Paul Verhaeghen

Aging, executive control, and attention: a review of meta-analyses.

We review the results of a series of meta-analyses by the first author and colleagues, examining age-related differences in selective attention (Stroop-task survey and negative-priming task survey) and in divided attention (dual-task survey and task-switching survey). The four task families all lent themselves to state trace analysis, in which performance in baseline conditions was contrasted with performance in experimental conditions separately for college-aged subjects and for elderly subjects. These analyses found no age-related deficits specific to selective attention or local task-switching. Age deficits were found for dual-task performance and global task-switching. Unlike selective attention and local task-switching costs, dual-task and global task-switching costs were found to be additive in both young and old subjects, unmodulated by task difficulty. These forms of executive intervention then did not alter computational processes already present in the simple tasks, but rather added one or more additional processing steps or stages to the processing stream. The cost was greater in older adults, but was limited to those experimental conditions that activated multiple task sets.

Aging and vocabulary scores: a meta-analysis.

Vocabulary scores were examined in a total of 210 articles, containing 324 independent pairings of younger and older adults, from the 1986-2001 issues of Psychology and Aging. The average effect size, favoring the old, was 0.80 SD. Production tests yielded smaller effects (0.68 SD) than multiple-choice tests (0.93 SD). Both age and education were found to be partially independent determinants of performance in production tests; age effects disappeared in multiple-choice tests as soon as education was taken into account. In addition, the Wechsler Adult Intelligence Scale--Revised Vocabulary subtest (D. Wechsler, 1981) was also found to be sensitive to the Flynn effect (J. R. Flynn, 1987; i.e., increasing test scores with advancing birth year). The results question the approach of using age-group equality in vocabulary scores as a check on sample equivalence.

Aging and dual-task performance: A meta-analysis

The relations between dual-task effects and aging were examined through a meta-analysis of 33 studies (with 48 independent participant groups) using latency as the dependent measure and 30 studies (with 40 independent participant groups) focusing on accuracy. Brinley plots and state traces were derived, and a model to explicate different types of complexity (additive and multiplicative) was developed. The effects of dual-task processing on latency were additive, and this additive cost was larger in older adults than in younger adults and larger than predicted from general slowing. This cost was small and independent of task complexity. The effects of dual-task processing on logit-transformed accuracy were likewise additive, but no specific age deficit was associated with this dual-task cost.

Aging and the Stroop effect : A meta-analysis

In this meta-analysis, data from 20 studies comparing younger and older adults on the Stroop interference effect, contained in 15 articles, were analyzed. No significant difference was found in the Stroop interference effect, expressed as mean standardized difference, between the 2 age groups (for younger adults: d = 2.04; for older adults: d = 2.17). Moderator variables were present, but these did not produce age differences. Brinley analysis showed that a single regression line with a slowing factor of 1.9 described the data well (R2 = .83) and confirmed that no Age x Condition interaction was present in the data. Likewise, no Age x Condition interaction was found when the data were fitted to the information loss model; the age ratio of decay rates was estimated to be 1.4. Consequently, the apparent age-sensitivity of the Stroop interference effect appears to be merely an artifact of general slowing.

The Fate of Cognition in Very Old Age: Six-Year Longitudinal Findings in the Berlin Aging Study (BASE)

The authors report full-information longitudinal age gradients in 4 intellectual abilities on the basis of 6-year longitudinal changes in 132 individuals (mean age at T1 = 78.27, age range = 70-100) from the Berlin Aging Study. Relative to the cross-sectional parent sample (N = 516, mean age at T1 = 84.92 years), this sample was positively selected because of differential mortality and experimental attrition. Perceptual speed, memory, and fluency declined with age. In contrast, knowledge remained stable up to age 90, with evidence for decline thereafter. Age gradients were more negative in old old (n = 66, mean age at T1 = 83.04) than in old (n = 66, mean age at T1 = 73.77) participants. Rates of decline did not differ reliably between men and women or between participants with high versus low life-history status. They conclude that intellectual development after age 70 varies by distance to death, age, and intellectual ability domain.

Ageing and switching of the focus of attention in working memory: results from a modified N-Back task

We conducted two experiments using a modified version of the N-Back task. For younger adults, there was an abrupt increase in reaction time of about 250 ms in passing from N = 1 to N > 1, indicating a cost associated with switching of the focus of attention within working memory. Response time costs remained constant over the range N = 2 to N = 5. Accuracy declined steadily over the full range of N (Experiment 1). Focus switch costs did not interact with either working memory updating (Experiment 1), or global task switching (Experiment 2). There were no age differences in RT costs once general slowing was taken into account, but there was a larger focus-switch-related accuracy cost in older adults than in younger adults. No age sensitivity was found for either updating or global task switching. The results suggest (a) that focus switching is a cognitive primitive, distinct from task switching and updating, and (b) that focus switching shows a specific age-related deficit in the accuracy domain.

Aging and the negative priming effect: A meta-analysis.

This article reports results from a meta-analysis on adult age differences in the negative priming effect (21 studies on identity negative priming and 8 on location negative priming). Both younger and older adults were found to be susceptible to the negative priming effect in identity and location tasks. Effect sizes were homogeneous for both tasks, indicating that the data are adequately described without reference to moderator variables. State trace analysis on identity tasks, in which mean latencies in negative priming conditions were regressed onto mean latencies in baseline conditions, showed (a) that in both age groups the negative priming effect is proportional rather than additive and (b) that the negative priming effect is smaller in older adults as compared with younger adults.

Trait anger, anger expression, and ambulatory blood pressure: A meta-analytic review

A meta-analysis of 15 studies was conducted to investigate the relationship between trait anger and ambulatory blood pressure. Overall, the experience of anger was significantly and positively associated with systolic blood pressure (r+ = 0.049), but not reliably associated with diastolic blood pressure (r+ = 0.028). After removing an outlier, the expression of anger was found to have a reliable inverse relationship with diastolic blood pressure (r+ = −0.072). No reliable relationship between expression of anger and systolic blood pressure (r+ = −0.041) was found. These results continue to support the modest role of self-reported trait anger and anger expression in blood pressure levels. Several suggestions for future research are discussed, including increasing the focus on the complexity and synergism of these effects.

Adult age and Digit Symbol Substitution performance: A meta-analysis

This article reports the results of a meta-analysis of the effects of age, education, and estimated year of measurement on scores from the Wechsler Adult Intelligence Scale and the Wechsler Adult Intelligence Scale-Revised Digit Symbol Substitution Test. Analysis of effect sizes for age reported in 141 studies published between 1986 and 2002 indicated a mean standardized difference of -2.07. Age accounted for 86% of the variance in a regression model using age, education, and year submitted as predictors of Digit Symbol scores. There was no association between years of education or year submitted and Digit Symbol scores for younger adults or older adults.

Relation between cardiovascular and metabolic disease and cognition in very old age: cross-sectional and longitudinal findings from the berlin aging study.

This study documented findings on the relation between cognitive functioning (perceptual speed, memory, fluency, and knowledge) and cardiovascular and metabolic disease in a sample of very old adults (ages 70 and older), both cross-sectionally (n=516) and longitudinally (n=206) in a 4-year follow-up. After age, SES, sex, and dementia status were controlled for, 4 diagnoses were negatively associated with cognition: congestive heart failure, stroke, coronary heart disease, and diabetes mellitus, with a joint effect of 0.47 standard deviations. The impact of disease status was largest on perceptual speed and fluency, memory was impacted only by diabetes, and knowledge was not related to any somatic diagnosis. There was no differential decline in participants diagnosed with 1 of these 4 diseases and those who were not. The only cardiovascular risk factor associated with cognitive performance was alcohol consumption.