role of the medial temporal lobe in working memory is not limited to tasks containing spatial features. Rather, it seems to be involved in relational binding, but not in conjunctive binding. The medial temporal lobe gets involved when working memory capacity does not suffice, for example when relations have to be maintained or when the delay period is long.     

Is verbal–spatial binding in working memory impaired by a concurrent memory load?

Binding processes play a critical role in memory. We investigated whether the binding of (visually presented) verbal and spatial (locations) information involves general attentional resources, as stipulated in the revised working memory model, by comparing measures of binding in the presence and absence of a concurrent memory load. Using an adaptation of a probe recognition task contrasting performance between intact and recombined conditions, we found that the concurrent retention of a sequence of three pure tones eliminated verbal–spatial binding. The present study constitutes the first to directly measure the impact of a concurrent memory load on verbal–spatial binding and suggests that such binding may indeed recruit attentional resources, consistent with some recent findings in the visual–spatial binding literature.     

Learning in repeated visual search

Visual search (e.g., finding a specific object in an array of other objects) is performed most effectively when people are able to ignore distracting nontargets. In repeated search, however, incidental learning of object identities may facilitate performance. In three experiments, with over 1,100 participants, we examined the extent to which search could be facilitated by object memory and by memory for spatial layouts. Participants searched for new targets (real-world, nameable objects) embedded among repeated distractors. To make the task more challenging, some participants performed search for multiple targets, increasing demands on visual working memory (WM). Following search, memory for search distractors was assessed using a surprise two-alternative forced choice recognition memory test with semantically matched foils. Search performance was facilitated by distractor object learning and by spatial memory; it was most robust when object identity was consistently tied to spatial locations and weakest (or absent) when object identities were inconsistent across trials. Incidental memory for distractors was better among participants who searched under high WM load, relative to low WM load. These results were observed when visual search included exhaustive-search trials (Experiment 1) or when all trials were self-terminating (Experiment 2). In Experiment 3, stimulus exposure was equated across WM load groups by presenting objects in a single-object stream; recognition accuracy was similar to that in Experiments 1 and 2. Together, the results suggest that people incidentally generate memory for nontarget objects encountered during search and that such memory can facilitate search performance.     

Episodic memory for object location versus episodic memory for object identity: do they rely on distinct encoding processes?

Three experiments were conducted to determine whether encoding processes that support episodic memory for object location are distinct from those that support memory for object identity. Guided by transfer-appropriate processing notions, we examined with an incidental learning paradigm whether an attentional focus on object location at encoding promotes subsequent recovery of object location, whereas a focus on object identity promotes recovery of object identity. We found that judging spatial relationships at encoding selectively supports recovery of object location, provided the test assesses memory for these relationships (rather than absolute location); our results also showed that judging physical and semantic object attributes promotes recovery of object identity preferentially. Contrasting with these domain-specific effects was evidence that identification processes involved in object naming boost memory for object identity as well as for absolute object location. Object identification at encoding may support memory performance in both domains by triggering the binding of identity and location information through a mechanism of object-based attentional selection.     

Influence of affective meaning on memory for contextual information

In 4 experiments, the authors investigated the influence of the affective meaning of words on memory for 2 kinds of contextual features that differ in the amount of effortful processes they require to be encoded in memory (i.e., color and spatial location). The main results showed that memory for color, in which words were typed, was better for emotional than for neutral words, but only when color information was learned incidentally. In contrast, spatial location of the words was better remembered for emotional than for neutral words whatever the encoding conditions (intentional vs. incidental). It is suggested that the influence of affective meaning on context memory may involve an automatic attraction of attention to contextual features associated with emotional words.