The Attentional Boost Effect in Older Adults: Examining the Vulnerable Boost Hypothesis.

INTRODUCTION: The Attentional Boost Effect (ABE) occurs whenever participants recognize stimuli paired earlier with to-be-responded targets better than stimuli earlier paired with to-be-ignored distractors or presented on their own (baseline). Previous studies showed that the ABE does not occur in older adults when the encoding time is too short (500 ms/word) or when encoding is incidental, likely due to aging-related reductions in cognitive resources or limitations of processing speed. METHOD: In the present study, younger and older adults encoded words presented for 1000 ms under intentional instructions. In addition, to determine the potential impact of the retention interval, the recognition task was performed after a delay of 2 minutes (Experiment 1) or 20 minutes (Experiment 2). RESULTS: Under these conditions, older adults showed a significant ABE and the size of the effect was comparable to that achieved by younger adults. The magnitude of the ABE was vulnerable to the passage of time because the recognition advantage of target-paired words decreased sharply from 2 to 20 minutes. CONCLUSIONS: Taken together, our data demonstrate that younger and older adults may have comparable ABE effects under specific conditions and are similarly sensitive to interference.

Can divided attention at retrieval improve memory? Effects of target detection during recognition.

The attentional boost effect (ABE) is an improvement of memory under divided attention conditions in which stimulus encoding is enhanced when a target is detected in a simultaneous target-monitoring distracting task. Here we asked whether memory is similarly improved when the target-monitoring task occurs at the time of retrieval. In four experiments, participants encoded words under full attention then completed a recognition test under either divided attention, during which participants made recognition judgments while performing the target-monitoring task, or full attention, in which the target-monitoring task was not performed. Relative to distractor rejection, target detection increased hits and false alarms under divided attention with no net effect on discrimination. Targets and distractors had no effect on recognition under full attention. The target-related increase in hits and false alarms occurred regardless of whether the target-monitoring material matched or mismatched the test material and regardless of the target-to-distractor ratio and the target response. A change in bias accounts for the phenomenon, in which participants adopt a more lenient criterion for target-paired words than for distractor-paired words. The same divided attention manipulation that enhances memory at encoding does not similarly enhance memory at retrieval. Theoretical explanations are discussed.

The attentional boost effect for words in young and older adults.

The attentional boost effect (ABE) refers to enhanced memory for information that is learned under conditions of divided attention in which participants encode stimuli while performing a second task involving target monitoring. The present investigation examined the ABE in young and young-old adults in forced-choice recognition (Experiment 1), and in young, young-old, and older-old adults in yes/no recognition that included manipulations of word frequency and study-to-test changes in modality (Experiments 2 and 3). Contrary to previous findings that showed an elimination of the ABE in young-old adults (Bechi Gabrelli, Spataro, Pezzuti, & Rossi-Arnaud, 2018), young-old adults exhibited an ABE whose magnitude did not differ from that of young adults. Older-old adults, however, displayed a reduced ABE compared with the young. The results may be understood by a framework in which age-related cognitive declines create vulnerable boosted memories in the ABE that are more easily disrupted over time than the boosted memories in young adults. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Effects of Divided Attention at Retrieval on Conceptual Implicit Memory.

This study investigated whether conceptual implicit memory is sensitive to process-specific interference at the time of retrieval. Participants performed the implicit memory test of category exemplar generation (CEG; Experiments 1 and 3), or the matched explicit memory test of category-cued recall (Experiment 2), both of which are conceptually driven memory tasks, under one of two divided attention (DA) conditions in which participants simultaneously performed a distracting task. The distracting task was either syllable judgments (dissimilar processes), or semantic judgments (similar processes) on unrelated words. Compared to full attention (FA) in which no distracting task was performed, DA had no effect on CEG priming overall, but reduced category-cued recall similarly regardless of distractor task. Analyses of distractor task performance also revealed differences between implicit and explicit memory retrieval. The evidence suggests that, whereas explicit memory retrieval requires attentional resources and is disrupted by semantic and phonological distracting tasks, conceptual implicit memory is automatic and unaffected even when distractor and memory tasks involve similar processes.

Adult age differences in memory for schema-consistent and schema-inconsistent objects in a real-world setting.

The present study examined age-related differences in the inconsistency effect, in which memory is enhanced for schema-inconsistent information compared to schema-consistent information. Young and older adults studied schema-consistent and schema-inconsistent objects in an academic office under either intentional or incidental encoding instructions, and were given two recognition tests either immediately or after 48 hr: A yes/no item recognition test that included modified remember/know judgments and a token recognition test that required determining whether an original object was replaced with a different object with the same name. Young and older adults showed equivalent inconsistency effects in both item and token recognition tests, although older adults reported phenomenologically less rich memories of schema-inconsistent objects relative to young adults. These findings run counter to previous reports suggesting that aging is associated with processing declines at encoding that impair memory for details of schema-inconsistent or distinctive events. The results are consistent with a retrieval-based account in which age-related difficulties in retrieving contextual details can be offset by environmental support.

Attention and repetition priming in the verb generation task.

Transfer-appropriate processing (TAP) and identification-production frameworks predict that repetition priming will be reduced by encoding-phase divided attention (DA) in implicit memory tasks that involve conceptual analysis of test stimuli and require responses that go beyond the identification of the test cue. This prediction was tested using the verb generation task. Verb generation priming was weakly affected by a number classification distracting task at encoding that impacted recognition, was affected more by a more demanding mental arithmetic task, and was abolished entirely by a selective attention manipulation. Priming originating largely from a process unique to the verb generation task was also found to be attention-sensitive. DA affected priming equivalently for high-competition and low-competition items, against the identification-production framework which predicts greater DA effects on priming in high-competition conditions. The results fit comfortably within the TAP framework.

Age-related influences on repetition priming in the verb generation task: examining the role of response competition.

The identification-production framework suggests that aging is associated with a decline in production forms of repetition priming, particularly under test conditions that maximize response competition. The present study examined this prediction by testing young and healthy older adults in a single-encoding version of the verb generation task in which some items had one dominant verb response (low competition) or had no such dominant response (high competition). Further analyses examined whether priming and error rates were related to performance on neuropsychological tests purported to measure frontal lobe functioning. Priming was invariant across age groups and was not related to frontal lobe status in older adults, but frontal lobe status did predict task performance: low-frontal older adults made more errors than high-frontal older adults, particularly for high-competition items and items with high association strength. These results are not consistent with the identification-production framework, but are consistent with the conclusions that (a) aging is associated with invariance in the processes that support repetition priming in the verb generation task and (b) frontal lobe status in aging is related to verb generation performance.

Recollection and familiarity in recognition memory: adult age differences and neuropsychological test correlates.

Dual process theories account for age-related changes in memory by proposing that old age is associated with deficits in recollection together with invariance in familiarity. The authors evaluated this proposal in recognition by examining recollection and familiarity estimates in young and older adults across 3 process estimation methods: inclusion/exclusion, remember/know, and receiver operating characteristics (ROC). Consistent with a previous literature review (Light, Prull, LaVoie, & Healy, 2000), the authors found age invariance in familiarity when process estimates were derived from the inclusion/exclusion method, but the authors found age differences favoring the young when familiarity estimates were derived from the remember/know and ROC methods. Recollection estimates were lower for older adults in all 3 methods. Recollection and familiarity had variable relationships with frontal- and temporal-lobe measures of neuropsychological functioning in older adults, depending on which method was used to generate process estimates. These data suggest that although recollection deficits appear to be the rule in aging, not all estimates of familiarity show age invariance.

Relating medial temporal lobe volume to frontal fMRI activation for memory encoding in older adults.

Neuroimaging research on the brain basis of memory decline in older adults typically has examined age-related changes either in structure or in function. Structural imaging studies have found that smaller medial temporal lobe (MTL) volumes are associated with lower memory performance. Functional imaging studies have found that older adults often exhibit bilateral frontal-lobe activation under conditions where young adults exhibit unilateral frontal activation. As yet, no one has examined whether these MTL structural and frontal-lobe functional findings are associated. In this study, we tested whether these findings were correlated in a population of healthy older adults in whom we previously demonstrated verbal memory performance was positively associated with left entorhinal cortex volume in the MTL (Rosen et al., 2003) and right frontal lobe activation during memory encoding (Rosen et al., 2002). Thirteen, non-demented, community-dwelling older adults participated both in a functional MRI (fMRI) study of verbal memory encoding and structural imaging. MRI-derived left entorhinal volume was measured on structural images and entered as a regressor against fMRI activation during verbal memory encoding. Right frontal activation (Brodmann's Area 47/insula) was positively correlated with left entorhinal cortex volume. These findings indicate a positive association between MTL volume and right frontal-lobe function that may underlie variability in memory performance among the elderly, and also suggest a two-stage model of memory decline in aging.

Exploring the identification-production hypothesis of repetition priming in young and older adults.

The identification-production hypothesis of age-related differences in repetition priming predicts reduced priming in older adults on indirect memory measures that require stimulus production (production priming) together with age constancy on indirect measures that require stimulus identification, verification, or classification processes (identification priming). Although some evidence is consistent with this hypothesis, comparisons of identification and production priming in young and older adults often confound stimulus, subject, and dependent measure factors across tasks. Consequently, repetition priming has yet to be assessed in healthy young and healthy older adults using identification and production tasks that control for these factors. The identification-production hypothesis was tested using verb generation as a measure of production priming (Experiments 1-3) and semantic classification (Experiment 1) or semantic verification (Experiments 2 and 3) as the measure of identification priming. Contrary to the identification-production hypothesis, no age-related diminutions in identification or production forms of priming were found.

Differential associations between entorhinal and hippocampal volumes and memory performance in older adults.

Magnetic resonance imaging-derived entorhinal and hippocampal volumes were measured in 14 nondemented, community-dwelling older adults. Participants were selected so that memory scores from 2 years prior to scanning varied widely but were not deficient relative to age-appropriate norms. A median split of these memory scores defined high-memory and low-memory groups. Verbal memory scores at the time of imaging were lower, and entorhinal and hippocampal volumes were smaller, in the low-memory group than in the high-memory group. Left entorhinal cortex volume showed the strongest correlation (r= .79) with immediate recall of word lists. Left hippocampal volume showed the strongest correlation (r= .57) with delayed paragraph recall. These results suggest that entorhinal and hippocampal volumes are related to individual differences in dissociable kinds of memory performance among healthy older adults.

Variable effects of aging on frontal lobe contributions to memory.

Declarative memory declines with age, but there is profound variation in the severity of this decline. Healthy elderly adults with high or low memory scores and young adults viewed words under semantic or non-semantic encoding conditions while undergoing fMRI. Young adults had superior memory for the words, and elderly adults with high memory scores had better memory for the words than those with low memory scores. The elderly with high scores had left lateral and medial prefrontal activations for semantic encoding equal to the young, and greater right prefrontal activation than the young. The elderly with low scores had reduced activations in all three regions relative to the elderly with high memory scores. Thus, successful aging was characterized by preserved left prefrontal and enhanced right prefrontal activation that may have provided compensatory encoding resources.