Faculty Bibliography

Five studies were conducted to examine the nature of life satisfaction judgments. When the category of "excitement" was made accessible experimentally, individuals based their life satisfaction judgments more heavily on the frequency of excitement, in comparison to a "peaceful" condition in Study 1 and to both "neutral priming" and "no-priming" conditions in Study 2. A 7-day diary study (Study 3) showed that as "excitement" became naturally more accessible on weekends, the correlations between excitement and daily satisfaction also increased significantly. Study 3 thus illustrated a systematic contextual shift in the bases of life satisfaction judgments. Study 4 showed that high sensation seekers, for whom "excitement" should be chronically accessible, based their life satisfaction judgments more heavily on the frequency of excitement than did low sensation seekers. Finally, Study 5 demonstrated that the chronic accessibility of "excitement" measured at Time 1 predicted the degree to which individuals based their life satisfaction judgments on the frequency of excitement at Time 2. Altogether, these five studies highlight the contextually sensitive, yet systematic nature of life satisfaction judgments. © 2003 Elsevier Science (USA). All rights reserved.

This study investigated the hypothesis that age differences in memory performance may be influenced by stereotype threat associated with negative cultural beliefs about the impact of aging on memory. Recall was examined in 48 young and 48 older adults under conditions varying in the degree of induced threat. Conditions that maximize threat resulted in lower performance in older adults relative to both younger adults and to older adults who did not experience threat. The degree to which threat affected older adults' performance increased along with the value that these individuals placed on their memory ability. Older adults' memory performance across experimental conditions was observed to covary with degree of activation of the negative aging stereotype, providing support for the hypothesized relationship between stereotype activation and performance. Finally, stereotype threat also influenced mnemonic strategy use, which in turn partially mediated the impact of threat on recall. These results emphasize the important role played by contextual factors in determining age differences in memory performance.

BACKGROUND:The human brain gradually loses tissue from the third decade of life onward, with concomitant declines in cognitive performance. Given the projected rapid growth in aged populations, and the staggering costs associated with geriatric care, identifying mechanisms that may reduce or reverse cerebral deterioration is rapidly emerging as an important public health goal. Previous research has demonstrated that aerobic fitness training improves cognitive function in older adults and can improve brain health in aging laboratory animals, suggesting that aerobic fitness may provide a mechanism to improve cerebral health in aging humans. We examined the relationship between aerobic fitness and in vivo brain tissue density in an older adult population, using voxel-based morphometric techniques. METHODS:We acquired high-resolution magnetic resonance imaging scans from 55 older adults. These images were segmented into gray and white matter maps, registered into stereotaxic space, and examined for systematic variation in tissue density as a function of age, aerobic fitness, and a number of other health markers. RESULTS:Consistent with previous studies of aging and brain volume, we found robust declines in tissue densities as a function of age in the frontal, parietal, and temporal cortices. More importantly, we found that losses in these areas were substantially reduced as a function of cardiovascular fitness, even when we statistically controlled for other moderator variables. CONCLUSIONS:These findings extend the scope of beneficial effects of aerobic exercise beyond cardiovascular health, and they suggest a strong solid biological basis for the benefits of exercise on the brain health of older adults.

A meta-analytic study was conducted to examine the hypothesis that aerobic fitness training enhances the cognitive vitality of healthy but sedentary older adults. Eighteen intervention studies published between 1966 and 2001 were entered into the analysis. Several theoretically and practically important results were obtained. Most important fitness training was found to have robust but selective benefits for cognition, with the largest fitness-induced benefits occurring for executive-control processes. The magnitude of fitness effects on cognition was also moderated by a number of programmatic and methodological factors, including the length of the fitness-training intervention, the type of the intervention, the duration of training sessions, and the gender of the study participants. The results are discussed in terms of recent neuroscientific and psychological data that indicate cognitive and neural plasticity is maintained throughout the life span.

The present experiment examined the degree to which experience with different stimulus characteristics affects attentional capture, particularly as related to aging. Participants were presented with onset target/color singleton distractor or color singleton target/onset distractor pairs across three experimental sessions. The target/distractor pairs were reversed in the second session such that the target in the first session became the distractor in the second and third sessions. For both young and old adults previous experience with color as a target defining feature influenced oculomotor capture with task-irrelevant color distractors. Experience with sudden onsets had the same effect for younger and older adults, although capture effects were substantially larger for onset than for color distractors. Experience-based capture effects diminished relatively rapidly after target and distractor-defining properties were reversed. The results are discussed in terms of top-down and stimulus-driven effects on age-related differences in attentional control.

The present article provides a brief review of the human and animal literature that has investigated the relationship between fitness training and brain and cognitive function. The animal research clearly suggests that improvements in fitness can lead to both morphological and functional changes in the brains of older animals. Results of a recent meta-analysis suggest that fitness training can also have beneficial effects on human cognition, particularly on tasks requiring executive control processing. These effects are also moderated by a number of factors, including the proportion of men and women in the intervention studies, the length of training sessions, the age of the participants, and the combination of fitness training regimes. The article also discusses preliminary results that link, for the first time, fitness training and differences in human brain structure and function. Finally, we discuss the important issue of participant adherence to fitness training programs and the factors that influence fitness participation.

While limited research is available, evidence indicates that physical and mental activity influence the aging process. Human data show that executive functions of the type associated with frontal lobe and hippocampal regions of the brain may be selectively maintained or enhanced in humans with higher levels of fitness. Similarly enhanced performance is observed in aged animals exposed to elevated physical and mental demand and it appears that the vascular component of the brain response may be driven by physical activity whereas the neuronal component may reflect learning. Recent results have implicated neurogenesis, at least in the hippocampus, as a component of the brain response to exercise, with learning enhancing survival of these neurons. Non-neuronal tissues also respond to experience in the mature brain, indicating that the brain reflects both its recent and its longer history of experience. Preliminary measures of brain function hold promise of increased interaction between human and animal researchers and a better understanding of the substrates of experience effects on behavioral performance in aging.

Four experiments investigated the conditions in which people use a prototypic event sequence to comprehend a situation-specific sequence of events. Results of Experiment 1 confirmed Trafimow and Wyer's (1993) findings that when participants use a prototype (e.g., a cultural script) to comprehend a new sequence of events concerning a hypothetical person, events that are thematically unrelated to the prototype facilitate the recall of prototypic ones. When participants do not employ a prototype, however, thematically unrelated events interfere with the recall of the prototypic ones. These findings establish a criterion for determining whether prototypes are used as a basis for comprehending an event sequence. Experiment 2 showed that the formation and use of a prototype to comprehend a novel event sequence increases with the number of exemplars to which persons have been exposed before the sequence is encountered. However, Experiments 3 and 4 indicated that people often do not use prototypes to interpret sequences of behaviors that they imagine either themselves or a well-known other performing. This is true even though they personally perform the sequence of behaviors on a daily basis and even though a prototypic representation of the event sequence exists in memory.