Changes and challenges in 20 years of research into the development of executive functions

This review of 20 years of developmental research on Executive Functions (EF) offers a broad‐brushstroke picture that touches on multiple issues including: (i) findings from typical and atypical groups, from infancy to adolescence; (ii) advances in assessment tools and in statistical analysis; (iii) the interplay between EF and other cognitive systems (e.g. those involved in children's developing understanding of mind, and in their processing of reward signals); (iv) integration of cognitive and neuroscience perspectives on EF; and (v) environmental factors that have either a positive influence (e.g. training/intervention programmes; parental scaffolding) or a negative influence (e.g. maltreatment, neglect, traumatic brain injury) on EF. Of the several themes to emerge from this review, two are particularly important; these concern the need to adopt developmental perspectives and the potential importance for intervention work of research on social influences on EF. Specifically, the review highlights both developmental continuities (e.g. in the correlates of EF) and contrasts (e.g. in the nature of EF and its neural substrates) and calls for research that compares developmental trajectories for EF in different groups (e.g. children with autism versus ADHD). In addition, findings from both family‐based research and randomized controlled trials of school‐based interventions highlight the importance of environmental influences on EF and so support the development of interventions to promote EF and hence improve children's academic and social outcomes. Copyright © 2011 John Wiley & Sons, Ltd.     

Media exposure, internalization of the thin ideal, and body dissatisfaction: comparing Asian American and European American college females

Internalization of the thin ideal mediates the media exposure-body dissatisfaction relation in young adult European American females. There is little related research on Asian Americans. We used structural equations modeling to test: (1) whether media exposure was associated with body dissatisfaction in Asian American young adult females, (2) internalization of the thin ideal mediated any such association, and (3) whether the mediational model provided equivalent fit for European American and Asian American samples. Participants were 287 college females (154 Asian Americans, 133 European Americans). Internalization of the thin ideal explained the media exposure-body dissatisfaction association equally well for both groups. Results suggest that Asian Americans may be employing unhealthy weight control behaviors, and may be prone to developing eating disorders, at rates similar to European American young adult females. Clinicians need to screen carefully for body dissatisfaction, unhealthy weight control behaviors, and eating disorders in Asian American females.     

Human performance on negative slope schedules of points exchangeable for money: a failure of molar maximization

Panel pressing was generated and maintained in 5 adult humans by schedules of points exchangeable for money. Following exposure to a variable-interval 30-s schedule and to a linear variable-interval 30-s schedule (which permitted points to accumulate in an unseen "store" in the absence of responding), subjects were exposed to a series of conditions with a point-subtraction contingency arranged conjointly with the linear variable-interval schedule. Specifically, points were added to the store according to the linear-variable interval 30-s schedule and were subtracted from the store according to a ratio schedule. Ratio value varied across conditions and was determined individually for each subject such that the subtraction contingency would result in an approximately 50% reduction in the rate of point delivery. Conditions that included the subtraction contingency were termed negative slope schedules because the feedback functions were negatively sloped across all response rates greater than the inverse of the variable-interval schedule, in this case, two per minute. Overall response rates varied inversely with the subtraction ratio, indicating sensitivity to the negative slope conditions, but were in excess of that required by accounts based on strict maximization of overall reinforcement rate. Performance was also not well described by a matching-based account. Detailed analyses of response patterning revealed a consistent two-state pattern in which bursts of high-rate responding alternated with periods of prolonged pausing, perhaps reflecting the joint influence of local and overall reinforcement rates.     

The Efficacy, Safety, and Practicality of Treatments for Adolescents with Attention-Deficit/Hyperactivity Disorder (ADHD)

Studies examining interventions for adolescents diagnosed with attention-deficit/hyperactivity disorder (ADHD) were reviewed to evaluate their efficacy. These efficacy findings were supplemented with a preliminary system for judging safety and practicality. Results suggest that the stimulant drug methylphenidate (MPH) is safe and well-established empirically, but has some problems with inconvenience and noncompliance. Preliminary research supports the efficacy, safety, and practicality of some psychotherapeutic interventions, including behavioral classroom interventions, note-taking training, and family therapy. Treatment with tricyclic antidepressants was judged to have minimal empirical support and debatable safety. Very little is known about long-term effectiveness of treatments, long-term compliance, or multimodal treatments for adolescents such as stimulants plus behavior therapy.     

Animal foraging and the evolution of goal-directed cognition

Foraging- and feeding-related behaviors across eumetazoans share similar molecular mechanisms, suggesting the early evolution of an optimal foraging behavior called area-restricted search (ARS), involving mechanisms of dopamine and glutamate in the modulation of behavioral focus. Similar mechanisms in the vertebrate basal ganglia control motor behavior and cognition and reveal an evolutionary progression toward increasing internal connections between prefrontal cortex and striatum in moving from amphibian to primate. The basal ganglia in higher vertebrates show the ability to transfer dopaminergic activity from unconditioned stimuli to conditioned stimuli. The evolutionary role of dopamine in the modulation of goal-directed behavior and cognition is further supported by pathologies of human goal-directed cognition, which have motor and cognitive dysfunction and organize themselves, with respect to dopaminergic activity, along the gradient described by ARS, from perseverative to unfocused. The evidence strongly supports the evolution of goal-directed cognition out of mechanisms initially in control of spatial foraging but, through increasing cortical connections, eventually used to forage for information.     

Distance,Contact, and Intergenerational Relationships: Grandparents and Adult Grandchildren from an International Perspective

In previous studies of intergenerational relationships, geographic distance has been considered the most obvious factor influencing opportunity for frequency of contact between grandparents and grandchildren. This study presents findings from a survey of 70 international college students in the Unites States regarding perceived grandparental influence and relationship satisfaction with their “closest” grandparent. Results showed that participants' perceived influence of grandparents and relationship satisfaction was maintained despite decreased contact between grandparents and grandchildren. In addition, grandchildren who initiated contact were found to have a significant impact on relationship satisfaction. This study provides an understanding of distance, contact, and intergenerational relationships in an international context.     

Verbal fluency over time as a measure of automatic and controlled processing in children with ADHD

The performance of ADHD children on semantic category fluency (SCF) versus initial letter fluency (ILF) tasks was examined. For each participant, word production was recorded for each 15-s time slice on each task. Performance on both fluency tasks was compared to test the hypothesis that children with ADHD are characterized by a performance deficit on the ILF task because performance on this task is less automated than performance on the SCF. Children classified with ADHD (N = 20) were compared to children with other psychopathology (N = 118) and healthy controls (N = 130). Results indicated that the groups could not be differentiated by the total number of words produced in 60 s in either fluency task. As hypothesized, a significant interaction of group by productivity over time by type of fluency task was found: ADHD children had more problems finding words in the first 15 s of the IFL than did children in the other two groups, and as compared with their performance on the SCF. Results were taken to indicate that children with ADHD symptoms show a delay in the development of automating skills for processing abstract verbal information.     

Evidence for an Error Monitoring Deficit in Attention Deficit Hyperactivity Disorder

We studied error monitoring in ADHD and control children in a task requiring inhibition of a motor response. The extent of slowing following successful (stopped) and failed (nonstopped) inhibition was compared across groups. We also measured the time required to inhibit a response (stop signal reaction time, SSRT). Compared to controls, ADHD participants slowed less following nonstopped responses. Slowing did not vary with comorbid reading, oppositional, conduct or anxiety disorder, sex or ADHD subtype. Slowing after nonstopped responses was marginally, although significantly correlated with total ADHD symptoms and with age. ADHD participants had significantly longer SSRT than controls, but SSRT was not significantly correlated with slowing. The apparent deficit in error monitoring in ADHD and its independence from the inhibition deficit observed in ADHD has implications for executive control models of ADHD, performance problems associated with the disorder and for component theories of executive control.     

Career Centered High School Education and Post–High School Career Adaptation

This study examines the quality of the transition into employment roles among a socioeconomically diverse cohort of 1,143 high school seniors who were interviewed as seniors in 1998 and 2 years later. Focusing on both subjective and objective dimensions of work adaptation, analyses examine differences in these outcomes associated with taking a high school career-major versus a more traditional academic program. This type of major is intended to assist in the career development and economic adaptation of more disadvantaged young adults and follows from an ecological model emphasizing the importance of connections between educational and employment institutions in the socialization of young people. Results indicate small but significant effects of having the career-major for the perceptual variables. Group differences were not found for the variables assessing more objective qualities of their jobs. The discrepancy between subjective and objective outcomes may suggest a short-term psychological optimism in the absence of an objective situation that would justify this view. Discussion centers on the need for stronger institutional support for school-work connections.