Faculty Bibliography

This study examines preadolescents' reports of risk-taking as predicted by two different, but related inhibitory control systems involving sensitivity to reward and loss on the one hand, and higher order processing in the context of cognitive conflict, known as executive functioning (EF), on the other. Importantly, this study examines these processes with a sample of inner-city, low-income preadolescents and as such examines the ways in which these processes may be related to risky behaviors as a function of children's levels of both concurrent and chronic exposure to household poverty. As part of a larger longitudinal study, 382 children (ages 9 -11) provided a self-report of risky behaviors and participated in the Iowa Gambling task, assessing bias for infrequent loss (preference for infrequent, high magnitude versus frequent, low magnitude loss) and the Hearts and Flowers task assessing executive functioning. Results demonstrated that a higher bias for infrequent loss was associated with higher risky behaviors for children who demonstrated lower EF. Furthermore, bias for infrequent loss was most strongly associated with higher risk-taking for children facing highest levels of poverty. Implications for early identification and prevention of risk-taking in inner-city preadolescents are discussed.

The relation of self-regulation measured prior to school entry to developing math and reading ability in prekindergarten through the second grade was examined in a prospective longitudinal sample of 1,292 children and families in predominantly rural and low-income communities in 2 regions of high poverty in the United States. Direct assessments of executive function, effortful control, and stress response physiology (indexed by resting levels of cortisol and alpha amylase obtained from saliva) were measured at child age 48 months and parents and teachers reported on children's effortful control using temperament rating scales at child age approximately 60 months. Math and reading ability, as measured by the Woodcock-Johnson III applied problems and letter-word subtests, respectively, were measured at prekindergarten through the second grade. Effects for self-regulation measures were seen primarily for initial level and to some extent growth in both mathematics and reading, even when controlling for family demographic characteristics that represent relevant selection factors into higher levels of both self-regulation and academic achievement. These effects persisted for mathematics but not for reading with the inclusion of child cognitive abilities, vocabulary, and speed of processing measured in prekindergarten, concurrent with the first time point for the academic measures. Results are interpreted as indicating a role for self-regulation in learning ability generally, likely through support for attention and reasoning abilities that are most specific to the assessment of mathematics in this analysis. Implications for instruction and for assessment and the best ways to support the development of early math and reading ability for children at risk for school failure are discussed.

Physiological responses to threat occur through both the autonomic nervous system (ANS) and the hypothalamic pituitary adrenal (HPA) axis. Activity in these systems can be measured through salivary alpha-amylase (sAA) and salivary cortisol, respectively. Theoretical work and empirical studies have suggested the importance of examining the coordination of these systems in relation to cognitive functioning and behavior problems. Less is known, however, about whether these systems interactively predict more automatic aspects of attention processing such as attention toward emotionally salient threatening stimuli. We used a dot probe task to assess attention bias toward threatening stimuli in 347 kindergarten children. Cortisol and sAA were assayed from saliva samples collected prior to children's participation in assessments on a subsequent day. Using regression analyses, we examined relations of sAA and cortisol to attention bias. Results indicate that cortisol and sAA interact in predicting attention bias. Higher levels of cortisol predicted greater bias toward threat for children who had high levels of sAA, but predicted greater bias away from threat for children who had low levels of sAA. These results suggest that greater symmetry in HPA and ANS functioning is associated with greater reliance on automatic attention processes in the face of threat.

Several studies have investigated associations between socioeconomic status (SES) and indicators of children's physiological and cognitive self-regulation. Although objective measures of family SES may be good proxies for families' experiences of disadvantage, less is known about subjective aspects of families' experiences. We hypothesize that subjective social status (SSS) and perceived stress may be important independent predictors of children's stress physiology and executive functioning (EF). Eighty-two children from diverse SES backgrounds were administered EF measures and provided saliva samples for cortisol assay. Caregivers reported on objective SES, SSS, and perceived stress. Results suggest that SES and SSS are both independently and positively related to EF. In models predicting stress physiology, higher perceived stress was associated with lower baseline cortisol. Moreover, SES and age interacted to predict cortisol levels such that among younger children, lower SES was associated with higher cortisol, whereas among older children, lower SES was associated with lower cortisol. Results highlight the importance of considering both objective and subjective indicators of families' SES and stressful experiences in relation to multiple aspects of children's self-regulation.

Emotionally arousing stimuli have been largely unsuccessful in eliciting cortisol responses in young children. Whether or not emotion challenge will elicit a cortisol response, however, may in part be determined by the extent to which the tasks elicit behavioral reactivity and regulation. We examined relations of behavioral reactivity and regulation to emotional arousal in the context of fear and frustration to the cortisol response at 7, 15, and 24 months of age in a low income, rural population based sample of 1,292 families followed longitudinally from birth. At each age, children participated in fear and frustration inducing tasks, and cortisol samples were taken at three time points (before the tasks began, 20 min following peak emotional arousal or after the series of tasks ended, and 40 min after peak arousal or the tasks ended) in order to capture both increases (reactivity) and subsequent decreases (regulation) in the cortisol response. Using multilevel models, we predicted the cortisol response from measures of behavioral reactivity and regulation. At 7 months of age, cortisol reactivity and recovery were related to behavioral reactivity during a frustration-eliciting task and marginally related to behavioral reactivity during a fear-eliciting task. At 15 and 24 months of age, however, cortisol reactivity and recovery were related only to behavioral reactivity during a fear-eliciting task. Results indicate that while behavioral reactivity is predictive of whether or not infants and young children will exhibit a cortisol response to emotionally arousing tasks, behavioral and cortisol reactivity are not necessarily coupled.

Intervention studies indicate that children's childcare experiences can be leveraged to support the development of executive functioning (EF). The role of more normative childcare experiences is less clear. Increasingly, theory and empirical work suggest that individual differences in children's physiological stress systems may be associated with meaningful differences in the way they experience these early environments. Using data from a large population-based sample of predominantly low-income rural families, we tested the degree to which children's childcare experiences--quantity, quality, and type--in the first 3 years of life predicted emerging EF. Moreover, we examined whether these effects varied as a function of children's basal cortisol levels in infancy and toddlerhood--an indicator of hypothalamic pituitary adrenal (HPA) axis stress physiology. Our results showed that higher quality care predicted more effective EF at 48 months, irrespective of quantity or type. This relation did not vary as a function of children's early cortisol levels. Attending greater hours of care per week was also related to EF; however--consistent with theory--the positive association between spending more time in childcare and more positive EF extended only to children with low levels of basal cortisol at 7 or 24 months of age. Attending center-based care was unassociated with EF.

A considerable body of literature suggests that children's child-care experiences may impact adrenocortical functioning in early childhood. Yet emerging findings also suggest that the magnitude and sometimes the direction of child-care effects on development may be markedly different for children from higher risk contexts. Using data from a large population-based sample of families from predominantly low-income backgrounds in rural communities, we tested the degree to which links between children's child-care experiences (at 7-36 months) and their subsequent cortisol levels (at 48 months) were moderated by their level of cumulative environmental risk. Our results provided evidence of a crossover interaction between cumulative risk and child-care quantity. For children from low-risk contexts, greater weekly hours in child care were predictive of higher cortisol levels. In contrast, for children facing several cumulative risk factors, greater hours in child care per week were predictive of lower cortisol levels. These effects were robust after adjusting for several controls, including children's cortisol levels in early infancy. Child-care quality and type were not predictive of children's cortisol levels, and neither mitigated the conditional effect of child-care quantity on cortisol. These findings suggest that links between child care and children's development may differ as a function of children's broader ecologies.

Prior research with adults suggests mixed evidence for the relations of state and trait anxiety to prefrontal executive functions (EF). Trait anxiety is hypothesised to impair the efficiency of prefrontal areas and goal-directed attention and has been largely associated with poorer performance on executive functioning tasks. Fewer studies have investigated state anxiety, and the findings have been mixed. As studies of these processes in children have been limited by small sample sizes and a focus on working memory, we examine whether state and trait anxiety are associated with performance on two EF tasks in a sample of urban, low-income children, ages 9-12. Results indicated that higher trait anxiety predicted lower executive functioning on both tasks. In addition, higher state anxiety was related to better performance on the Stroop task. Results demonstrate that, consistent with the adult literature, higher trait anxiety is related to lower executive functioning in children.

The relation of observed emotional reactivity and regulation in infancy to executive function in early childhood was examined in a prospective longitudinal sample of 1,292 children from predominantly low-income and rural communities. Children participated in a fear eliciting task at ages 7, 15, and 24 months and completed an executive function battery at age 48 months. Results indicated that the relation of child negative emotional reactivity at 15 months of age to executive functioning at 48 months of age was dependent on observed emotion regulation. High levels of executive function ability were observed among children who exhibited high levels of emotional reactivity and high levels of the regulation of this reactivity. In contrast, low levels of executive function ability were observed among children who exhibited high levels of reactivity but low levels of regulation. Among children exhibiting low levels of emotional reactivity, emotion regulation was unrelated to executive functioning. Moreover, emotionally reactive infants exhibiting high levels of emotion regulation were more likely to have primary caregivers who exhibited high levels of positive parenting behavior in a parent-child interaction task. Results provide support for a neurobiologically informed developmental model in which the regulation of emotional arousal is one mechanism whereby supportive environments are associated with higher levels of self-regulation ability for highly reactive infants. Findings are discussed with implications for differential susceptibility and biological sensitivity theories of child by context interaction.

Recent studies have demonstrated alterations in the cortisol awakening response (CAR) and brain abnormalities in adults with obesity and type 2 diabetes mellitus (T2DM). While adolescents with T2DM exhibit similar brain abnormalities, less is known about whether brain impairments and hypothalamic-pituitary-adrenal (HPA) axis abnormalities are already present in adolescents with pre-diabetic conditions such as insulin resistance (IR). This study included 33 adolescents with IR and 20 without IR. Adolescents with IR had a blunted CAR, smaller hippocampal volumes, and greater frontal lobe atrophy compared to controls. Mediation analyses indicated pathways whereby a smaller CAR was associated with higher BMI which was in turn associated with fasting insulin levels, which in turn was related to smaller hippocampal volume and greater frontal lobe atrophy. While we had hypothesized that HPA dysregulation may result from brain abnormalities, our findings suggest that HPA dysregulation may also impact brain structures through associations with metabolic abnormalities.