Continuity in intellectual functioning: the role of self-reported health

Surviving members of the Berkeley Older Generation Study were interviewed and tested with the Wechsler Adult Intelligence Scale in 1969-1970 and again in 1983-1984, when subjects' ages ranged from 73 to 93. Health was assessed by self-reports at both measurement periods. Although many individuals showed some decline in intellectual functioning, substantial individual differences were apparent at all age levels. More than one half of the subjects showed no reliable change, and a minority showed a reliable increase in verbal scores. The role of self-reported health has increasing importance in the maintenance of intellectual functioning in advanced old age.     

The involvement of executive functions in prospective memory performance of adults

The present study examines the relationship between prospective memory performance and executive functioning. The four phases of the prospective memory process—intention formation, intention retention, reinstantiation of the intention, and intention execution—are assumed to require different amounts of executive processing, most of which is demanded in the phases of intention formation and intention execution. At present, though, it is still unclear whether, and to what extent, prefrontal executive systems are involved in different kinds of prospective memory tasks, as some findings suggest that prospective memory might rather rely on nonstrategic processes that are unlikely to depend on prefrontal executive systems. Therefore, this study focuses on the following questions: (1) to what degree does executive functioning predict prospective memory performance in different standard prospective memory tasks and, furthermore, are certain executive measures better predictors than others; (2) are age‐related effects in different prospective memory measures due to individual differences in executive functioning; and (3) do age‐related differences in prospective memory exist that are not explained by individual differences in executive functioning. In a sample of 80 adults (20‐80 years), we applied four instruments to measure prospective memory: a traditional single‐task paradigm, two more complex tasks—one time‐based and one event‐based—and a highly complex multi‐task paradigm. We further assessed a broadly defined construct of executive functioning using several standard neuropsychological tests. Results showed that executive functioning did not predict performance in the simple single‐task paradigm. However, executive functioning, but not age, predicted performance in the two more complex standard tests of prospective remembering, and both executive functioning and age predicted performance in the most complex paradigm. In sum, the obtained data underline the assumption that frontal/ executive functions are related to prospective memory performance across a range of prospective paradigms. It also seems clear that age differences in prospective memory performance partially depend on age‐related individual differences in frontal/executive functions.     

The Essential Child. Susan Gelman. New York: Oxford University Press. 2003. 392 pages, $49.95 (US), cloth or paper.

To evaluate the claim that correct performance on unexpected transfer false-belief tasks specifically involves mental-state understanding, two experiments were carried out with children with autism, intellectual disabilities, and typical development. In both experiments, children were given a standard unexpected transfer false-belief task and a mental-state-free, mechanical analogue task in which participants had to predict the destination of a train based on true or false signal information. In both experiments, performance on the mechanical task was found to correlate with that on the false-belief task for all groups of children. Logistic regression showed that performance on the mechanical analogue significantly predicted performance on the false-belief task even after accounting for the effects of verbal mental age. The findings are discussed in relation to possible common mechanisms underlying correct performance on the two tasks.     

Age differences in reaction time and attention in a national telephone sample of adults: education, sex, and task complexity matter

This study demonstrated effects of age, education, and sex on complex reaction time in a large national sample (N = 3,616) with a wide range in age (32-85) and education. Participants completed speeded auditory tasks (from the MIDUS [Midlife in the U.S.] Stop and Go Switch Task) by telephone. Complexity ranged from a simple repeated task to an alternating task that involved central executive processes including attention switching and inhibitory control. Increased complexity was associated with slower responses in older adults, those with lower education, and women, even after controlling for differences in health status. Higher levels of education were associated with greater central executive efficiency across adulthood: Overall, adults with college degrees performed on complex tasks like less educated individuals who were 10 years younger, up to age 75. These findings suggest that advanced education can moderate age differences on complex speeded tasks that require central executive processes, at least up to the point in old age at which biological declines predominate. The approach demonstrates the utility of combining laboratory paradigms with survey methods to enable the study of larger, more diverse and representative samples across the lifespan.     

Executive function in children with high and low attentional skills: Correspondences between behavioural and cognitive profiles

Cognitive performance was compared between two groups of typically developing children, who had been observed and rated as differing significantly in their attentional skills at school. The participants were 24 8‐ and 9‐year‐old children scoring poorly relative to peers, on a classroom observation scale and teacher rating scale for attention, hyperactivity, and impulsivity [low‐attentional skills (LAS) group] and 24 sex‐ and age‐matched children scoring at a high level compared to peers [high‐attentional skills (HAS) group]. The two groups were compared on a series of cognitive tasks to assess executive function (EF). The LAS group performed within the typical range yet at a significantly lower level than the HAS group on the majority of the EF tasks administered, namely working memory and inhibition measures, even though there were no significant differences between the groups on a measure of intellectual ability. Working memory measures followed by measures of inhibition emerged as the best predictors of group membership. These findings provide empirical evidence that there are individual differences in attentional skills. Specifically, that there is a relationship between behavioural inattention, hyperactivity, and impulsivity and cognitive performance on working memory and inhibitory control tasks.     

Impaired performance from brief social isolation of rhesus monkeys (Macaca mulatta): a multiple video-task assessment

Social isolation has been demonstrated to produce profound and lasting psychological effects in young primates. In the present investigation, two adult rhesus monkeys (Macaca mulatta) were isolated from one another for up to 6 days and tested on 7 video tasks designed to assess psychomotor and cognitive functioning. Both the number and the quality (i.e., speed and accuracy) of responses were significantly compromised in the social isolation condition relative to levels in which the animals were tested together. It is argued that adult rhesus are susceptible to performance disruption by even relatively brief social isolation, and that these effects can best be assessed by a battery of complex and sensitive measures.     

Cerebellar tasks do not distinguish between children with developmental dyslexia and children with intellectual disability.

This paper explored the claim that only children with developmental dyslexia, whose reading ability is discrepant from their average general reasoning ability show specific deficits in motor tasks assessing cerebellar functioning (Fawcett et al., 2001, Cerebellar tests differentiate between groups of poor readers with and without IQ discrepancy. J. Learning Disabilities, 34, 119) and rapid serial naming (RAN, Wolf & Bowers, 1999, The double deficit hypothesis for the developmental dyslexias. J. Educ. Psychol., 91, 1). All available children between the ages of 11 and 14 were recruited from two special schools for children with either (a) formally-diagnosed intellectual disabilities (N = 18); or (b) formal diagnoses of developmental dyslexia (N = 25). These two groups of children did not differ on gender, age, pseudoword decoding abilities, or on 7 of 8 literacy measures, but did differ significantly, as expected on verbal and non-verbal reasoning tasks. Importantly, there were no deficits in bead threading ability or postural stability in the children with developmental dyslexia compared to the children with intellectual disabilities. There were also no between-group differences in rapid naming measures. The present results therefore provide no support for the claim that cerebellar deficits or RAN distinguish between children with dyslexia and children with intellectual disabilities that include reading.     

Intellectual and cognitive profiles in patients affected by schizophrenia

Intellectual abilities display high heterogeneity in patients with schizophrenia that might depend on the interaction among neurodevelopmental processes, environmental factors and neurocognitive decline. This study aimed to disentangle the interplay between intellectual level, cognitive status and each cognitive domain, with a focus on speed-related abilities, also including pre-morbid factors. In details, by means of cluster analysis, we identified both in global sample of 452 patients affected by schizophrenia and in a subsample with high pre-morbid functioning, different profiles based on current intellectual level and global cognitive status, analysing the distribution of deficits in each cognitive domains between groups. Then, through regression models, we analysed the contribution of speed-related domains and global cognitive profile to each other cognitive function. Considering the whole sample, results highlight three groups (high, medium and low cognitive level), while among patients with high pre-morbid level, the heterogeneity was best captured by two groups (high and medium level). Still, within each group, a small to high percentage of patients achieved normal score in neurocognitive abilities depending on the cluster they belong to. Speed of processing and psychomotor coordination resulted impaired in all clusters, even in patients with high pre-morbid functioning. The regression analyses revealed significant effects of both cognitive profile and speed-dependent domains on the other cognitive abilities. This study confirms, in a large sample, previous data about the heterogeneity of intellectual and neurocognitive functioning in schizophrenia and highlights the main role of speed-dependent neurocognitive functioning, also as an important target of rehabilitation.     

NEUROBEHAVIORAL SEQUELAE OF CHILD SEXUAL ABUSE

This study examined intellectual and memory functioning in a sample of sexually abused children compared to demographically and age-matched controls. The severity of abuse and other pertinent factors were also examined in relation to cognitive performance. Elevated levels of psychopathology were present in the abused children, as well as diminished performance on tasks influenced by attention/concentration. However, after controlling for differences in IQ and socioeconomic status (SES), significant differences in memory function were not found. Results are discussed in the context of stress effects on cognition and the potential resiliency of cognitive function in children undergoing treatment for sexual abuse.     

Neurobehavioral sequelae of child sexual abuse.

This study examined intellectual and memory functioning in a sample of sexually abused children compared to demographically and age-matched controls. The severity of abuse and other pertinent factors were also examined in relation to cognitive performance. Elevated levels of psychopathology were present in the abused children, as well as diminished performance on tasks influenced by attention/concentration. However, after controlling for differences in IQ and socioeconomic status (SES), significant differences in memory function were not found. Results are discussed in the context of stress effects on cognition and the potential resiliency of cognitive function in children undergoing treatment for sexual abuse.     

Relating children's attentional capabilities to intelligence, memory, and academic achievement: a test of construct specificity in children with asthma.

The relationship between attention, intelligence, memory, achievement, and behavior in a large population (N = 939) of children without neuropsychologic problems was investigated in children with mild and moderate asthma. It was hypothesized that different levels of children's attentional capabilities would be associated with different levels of intellectual, memory, and academic abilities. Children ages 6-12 at the eight clinical centers of the Childhood Asthma Management Program (CAMP) were enrolled in this study. Standardized measures of child neuropsychological and behavioral performance were administered to all participants, with analyses examining both the developmental trajectory of child attentional capabilities and the associations between Continuous Performance Test (CPT) scores and intellectual functioning, and measures of memory, academic achievement, and behavioral functioning. Findings demonstrated that correct responses on the CPT increase significantly with age, while commission errors decrease significantly with age. Performance levels on the CPT were associated with differences in child intellectual function, memory, and academic achievement. Overall these findings reveal how impairments in child attention skills were associated with normal levels of performance on measures of children's intelligence, memory, academic achievement, and behavioral functioning, suggesting that CPT performance is a salient marker of brain function.     

Neuropsychological performance of emotionally disturbed students on the LNNB and LNNB-C

A number of researchers have reported an association between neuropsychological impairment and psychiatric disorders. However, there has been relatively little research on the neuropsychological functioning of emotionally disturbed students served in public schools. The purpose of this study was to determine the neuropsychological performance of 65 emotionally disturbed students 8–18 years old on the Luria-Nebraska Neuropsychological Battery: Form I (LNNB) and the Luria-Nebraska Neuropsychological Battery: Children's Revision (LNNB-C). The results indicated that approximately 42% of the younger group (99–154 months) and 38% of the older group (156– 226 months) demonstrated neuropsychological impairment as defined by criterion values for the various scales of the two batteries. On average, the emotionally disturbed students appeared to demonstrate more difficulty on more complex cognitive tasks, such as writing, arithmetic, and intellectual processes, than for less complex tasks, such as motor functions.     

Perceptual, cognitive and linguistic development after early hemispherectomy: two case studies.

Longitudinal data on perceptual-motor, cognitive, and linguistic functioning is reported for two children: one with right hemispherectomy and one with left hemispherectomy. Both levels of functioning and specific profiles of abilities within an area of function are evaluated. The subjects both show effects from damage to the brain: shortened memory span, general perceptual and motor disabilities, and somewhat depressed general intellectual functioning. Areas of comparative strength and weakness in functioning in the two subjects are suggestive of adult patterns of hemispheric specialization, despite the young age of the subjects at the time of brain damage.     

The continuing effects of substantively complex work on the intellectual functioning of older workers.

Using a nationally representative sample of employed men and women in this longitudinal study, the authors extended for another 20 years findings based on 1964 and 1974 data (Kohn & Schooler, 1983) that substantively complex work improves intellectual functioning. This study provides evidence that intellectual functioning and substantive complexity of work continue to reciprocally affect each other. In addition, it shows that the intellectual flexibility measure used earlier (Kohn & Schooler, 1978, 1983) is highly correlated with more standard measures of intellectual functioning. Most importantly, it shows that, although substantively complex work significantly increased the level of intellectual functioning of both the younger and older halves of the sample, the effect is significantly greater among the older workers.     

Effects of traumatic stress and perceived stress on everyday cognitive functioning

Stressful or traumatic events have been shown to impair cognitive functioning on laboratory-based tasks due to stress-related intrusive thoughts and avoidance. However, research on the effects of stress on everyday cognitive functioning has been lacking. A sample of 909 undergraduates completed measures of perceived stress, PTSD symptoms, and everyday cognitive failures. The results revealed that both perceived stress and PTSD symptoms uniquely predicted cognitive failures, even after controlling for a number of potentially confounding variables. Additionally, there was a significant interaction. Participants with low scores on both measures of stress reported the fewest occurrences of everyday cognitive failures. In contrast, participants with elevated scores on either measure of stress reported higher levels of cognitive failures. These results suggest that there are unique negative effects of perceived stress and PTSD symptoms on everyday cognitive functioning and sharpen our understanding of the relationship between stress and cognition.     

Effects of traumatic stress and perceived stress on everyday cognitive functioning

Stressful or traumatic events have been shown to impair cognitive functioning on laboratory-based tasks due to stress-related intrusive thoughts and avoidance. However, research on the effects of stress on everyday cognitive functioning has been lacking. A sample of 909 undergraduates completed measures of perceived stress, PTSD symptoms, and everyday cognitive failures. The results revealed that both perceived stress and PTSD symptoms uniquely predicted cognitive failures, even after controlling for a number of potentially confounding variables. Additionally, there was a significant interaction. Participants with low scores on both measures of stress reported the fewest occurrences of everyday cognitive failures. In contrast, participants with elevated scores on either measure of stress reported higher levels of cognitive failures. These results suggest that there are unique negative effects of perceived stress and PTSD symptoms on everyday cognitive functioning and sharpen our understanding of the relationship between stress and cognition.     

Efficiency of route selection as a function of adult age

Two tasks hypothesized to assess the efficiency of route selection were administered to 328 adults ranging from 18 to 93 years of age. Increased age was associated with slower completion of mazes, even after adjusting for differences in perceptual-motor speed, and with longer and less accurate routes in a task in which participants were asked to visit designated exhibits in a zoo. The route selection measures were correlated with measures hypothesized to represent executive functioning, such as the number of categories in the Wisconsin card sorting test and the number of words generated in a category fluency test. However, most of the age-related influences on the measures from the route selection tasks were shared with age-related effects on established cognitive abilities, which implies that the same mechanisms may account for the relations of age on both sets of variables.     

The influence of professional expertise and task complexity upon the potency of the contextual interference effect

The contextual interference (CI) effect has been investigated through practice schedule manipulations within both basic and applied studies. Despite extensive research activity there is little conclusive evidence regarding the optimal practice structure of real world manipulative tasks in professional training settings. The present study therefore assessed the efficacy of practising simple and complex knot-tying skills in professional fire-fighters training. Forty-eight participants were quasi-randomly assigned to various practice schedules along the CI continuum. Twenty-four participants were students selected for their novice knot-tying capabilities and 24 were experienced fire-fighters who were more 'experienced knot-tiers'. They were assessed for skill acquisition, retention and transfer effects having practiced tying knots classified as simple or complex. Surprisingly, high levels of CI scheduling enhance learning for novices even when practising a complex task. The findings also revealed that CI benefits are most apparent as learners engage in tasks high in transfer distality. In conclusion, complexity and experience are mediating factors influencing the potency of the CI training effect in real-world settings.     

Cognitive functioning,personality variables and academic achievement of hemophilic and normal children: A comparative study

The present study was conceptualized in the context of the psychosocial needs of Hemophilic children and adolescents of Kolkata. Twenty four Hemophilic children and adolescents were compared with a matched group of normal controls to find out any specific difference in terms of visuomotor gestalt functioning, intellectual level, academic achievement and personality dimensions. Academic achievement was assessed by averaging the results of the last three consecutive school examinations. Intellectual functioning was assessed by Progressive Matrices by Raven, and personality dimensions were assessed by Junior Eysenck Personality Questionnaire. Chi square tests and ANOVA were conducted to determine whether the Hemophilic children differed significantly from the normal controls across age levels. Findings revealed that there was little difference between the two groups in terms of intellectual level, and most dimensions of personality, although the Hemophilics fared worse than normals in neuropsychological, social and academic aspects. Implication for intervention is discussed.     

Motor and cognitive control in a normative sample of 7‐year‐olds

The aim of the present study was to explore the relationship between cognitive and motor control by correlating individual performance on a variety of complex tasks in a normative sample of over 100 7‐year‐olds. While there are a few studies including children with specific developmental disorders (i.e. ADHD and DCD) showing that they share similar comorbid deficits, it is still unclear whether control processes share variance in normative samples. Results presented here reveal on the one hand that some aspects of cognitive and motor control are significantly interrelated, even when controlling for age. On the other hand, individuals’ ability to efficiently respond to the speed and accuracy demands of any of the included tasks appeared to constitute an important aspect of executive functioning.