Kristin A. Buss

Stress reactivity and attachment security

Seventy-three 18-month-olds were tested in the Ainsworth Strange Situation. These children were a subset of 83 infants tested at 2, 4, 6, and 15 months during their well-baby examinations with inoculations. Salivary cortisol, behavioral distress, and maternal responsiveness measures obtained during these clinic visits were examined in relation to attachment classifications. In addition, parental report measures of the childrens social fearfulness in the 2nd year of life were used to classify the children into high-fearful versus average- to low-fearful groups. In the 2nd year, the combination of high fearfulness and insecure versus secure attachment was associated with higher cortisol responses to both the clinic exam-inoculation situation and the Strange Situation. Thus, attachment security moderates the physiological consequences of fearful, inhibited temperament. Regarding the 2-, 4-, and 6-month data, later attachment security was related to greater maternal responsiveness and lower cortisol baselines. Neither cortisol nor behavioral reactivity to the inoculations predicted later attachment classifications. There was some suggestion, however, that at their 2-month checkup, infants who would later be classified as insecurely attached exhibited larger dissociations between the magnitude of their behavioral and hormonal response to the inoculations. Greater differences between internal (hormonal) and external (crying) responses were also negatively correlated with maternal responsiveness and positively correlated with pretest cortisol levels during these early months of life.

Right Frontal Brain Activity, Cortisol, and Withdrawal Behavior in 6-Month-Old Infants

Although several studies have examined anterior asymmetric brain electrical activity and cortisol in infants, children, and adults, the direct association between asymmetry and cortisol has not systematically been reported. In nonhuman primates, greater relative right anterior activation has been associated with higher cortisol levels. The current study examines the relation between frontal electroencephalographic (EEG) asymmetry and cortisol (basal and reactive) and withdrawal-related behaviors (fear and sadness) in 6-month-old infants. As predicted, the authors found that higher basal and reactive cortisol levels were associated with extreme right EEG asymmetry. EEG during the withdrawal-negative affect task was associated with fear and sadness behaviors. Results are interpreted in the context of the previous primate work, and some putative mechanisms are discussed.

Genetic Analyses of Focal Aspects of Infant Temperament.

The authors explored the genetic and environmental underpinnings of individual differences in temperament with a sample of 604 3- to 16-month-old infant twins and their parents. Mothers completed Rothbarts Infant Behavior Questionnaire (IBQ), and a subsample of 140 9-month-old twins participated in behavioral assessment of temperament in the laboratory as well. For IBQ Smiling and Laughter and Duration of Orienting, both additive genetic and shared environmental effects were needed to best represent the data. Shared environmental effects fully accounted for cotwin similarity for IBQ Soothability, and conversely, additive genetic effects fully accounted for cotwin similarity for the IBQ Distress to Limitations, Distress to Novelty, and Activity Level scales. With the subsample, the authors fit a multivariate model to mother report, father report, and lab measures of stranger distress and found that genetic influences were most important for the covariation among these measures.

Salivary alpha-amylase and cortisol in toddlers: differential relations to affective behavior.

This study applies a minimally invasive and multi-system measurement approach (using salivary analytes) to examine associations between the psychobiology of the stress response and affective behavior in toddlers. Eighty-seven 2-year-olds (48 females) participated in laboratory tasks designed to elicit emotions and behavior ranging from pleasure/approach to fear/withdrawal. Saliva samples were collected pretask and immediately posttask, and assayed for markers of sympathetic nervous system (alpha-amylase or sAA) and hypothalamic-pituitary-adrenal axis (cortisol) activity. Individual differences in sAA were positively associated with approach behavior and positive affect; whereas, cortisol was positively associated with negative affect and withdrawal behavior. The findings suggest that individual differences in sAA may covary specifically with positive affect and approach behaviors or the predominant emotional state across a series of tasks. The results are discussed with respect to advancing biosocial models of the concomitants and correlates of young childrens affective behaviors.

The development of stranger fear in infancy and toddlerhood: normative development, individual differences, antecedents, and outcomes

Despite implications that stranger fear is an important aspect of developing behavioral inhibition, a known risk factor for anxiety, normative and atypical developmental trajectories of stranger fear across infancy and toddlerhood remain understudied. We used a large, longitudinal data set (N = 1285) including multi-trait, multi-method assessments of temperament to examine the normative course of development for stranger fear and to explore the possibility that individual differences exist in trajectories of stranger fear development between 6 and 36 months of age. A latent class growth analysis suggested four different trajectories of stranger fear during this period. Stable, high levels of stranger fear over time were associated with poorer RSA suppression at 6 months of age. Rates of concordance in trajectory-based class membership for identical (monozygotic) and fraternal (dizygotic) twins, along with associations between atypical stranger fear development and greater anxiety-related maternal characteristics, suggested that individual differences in developmental trajectories of stranger fear may be heritable. Importantly, trajectories of stranger fear during infancy and toddlerhood were linked to individual differences in behavioral inhibition, with chronically high levels of stranger fear and sharp increases in stranger fear over time related to greater levels of inhibition than other developmental trajectories.

An ERP study of conflict monitoring in 4–8-year old children: Associations with temperament

Although there is great interest in identifying the neural correlates of cognitive processes that create risk for psychopathology, there is a paucity of research in young children. One event-related potential (ERP), the N2, is thought to index conflict monitoring and has been linked cognitive and affective risk factors for anxiety. Most of this research, however, has been conducted with adults, adolescents, and older children, but not with younger children. To address this gap, the current study examined 26 4-8-year-olds, who completed a cued flanker task while EEG was continuously recorded. We assessed whether the N2 was detectable in this group of young children and examined associations between the N2 and factors reflecting affective risk (e.g., reduced executive attention, temperamental effortful control, and temperamental surgency). We documented an N2 effect (greater N2 amplitude to incongruent versus congruent flankers), but only in children older than 6 years of age. Increases in the N2 effect were associated with less efficient executive attention and lower temperamental effortful control. We discuss the implications of these findings and consider how they may inform future studies on biomarkers for cognitive and affective risk factors for anxiety.

Temperamental Risk Factors for Pediatric Anxiety Disorders

Fearful temperament, most often conceptualized as behavioral inhibition, has been found to be a robust predictor for the development of pediatric anxiety disorders, with most evidence suggesting a link with social anxiety disorder. In addition to a detailed review of behavioral inhibition, recent work that supports a new construct, dysregulated fear, is also reviewed in this chapter. New evidence is presented that demonstrates that dysregulated fear is conceptually and methodologically distinct from behavioral inhibition and improves the prediction of which fearful toddlers are at risk for pediatric anxiety disorders. The following review will summarize the empirical bases for these two approaches and their role in the development of anxiety disorders, as well as evidence for biomarkers, executive processes, and parenting environment that exacerbate or ameliorate this early temperament risk. Specifically, research on fearful temperament has identified multiple trajectories and outcomes for children with the same underlying temperamental biases. That is, not all young children who display fearful temperament maintain this behavioral profile or develop anxiety symptoms. Therefore, this chapter summarizes evidence for biological, regulatory, and parental processes that account for these divergent trajectories and addresses the question of which fearful children are at highest risk for developing anxiety disorders.

Toddler fearfulness is linked to individual differences in error-related negativity during preschool.

We investigated associations between early fearfulness and error-related negativity (ERN) in preschoolers. Children were classified as low, moderate, or high in fearfulness based on observations at age 2 years. ERN was measured at age 4.5 years. ERN was visible in preschoolers who were moderate or high in fear during toddlerhood, but was characterized differently in children based on associations with fearfulness during toddlerhood. A non-localized ERN was visible across midline electrodes in high-fear children and an adult like ERN distribution was visible in moderately fearful children. In contrast, low-fear children showed no evidence of ERN at 4.5 years of age.

Error-monitoring brain activity is associated with affective behaviors in young children !,!!

Despite recent evidence that neural correlates of error monitoring such as the error-related negativity (ERN) and error positivity (Pe) are visible in children sooner than previously thought, little is known about these components early in life. Error-monitoring components can be noninvasively recorded from a very early age and have been proposed as biological markers of risk for psychopathology. Therefore, the current study represents an attempt to examine the presence of these components in a sample of very young children and explore their associations with affect and attentional control.Fifteen children between ages 4 and 8 participated in two laboratory episodes: interacting with a stranger and completing a computerized flanker task. Shy and bold behaviors were scored during the stranger interaction and parents reported on temperament-based affective behaviors. Both ERN and Pe were visible in children as young as age 4. A trend-level interaction was observed between age and gender in association with ERN amplitudes. Age and gender were unrelated to the Pe. Greater ERN and Pe were associated with better poorer orienting and greater attentional focusing, respectively. Greater Pe was also linked to less observed boldness. Implications for studies of the development of performance monitoring in children are discussed.

Allostatic and Environmental Load in Toddlers Predicts Anxiety in Preschool and Kindergarten

Psychobiological models of allostatic load have delineated the effects of multiple processes that contribute to risk for psychopathology. This approach has been fruitful, but the interactive contributions of allostatic and environmental load remain understudied in early childhood. Because this developmental period encompasses the emergence of internalizing problems and biological sensitivity to early experiences, this is an important time to examine this process. In two studies, we examined allostatic and environmental load and links to subsequent internalizing and externalizing problems. Study 1 examined relations between load indices and maladjustment, concurrently and at multiple times between age 2 and kindergarten; Study 2 added more comprehensive risk indices in a sample following a group of highly fearful toddlers from 2 to 3 years of age. Results from both studies showed that increased allostatic load related to internalizing problems as environmental risk also increased. Study 2, in addition, showed that fearfulness interacted with allostatic and environmental load indices to predict greater anxiety among the fearful children who had high levels of allostatic and environmental load. Taken together, the findings support a model of risk for internalizing characterized by the interaction of biological and environmental stressors, and demonstrate the importance of considering individual differences and environmental context in applying models of allostatic load to developmental change in early childhood.