Medial temporal lobe volume predicts elders' everyday memory.

Deficits in memory for everyday activities are common complaints among healthy and demented older adults. The medial temporal lobes and dorsolateral prefrontal cortex are both affected by aging and early-stage Alzheimer's disease, and are known to influence performance on laboratory memory tasks. We investigated whether the volume of these structures predicts everyday memory. Cognitively healthy older adults and older adults with mild Alzheimer's-type dementia watched movies of everyday activities and completed memory tests on the activities. Structural MRI was used to measure brain volume. Medial temporal but not prefrontal volume strongly predicted subsequent memory. Everyday memory depends on segmenting activity into discrete events during perception, and medial temporal volume partially accounted for the relationship between performance on the memory tests and performance on an event-segmentation task. The everyday-memory measures used in this study involve retrieval of episodic and semantic information as well as working memory updating. Thus, the current findings suggest that during perception, the medial temporal lobes support the construction of event representations that determine subsequent memory.

Brain activation during interference resolution in young and older adults: an fMRI study.

A rapid event-related fMRI arrow flanker task was used to study aging-associated decline in executive functions related to interference resolution. Older adults had more difficulty responding to Incongruent cues during the flanker task compared to the young adults; the response time difference between the Incongruent and Congruent conditions in the older group was over 50% longer compared to the young adults. In the frontal regions, differential activation ("Incongruent-Congruent" conditions) was observed in the inferior and middle frontal gyri in within-group analyses for both groups. However, the cluster was smaller in the older group and the centroid location was shifted by 19.7 mm. The left superior and medial frontal gyri also appeared to be specifically recruited by older adults during interference resolution, partially driven by errors. The frontal right lateralization found in the young adults was maintained in the older adults during successful trials. Interestingly, bilateral activation was observed when error trials were combined with successful trials highlighting the influence of brain activation associated with errors during cognitive processing. In conclusion, aging appears to result in modified functional regions that may contribute to reduced interference resolution. In addition, error processing should be considered and accounted for when studying age-related cognitive changes as errors may confound the interpretation of task specific age-related activation differences.

Age-related differences in cognition: the role of distraction control.

The ability to ignore or control the processing of distracting information may underlie many age-related and individual differences in cognitive abilities. Using a large sample of adults aged 18 to 87 years, this article presents data examining the mediating role of distraction control in the relationship between age and higher order cognition. The reading with distraction task (Connelly, Hasher, & Zacks, 1991) has been used as a measure of the access function of distraction control. Results of this study suggest that distraction control, as measured by this paradigm, plays an important role in mediating age-related effects on measures of working memory and matrix reasoning.

Aging and a benefit of distractibility.

Under instructions to ignore distraction, younger and older adults read passages with interspersed distracting words. Some of the distractors served as solutions to a subsequent set of verbal problems in which three weakly related words could be related by retrieving a missing fourth word (i.e., the Remote Associates Test [RAT]; Mednick, 1962). Older adults showed significant priming from the distraction, whereas younger adults did not. In this study, we present a case in which age-related reductions in attentional control over information that was not initially relevant can actually lead to superior performance for older adults. The RAT materials may be downloaded from www.psychonomic.org/archive.

Age deficits in the control of prepotent responses: evidence for an inhibitory decline.

Older adults have more difficulty than younger adults appropriately directing their behavior when the required response is in competition with a prepotent response. The authors varied the difficulty of inhibiting a prepotent eye movement response by varying the response cue (peripheral onset or central arrow). The response cue manipulation did not affect prosaccade accuracy and latency for either age group and did not affect younger adults' antisaccades. Older adults' antisaccades were slower in the peripheral cue condition than in the central arrow condition. These findings are taken as support for the inhibitory deficit hypothesis of aging (L. Hasher, R. T. Zacks, & C. P. May, 1999).

Psychology and Aging: the first 20 years.

This article provides a review of the first 20 years of Psychology and Aging, the American Psychological Association's first and only scholarly journal devoted to the topic of aging. The authors briefly summarize its history, its contributions to the study of aging, and its broader status as a scholarly publication. One theme highlighted in our review is the diversity of content in the journal throughout its history. Another is the strong impact that articles published in the journal have had on both basic and applied topics in aging. Efforts to encompass the breadth of topics and methodologies in aging research while retaining excellent quality remain the exciting but essential challenge for Psychology and Aging.

Age and inhibition: the retrieval of situation models.

We present a test of whether age-related differences in the management of interference during memory retrieval can be explained, at least in part, by decreased inhibitory mechanisms in older adults. We conducted this test by measuring the ease of retrieval of situation model representations that were sources of interference on the preceding trial but that contained the target information for the current trial. Prior research has shown that situation model retrieval under these conditions exhibits inhibition relative to an unrelated control. This effect was replicated in the current study for younger but not older adults; at the same time, the older adults showed greater overall retrieval interference than the younger adults. This pattern is consistent with the idea that there are declines in inhibitory processing in older adults, and that this applies to memory retrieval.

Framing effects in younger and older adults.

A growing literature on decision making in older adults suggests that they are more likely to use heuristic processing than are younger adults. We assessed this tendency in the context of a framing effect, a decision-making phenomenon whereby the language used to describe options greatly influences the decision maker's choice. We compared decision making under a standard ("heuristic") condition and also under a "justification" condition known to reduce reliance on heuristics. In the standard condition, older adults were more susceptible than younger adults to framing but the two groups did not differ when participants were asked to provide a justification. Thus, although older adults may spontaneously rely more on heuristic processing than younger adults, they can be induced to take a more systematic approach to decision making.

Inhibitory changes after age 60 and their relationship to measures of attention and memory.

This study examined the relationship between age and inhibitory functioning within a sample of older adults ranging in age from 60 to 85 years old. On the basis of earlier research, and confirmed by factor analysis, measures typically referred to as frontal lobe tasks were used as measures of inhibitory functioning. Findings demonstrated that inhibitory processes continued to decline with advancing age within the older sample. In addition, the role of inhibition in age-related performance deficits on a verbal list learning measure and an attention measure was examined. Hierarchical regression analyses showed that inhibition accounted for a significant proportion of the age-related variance on the two cognitive measures, whereas measures of reading speed accounted for a smaller proportion of the variance. In addition, when inhibition was first covaried out, reading speed no longer accounted for a significant proportion of the age-related variance. It is argued that inhibition is an important contributor to age-related performance decrements in cognition.

Stroop interference, practice, and aging.

We report two experiments that investigate practice effects on Stroop color-word interference in older and younger adults. Both experiments employed a computerized, single-item version of the Stroop task with a voice response, and both involved practice over hundreds of trials. Both experiments showed generally similar practice patterns, including a practice-related reduction in the size of the color-word interference effect. However, the older group continued to show a larger interference effect throughout practice. These findings indicate that older adults show the same trend in practice-related improvement on the Stroop task as younger adults.

Event segmentation ability uniquely predicts event memory.

Memory for everyday events plays a central role in tasks of daily living, autobiographical memory, and planning. Event memory depends in part on segmenting ongoing activity into meaningful units. This study examined the relationship between event segmentation and memory in a lifespan sample to answer the following question: Is the ability to segment activity into meaningful events a unique predictor of subsequent memory, or is the relationship between event perception and memory accounted for by general cognitive abilities? Two hundred and eight adults ranging from 20 to 79years old segmented movies of everyday events and attempted to remember the events afterwards. They also completed psychometric ability tests and tests measuring script knowledge for everyday events. Event segmentation and script knowledge both explained unique variance in event memory above and beyond the psychometric measures, and did so as strongly in older as in younger adults. These results suggest that event segmentation is a basic cognitive mechanism, important for memory across the lifespan.

Age differences in what is viewed and remembered in complex conjunction search.

Older and younger adults searched arrays of 12 unique real-world photographs for a specified object (e.g., a yellow drill) among distractors (e.g., yellow telephone, red drill, and green door). Eye-tracking data from 24 of 48 participants in each age group showed generally similar search patterns for the younger and older adults but there were some interesting differences. Older adults processed all the items in the arrays more slowly than the younger adults (e.g., they had longer fixation durations, gaze durations, and total times), but this difference was exaggerated for target items. We also found that older and younger adults differed in the sequence in which objects were searched, with younger adults fixating the target objects earlier in the trial than older adults. Despite the relatively longer fixation times on the targets (in comparison to the distractors) for older adults, a surprise visual recognition test revealed a sizeable age deficit for target memory but, importantly, no age differences for distractor memory.

Younger and Older Adults' "Good-Enough" Interpretations of Garden-Path Sentences.

We report 3 experiments that examined younger and older adults' reliance on "good-enough" interpretations for garden-path sentences (e.g., "While Anna dressed the baby played in the crib") as indicated by their responding "Yes" to questions probing the initial, syntactically unlicensed interpretation (e.g., "Did Anna dress the baby?"). The manipulation of several factors expected to influence the probability of generating or maintaining the unlicensed interpretation resulted in 2 major age differences: Older adults were generally more likely to endorse the incorrect interpretation for sentences containing optionally transitive verbs (e.g., hunted, paid), and they showed decreased availability of the correct interpretation of subordinate clauses containing reflexive absolute transitive verbs (e.g., dress, bathe). These age differences may in part be linked to older adults' increased reliance on heuristic-like good-enough processing to compensate for age-related deficits in working memory capacity. The results support previous studies suggesting that syntactic reanalysis may not be an all-or-nothing process and might not be completed unless questions probing unresolved aspects of the sentence structure challenge the resultant interpretation.

Incidental visual memory for targets and distractors in visual search.

We explored incidental retention of visual details of encountered objects during search. Participants searched for conjunction targets in 32 arrays of 12 pictures of real-world objects and then performed a token discrimination task that examined their memory for visual details of the targets and distractors from the search task. The results indicate that even though participants had not been instructed to memorize the objects, the visual details of search targets and distractor objects related to the targets were retained after the search. Distractor objects unrelated to the search target were remembered more poorly. Eye-movement measures indicated that the objects that were remembered were looked at more frequently during search than those that were not remembered. These results provide support that detailed visual information is included incidentally in the visual representation of an object after the object is no longer in view.

Age preservation of the syntactic processor in production.

Two experiments are reported on the influence of cognitive aging on grammatical choice in language production. In both experiments, participants from two age-groups (young and old) produced sentences in a formulation task (V. Ferreira, 1996) that contrasted conditions allowing a choice between alternative sentence arrangements (i.e., double object or prepositional dative) or that permitted no choice (i.e., prepositional dative only). Experiment 1 showed that older adults were able to formulate the alternative sentence arrangements with the same speed and fluency as young adults. Experiment 2 showed that cueing attention to one of the two object nouns to be included in the sentence resulted in the earlier expression of the cued noun in choice conditions, but with little evidence of a response time or dysfluency cost in the no-choice condition. As in Experiment 1, there were no substantive age differences in latencies or dysfluencies. These results support existing models for the mechanisms that choose between grammatical alternatives and bind phrases to available argument positions and provide evidence that older adults are not impaired in their use of these mechanisms.