Person:

Kagan, Jerome

Behavioral inhibition, a temperamental trait signalling a predisposition to childhood and adolescent anxiety disorders, is slightly more frequent in America among Caucasian children having blue irises. This paper examines a community sample of 101 German toddlers assessed for behavioral inhibition in a standardized laboratory procedure. Hair pigmentation was found to be significantly associated with behavioral inhibition in the sense that blond children exhibited higher fear scores. As in American samples, blue-eyed children had a higher fear score than did other children, but this difference was not statistically significant.

This paper discusses a select list of six historical conditions, some long-lasting, some of shorter duration that have influenced the research of many psychologists. The conditions are: (a) the emergence of industrialization and increased numbers of European immigrants to the United States, (b) the historical commitment to a material basis for all natural phenomena, (c) the Cold War and computers, (d) the entry of mothers into the workforce, (e) the reliance on the analysis of variance and regression, and (f) the unique position of physics among the empirical sciences.

Psychologists too often rely on only one source of evidence to affirm the validity of a construct. However, they usually do not know all the conditions that can produce the evidence they gather. Hence, the inference is often limited to the data gathered and does not generalize to other categories of information. Examples of this habit are presented along with the suggestion that all social scientists should affirm the utility of their concepts with more than one class of information.

Objective: To determine whether 4- and 14-month-old infants of mothers with panic disorder (PD) would be more likely to show differences in temperament, neurophysiology (salivary cortisol and sleep), and relationships with their mothers than controls. Method: Two cohorts were recruited: 4-month-old infants with PD mothers (n = 25) and 4-month-old controls (n = 24), and 14-month-old infants with PD mothers (n = 27) and 14-month-old controls (n = 18). Mothers completed diagnostic interviews and questionnaires concerning infant temperament, sleep, and parenting. Infant salivary cortisol samples and standard observational procedures to measure infant temperament, sleep, attachment, and parenting were also used. Results: Infants with PD mothers did not show more high reactivity, behavioral inhibition, or ambivalent/resistant attachment but did demonstrate different neurophysiology (higher salivary cortisol and more disturbed sleep) than controls. PD mothers alto displayed less sensitivity toward their infants and reported parenting behaviors concerning infant sleep and discipline that have been associated with child problems. Conclusions: While infants with PD mothers did not show early behavioral differences from controls, they did display neurophysiological divergences consistent with higher arousal/arousability. Such neurophysiological divergences (elevated salivary cortisol and disturbed sleep) might be important early indicators of risk. Helping PD mothers parent their more highly aroused/arousable infants could reduce the development of psychopathology.

A psychophysiological component to behavioral inhibition has frequently been postulated. To assess the relationship of infant cardiac basic activity, reactivity and habituation with behavioral inhibition101 full term human infants were examined. Basic heart rate and short-term heart rate variability, cardiac reactivity and habituation to an acoustic stimulus were assessed at two and six weeks postnatal age. Behavioral inhibition was measured at 14 months in a standardized laboratory procedure. Infant gender, birth weight and pre-, peri- and postnatal complications were assessed as covariates. There was a significant impact of birth weight on cardiac reactivity to the acoustic stimulus at two weeks. Habituation coefficient at two weeks was negatively associated with fear score at 14 months. These data indicate an impact of neonatal stimulus processing on fearfulness to the unfamiliar in later life.

The balance between the preservation of early cognitive functions and serious transformations on these functions shifts across time. Piaget's writings, which favored transformations, are being replaced by writings that emphasize continuities between select cognitive functions of infants and older children. The claim that young infants possess elements present in the older child's concepts of number, physical impossibility, and object permanence is vulnerable to criticism because the inferences are based primarily on the single measure of change in looking time. It is suggested that investigators use unique constructs to describe phenomena observed in young infants that appear, on the surface, to resemble the psychological competences observed during later developmental stages.

The behavioral reactions to unfamiliar events are basic phenomena in all vertebrates. Four-month-old infants who show a low threshold to become distressed and motorically aroused to unfamiliar stimuli are more likely than others to become fearful and subdued during early childhood, whereas infants who show a high arousal threshold are more likely to become bold and sociable. After presenting some developmental correlates and trajectories of these 2 temperamental biases, I consider their implications for psychopathology and the relation between propositions containing psychological and biological concepts.

One of the central questions that has occupied those disciplines concerned with human development is the nature of continuities and discontinuities from birth to maturity. The amygdala plays a central role in the processing of novelty and emotion in the brain. While there is considerable variability among individuals in the reactivity of the amygdala to novel and emotional stimuli, the origin of these individual differences is not well understood. Four month old infants called high reactive (HR) demonstrate a distinctive pattern of vigorous motor activity and crying to specific unfamiliar visual, auditory, and olfactory stimuli in the laboratory. Low-reactive infants show the complementary pattern. Here we demonstrate that the HR infant phenotype predicts greater amygdalar reactivity to novel faces almost two decades later in adults. A prediction of individual differences in brain function at maturity can be made on the basis of a single behavioural assessment made in the laboratory at four months of age. This is the earliest known human behavioural phenotype that predicts individual differences in patterns of neural activity at maturity. These temperamental differences rooted in infancy may be relevant to understanding individual differences in vulnerability and resilience to clinical psychiatric disorder. Males who were HR infants showed particularly high-levels of reactivity to novel faces in the amygdala that distinguished them as adults from all other sex/temperament subgroups, suggesting that their amygdala is particularly prone to engagement by unfamiliar faces. These findings underline the importance of taking gender into account when studying the developmental neurobiology of human temperament and anxiety disorders. The genetic study of behavioral and biologic intermediate phenotypes (or “endophenotypes”) indexing anxiety-proneness offers an important alternative to examining phenotypes based on clinically-defined disorder. Because the HR phenotype is characterized by specific patterns of reactivity to elemental visual, olfactory, and auditory stimuli, well before complex social behaviors such as shyness or fearful interaction with strangers can be observed, it may be closer to underlying neurobiological mechanisms than behavioral profiles observed later in life. This possibility, together with the fact that environmental factors have less time to impact the four-month phenotype, suggests that this temperamental profile may be a fruitful target for high-risk genetic studies.