Individual Differences In Age Research Articles

Neurobiological substrates of behavioral decline: Models and data analytic strategies for individual differences in aging

Neurobiological substrates of behavioral decline: Models and data analytic strategies for individual differences in aging

Age, information processing speed, and intelligence.

Two parallel, but independent, literatures have grown out of observations that individual differences in information processing speed, as expressed in performance on choice reaction time (C RT) tasks, modestly correlate with individual differences in age and IQ test performance. These associations have prompted theories that individual differences in information processing speed functionally determine individual differences in performance of all cognitive skills by people of different general intellectual ability (Eysenck, 1986; Jensen, 1985) or age (Salthouse, 1982, 1985). The experiments on which this literature has been based suffer from methodological weaknesses, such that comparisons have only been made very early in practice and have only concerned mean latencies for correct responses. An experiment compared 90 volunteers aged from 50 through 79 years who were grouped in terms of their performance on the AH 4 (Heim, 1968) IQ test. It explored the joint and independent effects of individual differences in age and in IQ test score and the effects of practice on mean latencies (C RTs) on the shapes of distributions of correct and incorrect responses and on the limiting speeds with which accurate responses can be made (speed/error trade-off functions). We suggest that a plausible explanation for the results is that individual differences in age and in general ability influence C RTs mainly because they affect the efficiency with which responses can be controlled to maximize speed while maintaining accuracy.

Preschoolers' prosocial responses to their peers' distress.

Fifty-two preschoolers' (36 to 56 months old) spontaneous responses to their crying peers were naturalistically observed, recorded, and analyzed in 3 child-care programs. Individual differences in age, gender, temperament, social competence, child-care experience, and friendship status were examined to understand how these variables shape children's prosocial behavior with peers. Variations in manner of responding were related to children's temperament, friendship status, and positive interactive style with peers. The results suggest that socioemotional functioning with peers and individual characteristics affect children's responses to a peer's distress

Body-size dissatisfaction: Individual differences in age and gender, and relationship with self-esteem

This study investigated the effect of individual differences in age and gender on body-size dissatisfaction. Ss were presented with a set of nine silhouette drawings ranging from very thin to very fat. In an Australian replication of Fallon and Rozin ( Journal of Abnormal Psychology, 94, 102–105, 1985), young adult women rated their current figure as significantly larger than their ideal and attractive figures, whereas there was no difference in ratings for young adult men. However, in contrast to the finding of Rozin and Fallon ( Journal of Abnormal Psychology, 97, 342–345, 1988), the same pattern of gender differences emerged for mature women and men. Furthermore, only for the older women was body dissatisfaction correlated with self-esteem. It was suggested that body weight may carry different meaning for women of different ages.

Investigating models of human performance

In Decision and Stress, Broadbent (1971) highlighted the deficiencies of steady‐state information‐processing systems and recommended a methodology for studying change and individual variability in human performance. Some implications of his approach are considered here by reviewing studies of the ways in which performance in choice reaction time, visual search and simple memory tasks is affected by individual differences in age and intelligence, by alcohol and by practice. The results are discussed in terms of the successes and limitations of five types of model: (1) ‘box‐and‐arrow’ information flow models, (2) ‘control‐process’ models, (3) algebraic models of decision latencies, (4) ‘single‐factor’ models derived from psychometrics, and (5) connectionist‐network models.

Evidence of a correlation between wearing glasses and personality

Self-report personality correlates of wearing glasses were investigated. To control for possible effects of social stereotypes on self-reports of personality, judgements by strangers were also collected. The traits that perceivers inferred from spectacles differed from the self-reported traits that actually co-occurred with the presence of glasses. Thus a substantial influence of social stereotypes on self-reports of personality was not reasonable. Subjects who wore spectacles were less extraverted and less open to experience, even if individual differences in age and sex were partialled out. Two explanations of these findings are discussed: either visual acuity may co-occur with personality, or personality may influence the willingness to wear glasses.

Individual differences in aging: Behavioral and neurobiological correlates

The goal of this experiment was to determine the correlations among different behavioral and neurobiological measures in aged rats. Aged Sprague-Dawley rats were given a battery of cognitive and sensorimotor tests, followed by electrophysiological assessment of sleep and biochemical measurements of various neurotransmitter systems. The behavioral tests included the following: Activity level in an open field; short-term and long-term memory of a spatial environment as assessed by habituation: spatial navigation, discrimination reversal, and cue learning in the Morris water pool; spatial memory in a T-maze motivated by escape from water; spatial memory and reversal on the Barnes circular platform task; passive avoidance; motor skills. Sleep was assessed by electrographic cortical records. The following neurotransmitter markers were examined: Choline acetyltransferase; the density of nicotinic, benzodiazepine and glutamine receptors in the cortex and caudate nucleus; endogenous levels of norepinephrine, dopamine, and serotonin in the cortex and hippocampus. The duration of bouts of paradoxical sleep was strongly correlated with several cognitive measures and selected serotonergic markers. This finding suggests that changes in sleep patterns and brain biochemistry contribute directly to deficits in learning and memory, or that the same neurobiological defect contributes to age-related impairments in sleep and in learning and memory.

Gender differences in identity formation as a function of self-other relationships

Effects of differential male-female relational definitions of self on resolutions to the first six of Erikson's identity crises were examined in a sample of 388 adolescent males and females. Subject categorization of relational self-definitions was based on the Relational Self-Definition Scale. Resolutions to identity crises were measured by the Erikson Psychosocial Stage Inventory (EPSI). Predictions were drawn from theoretical notions related to Gilligan's view of distinctive male-female trends in self-other development and indicated that males with self-definitions separate from others and females with self-definitions connected with others would report higher degrees of positive resolutions on EPSI subscales compared to males with connected self-definitions and females with separate self-definitions. Results revealed that specific predictions were supported for resolutions to Trust, Initiative, and Intimacy crises independent of individual differences in age, educational level, vocabulary, and socioeconomic status of subjects. This suggests that gender differences in identity development may be linked to distinctive malefemale trends in the use of relational self-definitions consistent with Gilligan's views.

Behavioral feeding specialization in Pinaroloxias inornata , the “Darwin's Finch” of Cocos Island, Costa Rica

As a population, Cocos Finches exhibit a broad range of feeding behaviors spanning those of several families of birds on the mainland, while individuals feed as specialists year-round. Although this extreme intraspecific variability occurs as predicted in a tropical oceanic island environment, these specializations challenge contemporary ecological theory in that they are not attributable to individual differences in age, sex, gross morphology, or opportunistic exploitation of patchy resources. Instead, they appear to originate and be maintained behaviorally, possibly via observational learning. This phenomenon adds another direction to the evolutionary radiation of the Darwin's Finches and underscores the necessity for detailed behavioral and ecological studies at the individual level for understanding animal feeding systems and the causation of phenotypic variation.

Radiation exposure of the respiratory tract and associated carcinogenic risk due to inhaled radon daughters.

The atmospheric content of radon and its decay products contributes significantly to the radiation exposure of man even in the normal environment. In this study, the risk for lung cancer induction associated with normal exposure to natural radionuclides is assessed in Salzburg, Austria. Altogether more than a thousand rooms have been investigated by using combined radon grab-sampling methods together with continuous measurements of radon and daughters at different control stations. Dose calculations were carried out for 729 demoscopically selected test persons, considering individual differences in age, sex and life-style and atmospheric nuclide concentrations at different sites. Using a specially developed age-dependent lung model, the dose frequency distribution of the absorbed dose to the basal cells of the bronchial epithelium could be evaluated for the population of Salzburg. Dose modifications caused by anatomical and physiological variabilities as well as microdosimetric considerations of the stochastic events during energy deposition result in a significantly increased dispersion of the dose histogram. Induction of lung cancer due to inhalation of radon and decay products can be correlated with cumulative exposure based on experience with lung cancer incidence amongst uranium miners. Using the recommended range of lifetime risk values of 20-45 X 10(-5)/WLM (UN77), it is shown for Salzburg that about 15% of the observed number of lung cancer cases may be induced by natural radionuclides.

Radiation exposure and associated cancer risk due to radon and decay products

The atmospheric content of radon and its decay products, especially in buildings, represents a significant contribution to the radiation exposure of man even in a normal environment. A study in Salzburg-City/Austria over several years was carried out in over 1000 working-, living- and bedrooms. Dose calculations were performed for 729 test persons, considering individual differences in age, sex and life-style and atmospheric nuclide concentration at different sites.

Age, Housing Choice, and Neighborhood Age Structure

Prior studies of age segregation have been restricted to the use of aggregate data for blocks or census tracts, and to an aggregate assumption that the actual behavior of individuals was being observed. This study, however, focuses on the process whereby individual differences in age are transformed into age segregation; it does so through observation of the housing and location choices of individuals. A large sample of the population of all urbanized areas is used to test how persons of all ages fit into patterns of age segregation. In a path model, age is found related to neighborhood age structure, but its effects are considerable outweighed by those of housing and location choices. Elaboration of this general path model by age group shows that the individual model of age segregation operates least well among the elderly. Further exploration yields evidence that, among the elderly population, the traditional routes to age segregation have been replaced in recent years by an alternate process. It is suggested that the individual approach to age segregation would, if applied to other forms of segregation, advance knowledge of the phenomena.

Circadian rhythms in human performance

Circadian rhythms in performance exist for a wide range of tasks studied under laboratory conditions; they also occur in measures of efficiency obtained in real-life situations. The rhythms appear to be related to the daily cycle of sleep "need", and the largest negative variations in performance are normally observed when this need is greatest. The detailed forms of the circadian functions are influenced to some extent by individual differences in age and personality. However, task factors are of equal, if not greater, importance in determining the nature of a performance rhythm, since its basic phase is markedly different in cases involving memory. This latter finding raises the practical problem of job design in relation to time of day, and a taxonomic approach is suggested as the most fruitful way of arriving at the optimal solution for particular work situations requiring different abilities.

A STUDY OF THE RELATIONSHIP BETWEEN ABILITY, PERFORMANCE, ATTITUDES, INCLINATIONS AND SPEED OF PROGRESS USING INTRINSIC PROGRAMMED INSTRUCTION

Abstract The aim of the study was to establish the interrelationship amongst a variety of individual differences and performance when children were learning mathematics from intrinsic programmed instruction presented in teaching machines. In order to investigate the reliability of such inter‐relationships in different environments, a replicate rather than a large sample design was used. The sample consisted of six groups of children from four secondary schools (minimum N = 50). Various measures of intelligence, reading ability, personality trait, mathematical attainment, attitude and speed of progress were assessed and intercorrelated. Principal component analysis was done for each of the six groups. One of the components, usually the first, was one of maturation with high item correlations for age, intelligence, attainment, speed of progress, errors and gain in mathematical attainment measures. The children who most benefited from intrinsic programmed instruction were those who would most have benefited from conventional instruction. Attitude measures were found to be independent of maturational factors and were related to sex and personality traits. However, the major differences in component structure between samples suggested that reactions to, and achievement from, programmed instruction were more related to the way programmed instruction was organised in the various schools than to individual differences in age, intelligence and personality.

Marital Happiness of Parents and Their Children's Attitude to Marriage

PERSONS reared in present day urban America are exposed to a number of experiences which contribute to their conception of marriage, and influence their evaluation of marriage as a relatively desirable or undesirable status for themselves. Most of these experiences are vicarious: exposure to the representations of marriage in print, movies, the radio and television. Less vicarious is the learning of the risks of marital failure as epitomized by the divorce rate. But marriage is also very directly depicted and defined for the young by the marital relationship of their parents. It is in the home that they first and most continuously encounter marriage, not as a fiction or concept but as embodied in the behavior of their fathers and mothers with and toward one another. Apart from the picture of marriage which the child may build out of inferences from the parents' behavior one or both parents may wittingly attempt to indoctrinate the child with a conception of marriage as one of the great joys of adulthood or as a status to be warily approached if not altogether avoided. For the majority of the young, one of the probable major effects of their vicarious learning about marriage is that it is made to appear a highly attractive and desirable status. (And they lived happily ever after.) If this evaluation is not materially influenced by knowledge of the divorce rate it is still subject to some reality testing in that the child has intimate knowledge of the union of his parents, if of no other adults. To the extent that marriage as thus directly known is perceived as a highly satisfying experience the vicariously assimilated conception is reinforced or at least not contradicted. But insofar as the relationship of his parents is seen by the child as fraught with conflict and unhappiness his conception of marriage as a desirable goal may be challenged and his enthusiasm for marriage diminished.' Favorableness of attitude to marriage is a variable of theoretical interest for a number of reasons. It may be important in accounting for individual differences in age at marriage. It may be associated with individual differences and sex differences in patterns of courtship and mate selection. And it may be related to marital success. If, as hypothesized above, favorableness of attitude to marriage varies with parental happiness, the former may be one of the intervening variables in the oft-noted correla-tion between the marital happiness of parents and that of their offspring. The research reported below was concerned with testing the hypothesis of a positive association between the marital success of parents and the favorableness of their children's attitude to marriage. Since data were secured from men and women subjects it was also possible to test the widely-held assumption that in our society the unmarried female views marriage more favorably than does the male.