The mnemonic advantage of processing fitness-relevant information

Nairne, Thompson, and Pandeirada (2007) proposed that our memory systems serve an adaptive function and that they have evolved to help us remember fitness-relevant information. In a series of experiments, they demonstrated that processing words according to their survival relevance resulted in better retention than did rating them for pleasantness, personal relevance, or relevance to moving to a new house. The aim of the present study was to examine whether the advantage of survival processing could be replicated, using a control condition that was designed to match the survival processing task in arousal, novelty, and media exposure--the relevance to planning a bank heist. We found that survival processing nonetheless yielded better retention on both a recall (Experiment 1) and a recognition (Experiment 2) test. This mnemonic advantage of survival processing was also obtained when words were rated for their relevance to a character depicted in a video clip (Experiment 3). Our findings provide additional evidence that the mnemonic benefit of survival processing is a robust phenomenon, and they also support the utility of adopting a functional perspective in investigating memory.     

Striatal outcome processing in healthy aging

Functional MRI of young adults has implicated the striatum in the processing of rewarding and punishing events. To date, only two published experiments (Samanez-Larkin et al., 2007; Schott et al., 2007) have explored similar phenomena in older adults, with both studies emphasizing the anticipation of monetary outcomes. To better understand older participants’ striatal responses to delivered outcomes, we engaged 20 older adults and 13 younger adults in a card-guessing task that rewarded correct guesses with monetary gain and punished incorrect guesses with monetary loss. Overall, the older adults retained most of the typical features of the striatal response, so that activity in the caudate head showed reliable differentiation between rewards and punishments during the 6- to 9-sec postoutcome window. Comparison of the older and younger adults also pointed to some potential aging effects on outcome activity, including reductions in the magnitude and extent of striatal activation, and a trend for the older adults to show a decreased early punishment response. In sum, our data suggest that the signaling of outcome valence remains relatively stable into late adulthood, although more research is needed to understand some subtle changes that might occur across the life span.     

The mnemonic effects of recall on immediate retention

In three experiments, we investigated the mnemonic effects of an initial recall on later recall in an immediate memory setting. Recall is generally assumed to interfere with the recall of subsequent items (output interference), but previous experiments have failed to control for the confounding effects of time. In the experiments reported here, the passage of time was held constant on all trials; what varied was whether an additional item was recalled (or simply presented) during the retention interval. The results revealed clear evidence of recall's mnemonic effects, but output interference seemed strongest when the initial recall was of an item that followed the target item in the memory list. When participants initially recalled an item immediately preceding the target, target recall improved. This pattern of results places constraints on current models of immediate retention.     

Effects of aging and depression on mnemonic discrimination ability

Aging and depression have been found to be associated with poorer performance in mnemonic discrimination. In the current study, a two-response format mnemonic similarity test, Cognitive Drug Research MST, was used to compare these effects. Seventy-six participants were tested; with 52 participants in the young group, aged 18–35 years, and 24 participants in the elderly group, aged 55 years or older. Twenty-two young participants and 10 elderly participants met DSM-IV criteria for MDD or dysthymia. Age-related deficits were found for lure identification and speed of response. Differences in speed of responses to lure images were found for younger depressed participants, and depressive symptom severity was found to be negatively associated with lure identification accuracy in the elderly. These findings may be viewed as putative behavioral correlates of decreased pattern separation ability, which may be indicative of altered hippocampal neurogenesis in aging and depression.     

Congruity effects in the survival processing paradigm

Five experiments were conducted to investigate a proposal by Butler, Kang, and Roediger (2009) that congruity (or fit) between target items and processing tasks might contribute, at least partly, to the mnemonic advantages typically produced by survival processing. In their research, no significant survival advantages were found when words were preselected to be highly congruent or incongruent with a survival and control (robbery) scenario. Experiments 1a and 1b of the present report show that survival advantages, in fact, generalize across a wide set of selected target words; each participant received a unique set of words, sampled without replacement from a large pool, yet significant survival advantages remained. In Experiment 2, we found a significant survival advantage using words that had been preselected by Butler et al. to be highly unrelated (or irrelevant) to both the survival and control scenarios. Experiment 3 showed a significant survival advantage using word sets that had been preselected to be highly congruent with both scenarios. Finally, Experiment 4 mixed congruent and incongruent words in the same list, more closely replicating the design used by Butler et al., and a highly reliable main effect of survival processing was still obtained (although the survival advantage for the congruent words did not reach conventional levels of statistical significance). Our results suggest that the null effects of survival processing obtained by Butler et al. may not generalize beyond their particular experimental design.     

The effects of healthy aging on mental imagery as revealed by egocentric and allocentric mental spatial transformations

Previous studies suggest that mental rotation can be accomplished by using different mental spatial transformations. When adopting the allocentric transformation, individuals imagine the stimulus rotation referring to its intrinsic coordinate frame, while when adopting the egocentric transformation they rely on multisensory and sensory-motor mechanisms. However, how these mental transformations evolve during healthy aging has received little attention. Here we investigated how visual, multisensory, and sensory-motor components of mental imagery change with normal aging. Fifteen elderly and 15 young participants were asked to perform two different laterality tasks within either an allocentric or an egocentric frame of reference. Participants had to judge either the handedness of a visual hand (egocentric task) or the location of a marker placed on the left or right side of the same visual hand (allocentric task). Both left and right hands were presented at various angular departures to the left, the right, or to the center of the screen. When performing the egocentric task, elderly participants were less accurate and slower for biomechanically awkward hand postures (i.e., lateral hand orientations). Their performance also decreased when stimuli were presented laterally. The findings revealed that healthy aging is associated with a specific degradation of sensory-motor mechanisms necessary to accomplish complex effector-centered mental transformations. Moreover, failure to find a difference in judging left or right hand laterality suggests that aging does not necessarily impair non-dominant hand sensory-motor programs.     

The effect of aging on the memory enhancement of the survival judgment task

This study investigated whether or not aging affected the benefit of a survival judgment task. Sixteen young adults and 16 older adults participated in this experiment. In the survival task, participants were requested to judge whether a word was necessary or not in a survival situation. In the self‐referent judgment task, participants were requested to judge how easily the word brings to mind an important personal experience. Participants in each condition were presented 18 concrete nouns at 4‐s intervals. Our results showed that even though the survival judgment task enhanced the memory performance in both the young adults and the older adults, the young adults outperformed the older adults in the survival and self‐referent judgment tasks.     

Context processing and context maintenance in healthy aging and early stage dementia of the Alzheimer's type

Declines in the ability to process context information may represent a fundamental mechanism of age-related cognitive changes. Two components of context processing--activation/updating and maintenance--were examined in a sample of healthy younger and older adults, along with individuals suffering from early stage dementia of the Alzheimer's type (DAT). All older adult groups showed context activation/updating impairments, whereas context maintenance was only impaired in the oldest adults (age>75 years) and was further exacerbated in DAT individuals. The results suggest that context processing may be composed of functionally dissociable components and point to the utility of this construct in understanding the timecourse of cognitive decline in healthy and pathological aging.     

Spatial and temporal processing in healthy aging: implications for perceptions of driving skills

Sensitivity to the attributes of a stimulus (form or motion) and accuracy when detecting rapidly presented stimulus information were measured in older (N = 36) and younger (N = 37) groups. Before and after practice, the older group was significantly less sensitive to global motion (but not to form) and less accurate on a rapid sequencing task when detecting the individual elements presented in long but not short sequences. These effect sizes produced power for the different analyses that ranged between 0.5 and 1.00. The reduced sensitivity found among older individuals to temporal but not spatial stimuli, adds support to previous findings of a selective age-related deficit in temporal processing. Older women were significantly less sensitive than older men, younger men and younger women on the global motion task. Gender effects were evident when, in response to global motion stimuli, complex extraction and integration processes needed to be undertaken rapidly. Significant moderate correlations were found between age, global motion sensitivity and reports of perceptions of other vehicles and road signs when driving. These associations suggest that reduced motion sensitivity may produce functional difficulties for the older adults when judging speeds or estimating gaps in traffic while driving.     

The mnemonic effect of choice

Psychonomic Bulletin & Review - Making choices during encoding leads to superior memory compared with having the same choices made for you. Evidence also suggests that chosen items might be...     

Looking for long-term mnemonic effects on serial recall: the legacy of Simonides

We investigated three issues with respect to the long-term serial recall of adults. First, retention interval was manipulated to obtain uncontaminated measures of long-term serial recall. Second, we compared serial recall of concrete and abstract nouns to determine how these materials might interact with various learning strategies over time. Third, control group participants were asked to describe the learning strategies used, allowing a comparison of technical mnemonic techniques with the spontaneously generated strategies of adults. We found that the delayed recall performance of participants who spontaneously used organizational or imagery-based strategies was comparable to that of those instructed in the method of loci and pegword technique. Word concreteness did not interact with any other variable. These results are discussed with regard to their implications for serial learning in educational settings.     

The frontal hypothesis of cognitive aging: factor structure and age effects on four frontal tests among healthy individuals

With 101 healthy aging adult participants, the authors investigated whether executive functions are a unitary concept. The authors established the factor structure of the Wisconsin Card Sorting Test (WCST; E. A. Berg, 1948), the Stroop color and word test (C. J. Golden, 1978), verbal fluency using the Controlled Oral Word Association Test (COWAT; Benton, 1967), and the Digits Backwards subtest of the Wechsler Adult Intelligence Scale-Revised (WAIS-R; D. Wechsler, 1981). The authors also evaluated the extent to which age and other demographic variables predicted common underlying properties of these frontal tests. Results revealed an age-related decline in executive abilities differentially reflected by the selected tasks. These data suggest caution using the COWAT to evaluate executive abilities in older people. The authors interpret findings to support the unitary view of executive abilities and the executive decline proposed by the frontal hypothesis.     

The executive control of mnemonic activity

The present study focused on the executive monitoring of a rehearsal strategy by sixth (11 years 5 months), tenth (15 years 8 months), and twelfth (17 years 9 months) graders and adults (27 years 4 months). The results showed that all of the adults spontaneously adopted an “optimal” strategy and generalized it to a second task. However, none of the sixth graders and only two tenth and three twelfth graders did so. All of the school subjects subsequently trained to rehearse, maintained the strategy without prompting, and showed evidence of transfer. In comparison to adults, the trained subjects' generalized routines became more similar to the adults' as grade increased. This study supports the notion that efficient executive functioning includes the case where continued use of a mnemonic routine is a reasonable response to an objective change in an information-processing task.     

The mnemonic value of perceptual identification

In four experiments, subjects were required to name words presented on a CRT screen. On generate trials, the words were presented quickly, at a point where roughly half could be identified correctly; on read trials, the items were presented for a full second, allowing for rapid and easy naming. A surprise recognition test for the presented items then revealed a substantial retention advantage for the briefly presented items, but no similar advantage was produced in a recall. It is argued that under rapid viewing conditions subjects may fail to extract enough visual features to allow for immediate resolution, requiring the initiation of a kind of data-driven generation process. This latter process then produces a generation effect for the briefly presented items compared with the read items, but only on a retention test that shows sensitivity to data-driven processing. These results are discussed from the standpoint of current theoretical views on the generation effect.     

The effects of associations and aging on illusory recollection

Younger and older adults (mean years = 20.5 and 75) studied lists of associated words for a final recognition test. The length (5, 10, or 15 associates) and modality (auditory or visual) of study lists were manipulated within subjects. For both groups, increasing the number of associates increased illusory recollections of a related lure's presentation (measured by source judgments and the Memory Characteristics Questionnaire). This pattern suggests that associative activation of the lure influenced illusory recollection, and aging spared this process. In contrast, age impaired the recollection of source for studied words (auditory or visual) and had identical effects on source attributions for related lures. This pattern suggests that the true recollection of source influenced illusory recollection of source, and age impaired this process. To account for these and other results, we propose that associative activation drives an attribution process that binds subjectively detailed features to a false memory.     

The generalizability of training gains in dementia: effects of an imagery-based mnemonic on face-name retention duration

The generalizability of the results from a case study on the effects of an imagery mnemonic on face-name recall in dementia was examined (Hill, Evankovich, Sheikh, & Yesavage, 1987). Seven patients with Alzheimer's disease (AD) and 1 patient with multi-infarct dementia (MID) were trained by using the method devised by Hill et al. Application of the mnemonic increased the time during which face-name associations could be held in memory for 1 AD patient, and this improvement was maintained in a 1-month follow-up assessment. However, no training gains were observed for the remaining 7 patients, thus questioning the generalizability of this method in enhancing memory in dementia.     

The effects of aging on the working memory processes of multimodal information

Normal aging is associated with deficits in working memory processes. However, the majority of research has focused on storage or inhibitory processes using unimodal paradigms, without addressing their relationships using different sensory modalities. Hence, we pursued two objectives. First, was to examine the effects of aging on storage and inhibitory processes. Second, was to evaluate aging effects on multisensory integration of visual and auditory stimuli. To this end, young and older participants performed a multimodal task for visual and auditory pairs of stimuli with increasing memory load at encoding and interference during retention. Our results showed an age-related increased vulnerability to interrupting and distracting interference reflecting inhibitory deficits related to the off-line reactivation and on-line suppression of relevant and irrelevant information, respectively. Storage capacity was impaired with increasing task demands in both age groups. Additionally, older adults showed a deficit in multisensory integration, with poorer performance for new visual compared to new auditory information.     

The effects of location cuing on redundant-target processing

The present study is concerned with the redundany gain: the observation that subjects respond faster to simultaneously presented redundant targets than to single targets. This finding is usually interpreted as evidence for parallel, self-terminating, unlimited-capacity processing. Alternatively, it has been claimed that the reaction-time advantage with redundant targets is simply due to spatial uncertainty under single-target conditions. The present study tested this hypothesis. In Experiment 1, subjects responded when one, two, or three letters E were presented, and refrained from responding when one, two, or three letters F were presented. In half of the trials, location uncertainty was eliminated by presentation of a line segment at one of the locations of the subsequently appearing target letters. The results reject the alternative spatial-uncertainty explanation: even when the location of the impending target is cued in advance, there is no attenuation of the redundancy gain. Experiment 2 served as a control experiment and showed a clear redundancy gain, even in conditions in which it was ensured that, before display onset, attention was directed to a location of one of the impending targets.