The structure of working memory abilities across the adult life span

The present study addresses three questions regarding age differences in working memory: (1) whether performance on complex span tasks decreases as a function of age at a faster rate than performance on simple span tasks; (2) whether spatial working memory decreases at a faster rate than verbal working memory; and (3) whether the structure of working memory abilities is different for different age groups. Adults, ages 20-89 (n = 388), performed three simple and three complex verbal span tasks and three simple and three complex spatial memory tasks. Performance on the spatial tasks decreased at faster rates as a function of age than performance on the verbal tasks, but within each domain, performance on complex and simple span tasks decreased at the same rates. Confirmatory factor analyses revealed that domain-differentiated models yielded better fits than models involving domain-general constructs, providing further evidence of the need to distinguish verbal and spatial working memory abilities. Regardless of which domain-differentiated model was examined, and despite the faster rates of decrease in the spatial domain, age group comparisons revealed that the factor structure of working memory abilities was highly similar in younger and older adults and showed no evidence of age-related dedifferentiation.     

Transformations in the couplings among intellectual abilities and constituent cognitive processes across the life span

Abstract— Two-component theories of intellectual development over the life span postulate that fluid abilities develop earlier during child development and decline earlier during aging than crystallized abilities do, and that fluid abilities support or constrain the acquisition and expression of crystallized abilities. Thus, maturation and senescence compress the structure of intelligence by imposing age-specific constraints upon its constituent processes. Hence, the couplings among different intellectual abilities and cognitive processes are expected to be strong in childhood and old age. Findings from a population-based study of 291 individuals aged 6 to 89 years support these predictions. Furthermore, processing robustness, a frequently overlooked aspect of processing, predicted fluid intelligence beyond processing speed in old age but not in childhood, suggesting that the causes of more compressed functional organization of intelligence differ between maturation and senescence. Research on developmental changes in functional brain circuitry may profit from explicitly recognizing transformations in the organization of intellectual abilities and their underlying cognitive processes across the life span.     

Adults' conceptions of intelligence across the adult life span.

To examine whether young, middle-aged, and older adults view the concept of intelligent person as similar or different during adulthood, 140 adults of various ages rated how likely it would be for individuals of average and exceptional intelligence at 30, 50, and 70 years of age to be engaged in behaviors previously identified by adults as characterizing adult intelligence. Adults perceived more similarity between exceptionally intelligent prototypes of closer ages (i.e., 30 and 50 and 50 and 70). Intelligence was perceived to consist of interest and ability to deal with novelty, everyday competence, and verbal competence--dimensions that were perceived to be differentially important for different-aged prototypes and by individuals of different ages. Participants' conceptions also included the idea that intelligence is malleable and that abilities differentially increase or decrease across the life span.     

A model of cognitive development across the life span

A model of cognitive development across the life span was proposed. A distinction was drawn between an individual's unexercised potential, which refers to the level of performance that would be expected if the individual had no exercise and/or training on the ability in question, and an individual's optimally-exercised potential, which refers to the level of performance that would be expected if the individual had optimal exercise and training. Both unexercised and optimally-exercised potential levels were proposed to increase with age up to early adulthood and decrease gradually thereafter. The region between the two types of potential, which was also suggested to increase during childhood and decrease during later adulthood, indicates the extent to which exercise and/or training can affect performance. This model was shown to be consistent with a number of different types of empirical findings.     

Derived Trail Making Test indices: demographics and cognitive background variables across the adult life span

We examined the contribution of demographics and cognitive background variables (processing speed, visuospatial skill, working memory, and interference control) on derived Trail Making Test (TMT) scores in a large sample of Greek healthy participants. We included 775 participants and administered the TMT (TMT-A and TMT-B) and the Wechsler Intelligence Adult Scale (WAIS). Direct (TMT-A & TMT-B time-to-completion) and derived [difference TMT-(B ? A) & ratio TMT-(B/A)] scores were calculated. Demographics (age, age², education, and gender) and WAIS Full Intelligence Quotient significantly predicted the direct TMT-A (R² = 0.426) and TMT-B (R² = 0.593) scores and to a lesser extent, the derived TMT-(B ? A) (R² = 0.343) and TMT-(B/A) (R² = 0.088) scores. In a subsample of 537 healthy participants who also completed the Stroop Neuropsychological Screening Test (SNST), demographics (age and education), WAIS Digit Symbol, Block Design, Arithmetic, and SNST accounted for 44.8% and 59.7% of the variance on TMT-A and TMT-B, and 32.5% and 9.6% of the variance on TMT-(B ? A) and TMT-(B/A), respectively. We found minimal influence of Block Design and Arithmetic on TMT-(B ? A) and an absence of significant influence of any cognitive variable on TMT-(B/A) score. Concluding, derived TMT scores are suggested as indices to detect impairment in cognitive flexibility across the adult life span, since they minimize the effect of demographics and other cognitive background variables.     

Neuromodulation of behavioral and cognitive development across the life span

Among other mechanisms, behavioral and cognitive development entail, on the one hand, contextual scaffolding and, on the other hand, neuromodulation of adaptive neurocognitive representations across the life span. Key brain networks underlying cognition, emotion, and motivation are innervated by major transmitter systems (e.g., the catecholamines and acetylcholine). Thus, the maturation and senescence of neurotransmitter systems have direct implications for life span development. Recent progress in molecular genetics has opened new avenues for investigating neuromodulation of behavioral and cognitive development. This special section features 6 selected reviews of recent cognitive genetic evidence on the roles of dopamine and other transmitters in different domains of behavioral and cognitive development, ranging from temperament, executive control, and working memory to motivation and goal-directed behavior in different life periods.     

Age-related changes in the efficiency of cognitive processing across the life span

The global-speed and the specific-gain/loss hypotheses have been dominant theoretical frameworks in the recent literature on cognitive development and aging. Few attempts have been made to explicitly assess the predictive power of the two frameworks against each other. We evaluated the extent to which age changes in performance in executive function tasks (involving response selection, response suppression, working memory, and adaptive control) depend on age-related changes in global information-processing speed. Our sample consisted of children, adolescents, adults and seniors. Analysis of covariance and structural equation modeling revealed a mixed pattern of results. Controlling for global speed removed the child vs. adult differences in the speed of responding on the executive function tasks but the senior vs. adult differences remained. This mixed pattern of findings was interpreted to suggest that the effects of advancing age on the speed of responding are mediated by a global mechanism during childhood but during senescence the efficiency of executive functioning seems particularly vulnerable to the effects of age.     

The relationship between women's body satisfaction and self-image across the life span: the role of cognitive control

The authors examined the relationship between body dissatisfaction and self-image across the life span. A sample of 106 women between the ages of 20 and 65 years completed questionnaire measures of body dissatisfaction, body importance, cognitive control over the body, self-concept, and self-esteem. The authors found that body dissatisfaction and body importance did not differ among the groups of women who were younger, middle aged, and older. Although body dissatisfaction was related to self-concept and self-esteem for the entire sample, the strength of that relationship reduced with increasing age and increasing perceptions of cognitive control. The authors concluded that the cognitive strategies of women who were older protect their self-concept and self-esteem from the influence of body dissatisfaction.     

Attachment and the processing of social information across the life span: theory and evidence

Researchers have used J. Bowlby's (1969/1982, 1973, 1980, 1988) attachment theory frequently as a basis for examining whether experiences in close personal relationships relate to the processing of social information across childhood, adolescence, and adulthood. We present an integrative life-span-encompassing theoretical model to explain the patterns of results that have emerged from these studies. The central proposition is that individuals who possess secure experience-based internal working models of attachment will process--in a relatively open manner--a broad range of positive and negative attachment-relevant social information. Moreover, secure individuals will draw on their positive attachment-related knowledge to process this information in a positively biased schematic way. In contrast, individuals who possess insecure internal working models of attachment will process attachment-relevant social information in one of two ways, depending on whether the information could cause the individual psychological pain. If processing the information is likely to lead to psychological pain, insecure individuals will defensively exclude this information from further processing. If, however, the information is unlikely to lead to psychological pain, then insecure individuals will process this information in a negatively biased schematic fashion that is congruent with their negative attachment-related experiences. In a comprehensive literature review, we describe studies that illustrate these patterns of attachment-related information processing from childhood to adulthood. This review focuses on studies that have examined specific components (e.g., attention and memory) and broader aspects (e.g., attributions) of social information processing. We also provide general conclusions and suggestions for future research.     

Global self-esteem across the life span

This study provides a comprehensive picture of age differences in self-esteem from age 9 to 90 years using cross-sectional data collected from 326,641 individuals over the Internet. Self-esteem levels were high in childhood, dropped during adolescence, rose gradually throughout adulthood, and declined sharply in old age. This trajectory generally held across gender, socioeconomic status, ethnicity, and nationality (U.S. citizens vs. non-U.S. citizens). Overall, these findings support previous research, help clarify inconsistencies in the literature, and document new trends that require further investigation.     

Executive function across the life span

The development and determinants of executive function (EF) were studied in children (mean age=8.8 years), young adults ( M= 22.3 years), and elderly adults (M = 7 years). EF was indexed by perseverative responding on two bidimensional sorting tasks (Visually Cued Color-Shape task and Auditorily Cued Number-Numeral task), and age-related changes in EF were considered in relation to estimates of conscious vs. unconscious memory that were obtained using the process dissociation procedure (PDP). Results revealed the rise and fall of EF across the life span, with significant quadratic trends found for performance on both sorting tasks and for the conscious recollection component (C) of the PDP task. Regression analyses indicated that PDP estimates of conscious memory accounted for variation in performance on the visual sorting task, but not on the auditory sorting task. The findings are discussed in terms of their implications for hierarchical models of EF and its development.     

Visual search across the life span

Gains and losses in visual search were studied across the life span in a representative sample of 298 individuals from 6 to 89 years of age. Participants searched for single-feature and conjunction targets of high or low eccentricity. Search was substantially slowed early and late in life, age gradients were more pronounced in conjunction than in feature search, and all age groups were uniformly affected by eccentricity manipulations. However, developmental and aging trends were distinctly asymmetrical: Children's performance was particularly affected by the mere presence of distractors; whereas in late life, performance was particularly impaired on target-absent trials and with increasing numbers of distractors. The implications for life span theories of cognitive and attentional development and for cognitive-speed and inhibitory-control accounts are discussed.     

Competitiveness across the life span: the feisty fifties

Existing theories on life span changes in confidence or motivation suggest that individuals' preferences to enter competitive situations should gradually decline with age. We examined competitive preferences in a field experiment using real financial stakes in 25- to 75-year-olds (N = 543). The critical dependent variable was whether participants chose to perform a simple mental arithmetic task either under a piece-rate payment schedule (i.e., $.25 per solved item) or a competitive payment schedule ($.50 per solved item if the overall score is better than that of a randomly selected opponent, $0 otherwise). Results revealed that competitive preferences increased across the life span until they peaked around age 50, and dropped thereafter. We also found that throughout, men had a substantially larger preference for competing than women-extending previous findings on college-aged participants. The age/gender differences in preferences were neither accounted for by actual differences in performance nor individuals' subjective confidence. This first systematic attempt to characterize age differences in competitive behavior suggests that a simple decline conception of competitiveness needs to be reconsidered.     

Stability of self-esteem across the life span

Two studies examined the rank-order stability of self-esteem from age 6 to 83: Study 1 was a meta-analysis of 50 published articles (N = 29,839) and Study 2 analyzed data from 4 large national studies (N = 74,381). Self-esteem showed substantial continuity over time (disattenuated correlations ranged from the .50s to .70s), comparable to the stability found for personality traits. Both studies provided evidence for a robust developmental trend: Self-esteem stability was low during childhood, increased throughout adolescence and young adulthood, and declined during midlife and old age. This trend could not be explained by age differences in the reliability of self-esteem measures, and generally replicated across gender, ethnicity, self-esteem scale, nationality (U.S. vs. non-U.S.), and year of publication.     

The generous elderly: naturalistic studies of donations across the life span

The relation between age and altruism was examined in two experiments conducted in naturalistic settings. In both studies, individuals from 5 to over 75 years of age had opportunities to donate money to a charity concerned with the welfare of infants with birth defects. The effect of a variable designed to evoke the needs rule was also observed by using both pregnant and nonpregnant charitable solicitors. Results of both studies yielded a significant main effect of solicitor condition on donations. Study 1 yielded a linear increase with age in numbers of people donating; however, retired persons generally donated less money than did younger adults. In Study 2, which controlled for financial costs, elderly persons proved to be the most generous. These results underscore the importance of personal resources and helping opportunities in influencing altruism among older persons.     

Naming ability across the adult life span

Abstract

Longitudinal performance on the Boston Naming Test (BNT) was evaluated in 53 normal subjects aged 30 to 79 who were each tested three times over a 7-year span. Naming performance showed a significant decline over time that was greatest for the oldest subjects. These results confirm that decline in naming is a real phenomenon in normal aging that cannot be attributable primarily to cohort effects. We conclude that the changes in naming ability across the life span reflect more than simply a breakdown in lexical retrieval and that perceptual and semantic processing may be implicated.     

The place of social intelligence in a taxonomy of cognitive abilities

Studies have yielded inconsistent results regarding the place of social intelligence in a taxonomy of cognitive abilities. An investigation is described in which measures of social behaviors obtained from interviews were related to a wide variety of cognitive variables. Significant relations were rare. It is suggested that the question to be posed is not the simple one of the place of social intelligence in the cognitive domain but rather one of the relationships of the elements of two large taxonomic systems. A Taxonomy of social intelligence would provide a set of definitions procedures that would improve efforts to replicate and build on previous research. More important would be the heuristic value of a structural representation of “social intelligence” based on theoretical relationships involving environmental, physiological, and genetic as well as psychological factors. Development of a taxonomy of situations would facilitate the study of interactions involving performance and environmental conditions.     

CHC theory and the human cognitive abilities project: Standing on the shoulders of the giants of psychometric intelligence research

During the past decade the Cattell–Horn Gf–Gc and Carroll Three-Stratum models have emerged as the consensus psychometric-based models for understanding the structure of human intelligence. Although the two models differ in a number of ways, the strong correspondence between the two models has resulted in the increased use of a broad umbrella term for a synthesis of the two models (Cattell–Horn–Carroll theory of cognitive abilities—CHC theory).The purpose of this editorial is three-fold. First, I will describe the CHC framework and recommend that intelligence researchers begin using the CHC taxonomy as a common nomenclature for describing research findings and a theoretical framework from which to test hypotheses regarding various aspects of human cognitive abilities. Second, I argue that the emergence of the CHC framework should not be viewed as the capstone to the psychometric era of factor analytic research. Rather, I recommend the CHC framework serve as the stepping stone to reinvigorate the investigation of the structure of human intelligence.Finally, the Woodcock-Muñoz Foundation Human Cognitive Abilities (HCA) project, which is an evolving, free, on-line electronic archive of the majority of datasets analyzed in Carroll's (1993) seminal treatise on factor analysis of human cognitive abilities, is introduced and described. Intelligence scholars are urged to access the Carroll HCA datasets to test and evaluate structural models of human intelligence with contemporary methods (confirmatory factor analysis). In addition, suggestions are offered for linking the analysis of contemporary data sets with the seminal work of Carroll. The emergence of a consensus CHC taxonomy and access to the original datasets analyzed by Carroll provides an unprecedented opportunity to extend and refine our understanding of human intelligence.     

Recognition memory across the adult life span: The role of prior knowledge

Two experiments were performed to investigate the effects of prior knowledge on recognition memory in young adults, younger old adults, 76-year-olds, and 85-year-olds. In Experiment 1, we examined episodic recognition of dated and contemporary famous persons presented as faces, names, and faces plus names. In Experiment 2, four types of faces were presented for later recognition: dated familiar, contemporary familiar, old unfamiliar, and young unfamiliar. The results of both experiments showed that young adults performed better with contemporary than with dated famous persons, whereas the reverse was true for all groups of older adults. In addition, the data of Experiment 2 indicated that (1) young adults showed better recognition for young than for old unfamiliar faces, (2) younger old adults performed better with old than with young unfamiliar faces, and (3) the two oldest age groups showed no effect of age of face. These results suggest that the ability to utilize rich semantic knowledge to improve episodic memory is preserved in very old age, although the aging process may be associated with deficits in the ability to utilize prior knowledge to support memory when the underlying representation lacks semantic and contextual features. The overall data pattern was discussed in relation to the notion that, with increasing adult age, there is an increase in the level of cognitive support required to enhance episodic remembering.