J. Steven Reznick

The Physiology and Psychology of Behavioral Inhibition in Children.

Longitudinal study of 2 cohorts of children selected in the second or third year of life to be extremely cautious and shy (inhibited) or fearless and outgoing (uninhibited) to unfamiliar events revealed preservation of these 2 behavioral qualities through the sixth year of life. Additionally, more of the inhibited children showed signs of activation in 1 or more of the physiological circuits that usually respond to novelty and challenge, namely, the hypothalamic-pituitary-adrenal axis, the reticular activating system, and the sympathetic arm of the autonomic nervous system. It is suggested that the threshold of responsivity in limbic and hypothalamic structures to unfamiliarity and challenge is tonically lower for inhibited than for uninhibited children.

Visual scanning of faces in autism.

The visual scanpaths of five high-functioning adult autistic males and five adult male controls were recorded using an infrared corneal reflection technique as they viewed photographs of human faces. Analyses of the scanpath data revealed marked differences in the scanpaths of the two groups. The autistic participants viewed nonfeature areas of the faces significantly more often and core feature areas of the faces (i.e., eyes, nose, and mouth) significantly less often than did control participants. Across both groups of participants, scanpaths generally did not differ as a function of the instructions given to the participants (i.e., “Please look at the faces in any manner you wish.” vs. “Please identify the emotions portrayed in these faces.”). Autistic participants showed a deficit in emotion recognition, but this effect was driven primarily by deficits in the recognition of fear. Collectively, these results indicate disorganized processing of face stimuli in autistic individuals and suggest a mechanism that may subserve the social information processing deficits that characterize autism spectrum disorders.

Early development of executive function: A problem-solving framework

Executive function (EF) accounts have now been offered for several disorders with childhood onset (e.g., attention-deficit/hyperactivity disorder, autism, early-treated phenylketonuria), and EF has been linked to the development of numerous abilities (e.g., attention, rule use, theory of mind). However, efforts to explain behavior in terms of EF have been hampered by an inadequate characterization of EF itself. What is the function that is accomplished by EF? The present analysis attempts to ground the construct of EF in an account of problem solving and thereby to integrate temporally and functionally distinct aspects of EF within a coherent framework. According to this problem-solving framework, EF is a macroconstruct that spans 4 phases of problem solving (representation, planning, execution, and evaluation). When analyzed into subfunctions, macroconstructs such as EF permit the integration of findings from disparate content domains, which are often studied in isolation from the broader context of reasoning and action. A review of the literature on the early development of EF reveals converging evidence for domain-general changes in all aspects of EF.

Short-form versions of the MacArthur Communicative Development Inventories

The MacArthur Communicative Development Inventories (CDIs) are a pair of widely used parent-report instruments for assessing communicative skills in infants and toddlers. This report describes short-form versions of the CDIs and their development, summarizes newly available normative data and psychometric properties of the instruments, and discusses research and clinical applications. The infant short form (Level I, for 8- to 18-month-olds) contains an 89-word checklist for vocabulary comprehension and production. The two parallel versions of the toddler short form (Level II, Forms A and B, for 16- to 30-month-olds) each contain a 100-word vocabulary production checklist and a question about word combinations. The forms may also be useful with developmentally delayed children beyond the specified age ranges. Copies of the short forms and the normative tables appear in the appendices.

Inhibited and uninhibited types of children.

An initial group of 100 children who were not selected a priori on any behavioral features were observed in laboratory settings at 14, 20, 32, and 48 months and their behaviors coded for inhibition and lack of inhibition to the unfamiliar. The children who had been extremely inhibited or uninhibited at both 14 and 20 months differed significantly at 4 years of age in behavior and cardiac acceleration to cognitive stress. However, for the entire sample, there was no significant relation between degree of inhibited behavior at 14 or 20 months, on the one hand, and inhibition at 4 years of age, on the other, nor any relation between behavior and heart rate acceleration. These results suggest that the constructs inhibited and uninhibited to the unfamiliar refer to children who fall at the extremes of a phenotypic continuum from shyness and restraint to sociability and affective spontaneity.

The Heritability of Inhibited and Uninhibited Behavior: A Twin Study.

Young children who respond to the unfamiliar with wariness and avoidance belong to a temperamental category called behaviorally inhibited; sociable children who approach the unfamiliar are called uninhibited. This study assessed the heritable nature of these 2 categories. The longitudinal sample consisted of 178 same-sex twin pairs seen at 14 months and 162 pairs seen at 20 and 24 months. An aggregate inhibition index was constructed at each of the 3 ages by averaging standard scores for observed laboratory behaviors indicative of wariness

Temperament, Emotion, and Cognition at Fourteen Months: The MacArthur Longitudinal Twin Study

200 pairs of twins were assessed at 14 months of age in the laboratory and home. Measures were obtained of temperament, emotion, and cognition/language. Comparisons between identical and fraternal twin correlations suggest that individual differences are due in part to heritable influences. For temperament, genetic influence was significant for behavioral observations of inhibition to the unfamiliar, tester ratings of activity, and parental ratings of temperament. For emotion, significant genetic influence was found for empathy and parental ratings of negative emotion. The estimate of heritability for parental report of expression of negative emotions was relatively high, whereas that for expression of positive emotions was low, a finding consistent with previous research. For cognition and language, genetic influence was significant for behavioral indices of spatial memory, categorization, and word comprehension. Shared rearing environment appears influential for parental reports of language and for positive emotions, but not for other measures of emotion or for temperament.

Inhibited and uninhibited children: A follow-up study.

REZNICK, J. STEVEN; KAGAN, JEROME; SNIDMAN, NANCY; GERSTEN, MICHELLE; BAAK, KATHERINE; and ROSENBERG, ALLISON. Inhibited and Uninhibited Children: A Follow-up Study. CHILD DEVELOPMENT, 1986, 57, 660-680. A group of 46 children classified at 21 months as either behaviorally inhibited or uninhibited, and 18 children who were classified as falling at neither extreme, were observed at 5 /2years of age in contexts designed to evaluate behavior in social situations and heart rate, heart rate variability, and pupillary dilation to cognitive tasks. Additionally, 43 of the 46 inhibited or uninhibited children had been evaluated in similar contexts when they were 4 years of age. At age 51/, the formerly inhibited children, compared with the uninhibited ones, were more inhibited with peers in both laboratory and school, as well as with an adult examiner in a testing situation, and more cautious in a situation of mild risk. As at the earlier ages, more inhibited children had a relatively high and stable heart rate. The inhibited children also had tonically larger pupillary dilations to cognitive stress, were either impulsive or reflective on a test with response uncertainty, and their mothers described them as shy with unfamiliar peers. It was suggested that one or more of the stress circuits that link the hypothalamus to the pituitary, reticular activating system, and sympathetic chain are at a higher level of excitability among inhibited than among uninhibited children.

Further evidence of an association between behavioral inhibition and anxiety disorders: Results from a family study of children from a non-clinical sample

Abstract Behavioral inhibition to the unfamiliar, identifiable in early childhood and reflecting the tendency to exhibit withdrawal and excessive autonomic arousal to challenge or novelty, has been found to be prevalent in young offspring of parents with panic disorder and agoraphobia and associated with risk for anxiety disorders in these children. Using family study methodology, we now examine psychopathology in first degree relatives of children from a non-clinical longitudinal cohort identified at 21 months of age as inhibited ( N =22) or uninhibited ( N =19) and followed through the age of seven years for a study of preservation of temperamental characteristics in normal children. These assessments were compared with evaluations of the first degree relatives of 20 normal comparison children. Psychiatric assessments of parents ( N =110) and siblings ( N =72) were based on structured interviews conducted blindly to the temperamental classification of the index child. Parents of inhibited children, compared with parents of uninhibited and normal controls, had significantly higher risks for multiple (≥2) anxiety disorders, continuing anxiety disorders (both a childhood and adulthood anxiety disorder in the same parent), social phobia, and childhood avoidant and overanxious disorders. These findings provide additional support for the hypothesis linking behavioral inhibition with risk for anxiety disorder.

The effects of socioeconomic status, race, and parenting on language development in early childhood.

The authors examined the associations between socioeconomic status (SES), race, maternal sensitivity, and maternal negative-intrusive behaviors and language development in a sample selected to reduce the typical confound between race and SES (n = 146). Mother-child interactions were observed at 12 and 24 months (coded by randomly assigned African American and European American coders); language abilities were assessed at 18, 24, 30, and 36 months. For receptive language, race was associated with ability level, and maternal sensitivity and negative-intrusive parenting were related to rate of growth. For expressive communication, race, SES, and maternal sensitivity were associated with rate of growth; race moderated the association between negative-intrusive parenting and rate of growth such that the relation was weaker for African American than for European American children. The results highlight the importance of sensitive parenting and suggest that the association between negative-intrusive parenting and language development may depend upon family context. Future work is needed concerning the race differences found, including examining associations with other demographic factors and variations in language input experienced by children, using culturally and racially validated indices of language development.