Infant reactivity: Physiological correlates of newborn and 5-month temperament.

The relation between measures of heart period and vagal tone and infant reactivity was investigated in a longitudinal study of infants from birth to 5 months of age. At 2 days of age, electrocardiogram (EKG) was recorded and a pacifier-withdrawal task was administered. At 5 months of age, EKG was recorded, after which infants and mothers participated in a laboratory session designed to elicit positive and negative reactivity. Maternal ratings of 5-month infant temperament were also obtained. There was a significant concurrent relation between 5-month vagal tone and negative reactivity elicited in the laboratory and maternal ratings of activity level and smiling behavior. Newborn vagal tone predicted maternal ratings of frustration and fear. Moderate stability was found for infant reactivity. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Psychophysiological correlates of emotional reactivity during the first year of life.

Emotional reactivity is an important dimension thought to underlie individual differences in infant temperament. In a series of studies, we have examined the relation between behaviors reflecting this dimension and measures of heart rate variability. In the current study, longitudinal behavioral data on two groups of infants selected for their pattern of heart period variability are presented: those with high vagal tone (high heart rate variability) and those with low vagal tone (low heart rate variability) at 14 months of age. The data suggest that infants with high vagal tone were more reactive to both positive and negative events at 5 months and more sociable and approachful at 14 months. Infant reactivity to mildly stressful events seems to be a stable dimension during the first year, and there is a strong association between differences in reactivity and the degree to which the autonomic nervous system is influenced by vagal tone. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infant temperament and cardiac vagal tone: assessments at twelve weeks of age

Sixty 12-week-old infants participated in a laboratory study to explore the relations between temperament and cardiac vagal tone. Temperament was evaluated via laboratory observations and maternal ratings. Cardiac vagal tone, measured as the amplitude of respiratory sinus arrhythmia, was quantified from beat-to-beat heart period data collected during a resting baseline period and during the laboratory assessment of temperament. Specific hypotheses were investigated relating temperament to both basal cardiac vagal tone and changes in cardiac vagal tone during social/attention challenges. Infants with higher baseline cardiac vagal tone were rated in the laboratory as showing fewer negative behaviors and were less disrupted by the experimental procedure. Infants who decreased cardiac vagal tone during the laboratory assessment were rated on maternal report temperament scales as having longer attention spans, and being more easily soothed.     

Longitudinal observation of infant temperament.

Convergent validity, temporal stability, and age-related patterning of measures of infant temperament were examined in a longitudinal study of 46 infants at 3, 6, and 9 mo of age. At each age, mothers completed the Infant Behavior Questionnaire (IBQ), and the behavior of infants and their mothers was observed at home and during bath, feeding, and play. Temperamental dimensions of activity level, smiling and laughter, distress to limitations, fear, and vocal activity were investigated. Findings show that the IBQ and home observations, corrected for attenuation, showed convergent validity for all 5 temperament scales at 3 mo and for 4 of 5 scales at both 6 and 9 mo of age. Composite measures of positive and negative reactivity and overall reactivity showed significant convergence at all ages, with the exception of the positive composite at 3 mo of age. Relative stability of positive reactivity was found across both 3- and 6-mo intervals, whereas negative reactivity and overall reactivity showed stability only across 3-mo periods. Whereas no sex differences or sex?×?age interactions were found using the reactivity measures, when the measures of smiling and laughter, activity level, and vocal activity (which formed the positive reactivity composite when combined) were used independently, they showed an increase with age. Results support the use of the IBQ. (64 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fetal antecedents of infant temperament

This study established the emergence of stable individual differences in neurobehavioral functioning prior to birth and examined their relation to subsequent infant temperament. Fetal heart rate and movement were recorded longitudinally for 31 fetuses at 6 gestational ages beginning at 20 weeks' gestation. Maternally reported temperament data were collected at 3 and 6 months. Moderate stability in all measures except reactivity was apparent at some time before birth. By 36 weeks, fetal neurobehavior accounted for between 22% and 60% of the variance in prediction of temperament scores. In general, more active fetuses were more difficult, unpredictable, unadaptable, and active infants. Higher fetal heart rate was associated with lower emotional tone, activity level, and predictability. We conclude that features of fetal neurobehavior provide the basis for individual differences in reactivity and regulation in infancy.     

Individual differences in emotion regulation and behavior problems in preschool children.

Emotion regulation (ER) was assessed during a negative mood induction in 79 preschoolers who varied in degree of behavior problems. Facial expressivity during the induction was used to identify 3 ER groups: inexpressive, modulated expressive, and highly expressive. Group differences in ER were significantly related to heart rate and skin conductance. Inexpressive preschoolers had the highest heart rate, lowest vagal tone, and smallest autonomic nervous system (ANS) change during the induction. Highly expressive preschoolers had the slowest heart rate, highest vagal tone, and largest ANS change. The inexpressive and highly expressive groups had more externalizing symptoms than the modulated group at preschool age and at follow-up at the end of 1st grade. Inexpressive preschoolers appeared to have more depressed and anxious symptoms at follow-up. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the association of interparental conflict with developing behavioral inhibition and behavior problems in early childhood.

Associations between interparental conflict and the development of temperament characteristics have seldom been addressed; moreover, studies on the impact of interparental conflict on developing behavior problems in infancy and early childhood are relatively rare. The authors therefore aimed to contribute to the study of these issues. A sample of 64 families was investigated longitudinally. At the infant age of 4 months, negative emotionality was measured with a laboratory routine. When infants were 4, 8, and 12 months old, maternal sensitivity was assessed during home observations, and interparental conflict was measured by means of questionnaires. When infants were 30 months old, behavioral inhibition was measured in 2 laboratory fear episodes, and behavior problems were assessed with a structured clinical interview of the primary caregiver. Interparental conflict and infant negative emotionality were significantly and independently associated with subsequent behavioral inhibition. The association of interparental conflict with behavior problems was moderated by infant negative emotionality. Infants high in negative emotionality developed more serious behavior problems when exposed to high interparental conflict, whereas the association was not significant in infants low in negative emotionality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental and cross-situational stability in infant pigtailed macaque temperament.

We assessed developmental stability and context generalizability of temperament in pigtailed macaques (Macaca nemestrina) from the University of Washington Infant Primate Research Lab. A principal components analysis condensed 6 behavioral measures into 2 components, interpreted as reactivity and boldness. Changes in these measures over the 1st 10 months of development showed a trend toward calmer and bolder behavior with age, with significant individual variation in the pattern of change. Boldness showed a quadratic pattern of change, whereas reactivity decreased linearly. We also studied the relationship between temperament and response to a novelty probe. The magnitude of the response to the novelty probe decreased slightly over time, and boldness and reactivity in a familiar setting did not predict these changes in response to novelty. In a 2nd principal components analysis, reactivity to novelty represented a distinct aspect of temperament. Our results demonstrate developmental changes and context dependency in macaque behavior. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Infants' Vagal Regulation in the Still-Face Paradigm Is Related to Dyadic Coordination of Mother-Infant Interaction.

The authors investigated relations between mother-infant dyadic coordination and infants' physiological responses. Mothers (N=73) and 3-month-old male and female infants were observed in the still-face paradigm, and mothers' and infants' affective states were coded at 1-s intervals. Synchrony and levels of matching between mother-infant affective states were computed, and infants' heart rate and vagal tone were measured. Infants showed increased negative affect and heart rate and decreased vagal tone during mothers' still-face, indicating physiological regulation of distress. Infants who did not suppress vagal tone during the still-face (nonsuppressors) showed less positive affect, higher reactivity and vagal suppression in normal play and reunion episodes, and lower synchrony in normal play with mothers. The results indicate that infants' physiological regulation in social interaction differs in relation to dyadic coordination of affective behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frontal brain asymmetry predicts infants' response to maternal separation.

Examined whether certain features of infant temperament might be related to individual differences in the asymmetry of resting frontal activation. EEG was recorded from the left and right frontal and parietal scalp regions of 13 normal 10-month-old infants. Infant behavior was then observed during a brief period of maternal separation. Those infants who cried in response to maternal separation showed greater right frontal activation during the preceding baseline period compared with infants who did not cry. Frontal activation asymmetry may be a state-independent marker for individual differences in threshold of reactivity to stressful events and vulnerability to particular emotions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infants of postpartum depressed mothers: Temperament and cognitive status.

This study examined the association of postpartum depression with specific infant characteristics. Twenty-five diagnosed depressed and 25 nondepressed mothers and their 2-month-old infants participated in the study. The mothers completed measures of infant temperament and difficulty associated with infant care, and the infants were assessed using the Bayley Scales of Infant Development. Group comparisons indicated that, compared with the infants of the nondepressed mothers, the infants of the depressed women were less competent cognitively and expressed more negative emotions during the testing. The depressed mothers perceived their infants as more difficult to care for and more bothersome than did the nondepressed mothers, but did not attribute these difficulties to the temperament of their infants. These findings suggest that postpartum depression is associated with an identifiable pattern of infant behavior that may exacerbate depressed women's mood. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Association between cardiac autonomic function and coping style in healthy subjects

The link between personality and cardiac function is insufficiently characterized. We postulated that in a healthy population, cardiac autonomic function is linked to coping style. In 276 healthy volunteers, between the ages of 18 and 71, the Utrecht Coping List was used to evaluate different coping strategies. Trait anxiety was scored by the Spielberger State Trait Anxiety Inventory. A 24-hour Holter recording was used to calculate heart rate variability (HRV). For HRV parameters and coping mechanisms this study demonstrated gender-specific differences and correlations with age. In men (n = 141) higher active coping was associated with less global autonomic activity or SDANN (rs = -0.27, P < 0.001). This relationship was most prevalent in young (18-30 years) men (rs = -0.45, P < 0.005). Higher expression of negative emotions or anger was related to both higher vagal (rs = 0.23 for rMSSD, P < 0.01) tone and higher LF power (rs = 0.23, P < 0.01). In young men expression of negative emotions or anger was associated with LF power (rs = 0.37, P < 0.01) and in middle-aged (31-50 years) men with vagal tone (rs = 0.43 for rMSSD, P < 0.005) and heart rate (rs = -0.41, P < 0.005). Higher comforting ideas was related to higher LF power (rs = 0.23 for LF power, P < 0.005), and this especially in middle-aged men (rs = 0.37, P < 0.01). In women (n = 135), no significant correlations between coping style and HRV indices were found. We conclude that in normal individuals, at least in men, our findings suggest a relationship between coping style and cardiac autonomic function.     

Attachment, temperament, and adrenocortical activity in infancy: A study of psychoendocrine regulation.

Examined the relations among adrenocortical stress reactivity, infant emotional or proneness-to-distress temperament, and quality of attachment in 66 infants tested at 9 and at 13 months. Performed the Louisville Temperament Assessment at 9 months and conducted the Strange Situation at 13 months. Adrenocortical activity was not associated with attachment classifications. Emotional temperament at 9 months was strongly correlated with emotional temperament at 13 months. There was also evidence that at both ages infants who were more prone to distress experienced greater increases in adrenocortical activity during the laboratory tests. Significantly, however, although both the Louisville Temperament Assessment and the Strange Situation involve maternal separation (a potent stimulant of the adrenocortical system in nonhuman primate infants), we noted only small elevations in cortisol, and these elevations were significant only at 9 months. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mother-infant affect synchrony as an antecedent of the emergence of self-control

This study examined relations between mother-infant affect synchrony and the emergence of children's self-control. Mother-infant face-to-face play and infant difficult temperament were examined at 3 and 9 months. Maternal and infant affective states at play were coded in 0.25-s frames, and synchrony was computed with cross-correlation functions. Self-control, verbal IQ, and maternal warm discipline were assessed at 2 years. Maternal synchrony with infant affect at 3 months (infant-leads-mother-follows relation) and mutual synchrony at 9 months (cross-dependence between maternal and infant affect) were each related to self-control at 2 years when temperament, IQ, and maternal style were partialed. Infant temperament moderated the relations of synchrony and self-control, and closer associations were found between mutual synchrony and self-control for difficult infants. Shorter lags to maternal synchrony at 3 months were independently related to self-control. The mutual regulation of affect in infancy, as moderated by temperament, is proposed as an important contributor to the emergence of self-regulation.     

Mothers' ratings of the temperament characteristics of Down Syndrome infants.

Using Carey's Infant Temperament Questionnaire, mothers' ratings of temperament characteristics of 74 Down's syndrome (DS) infants (aged 4–24 mo) were obtained and compared with those in Carey's standardization sample of normal infants. The stability of the ratings over a 6-mo interval was also examined. Mothers' assessments of their DS infants' behavior did not support the stereotype that DS infants are easier, more placid, and less intense than normal infants. On 6 of the 9 temperament dimensions rated (Activity, Intensity, Mood, Adaptability, Distractibility, and Rhythmicity), no significant differences between the ratings of DS and normal infants were found. Moreover, when the DS infants were considered as members of the Carey sample, a greater percentage of DS than of normal infants were found in more difficult temperament categories. Ss scored lower than the standardization sample on the dimensions of Persistence, Approach, and Threshold. Findings are discussed in terms of qualitative differences in the development of affect in DS infants and the impact that such differences may have on caregiver–infant interactive processes and mothers' assessments of infant behavior. Finally, comparison of individual- and group-level analyses of the stability of temperament ratings revealed discrepancies that suggest the importance of distinguishing the meaning of these types of stability analyses. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Natural forms of shed tumor gangliosides

Data on activity states were collected from 29 group-housed capuchin monkey (Cebus apella) infants for 3 h each week from birth to 11 weeks of age. The amounts of time spent in sleeping/drowsy, alert-quiet, and alert-active states were measured in these subjects. Videotaped observations of these infants were recorded 3 times/week in the home cage over the first year of life and were scored for a number of social and exploratory behaviors. The extent to which early infant activity state scores predicted later behavior in the home cage was examined. Infant state measures correlated significantly with home cage behavior during months 2-6 in that infants that had been more active in early infancy spent more time alone, with other animals, and in exploration and play and less time with mothers than did quieter infants. Early state measures were less successful in predicting home cage scores beyond 8 months of age, whereas differences in behavior attributable to housing variables became more salient in the latter part of the first year. There was also a negative correlation between mother and infant activity in months 2 and 3, in that more sedentary mothers tended to have more active infants.     

Mother–infant affect synchrony as an antecedent of the emergence of self-control.

This study examined relations between mother–infant affect synchrony and the emergence of children's self-control. Mother–infant face-to-face play and infant difficult temperament were examined at 3 and 9 months. Maternal and infant affective states at play were coded in 0.25-sec frames, and synchrony was computed with cross-correlation functions. Self-control, verbal IQ, and maternal warm discipline were assessed at 2 years. Maternal synchrony with infant affect at 3 months (infant-leads-mother-follows relation) and mutual synchrony at 9 months (cross-dependence between maternal and infant affect) were each related to self-control at 2 years when temperament, IQ, and maternal style were partialed. Infant temperament moderated the relations of synchrony and self-control, and closer associations were found between mutual synchrony and self-control for difficult infants. Shorter lags to maternal synchrony at 3 months were independently related to self-control. The mutual regulation of affect in infancy, as moderated by temperament, is proposed as an important contributor to the emergence of self-regulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parents' Personality and Infants' Temperament as Contributors to Their Emerging Relationship.

The authors examined the contributions of infant's temperament and parent's personality to their relationship. In Study 1, 102 infants, mothers, and fathers were studied when infants were 7 months; in Study 2, 112 infants and mothers were followed from 9 to 45 months. Infants' temperament (joy, fear, anger, and attention) was observed in standard temperament paradigms. Parents' personality measures encompassed the Big Five traits and Empathy in Study 1 and Mistrust, Manipulativeness, Aggression, Dependency, Entitlement, and Workaholism in Study 2. Parent-child relationship (shared positive affect and parental responsiveness in Studies 1 and 2 and parental tracking of the infant in Study 1) was observed in naturalistic contexts. In Study 1, mothers' Neuroticism, Empathy, and Conscientiousness and fathers' Agreeableness, Openness, and Extraversion related to the relationship with the infants. All measures of infant temperament also related to the emerging relationship. In Study 2, maternal Mistrust, Manipulativeness, Dependency, and Workaholism predicted the relationship with the child. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Major depression and cardiac autonomic control

We investigated autonomic control of heart rate in patients with major depression, melancholic type. Twenty-three depressed inpatients who were being treated with tricyclic antidepressants and 23 depressed patients who were taking no medications were compared with age- and sex-matched control groups on resting cardiac vagal tone and heart rate. In unmedicated depressed patients, cardiac vagal tone was comparable to that of control subjects, but heart rate was significantly higher. This increase in heart rate may have been due to sympathetic activation caused by anxiety, since the depressed patients were significantly more anxious than the control subjects. Medicated patients exhibited diminished cardiac vagal tone and higher heart rate than unmedicated patients and controls. This was probably due to the anticholinergic effects of the antidepressants. Our findings suggest that cardiac vagal tone is not lower than normal in patients with depression, melancholic type.     

Children's emotion regulation: Self-report and physiological response to peer provocation.

The authors examined the notion that children's emotion regulation (ER) is a uniform skill by (a) investigating the concordance between self-report of ER and physiological measures and by (b) examining ER in a specific context (e.g., peer provocation) and context-free manner (e.g., during a semistructured interview of ER abilities). Seventy-two children in middle childhood (average age = 9 years) participated. Time-locked measures of heart rate reactivity and recovery were obtained in response to provoking comments, and vagal regulation was measured throughout the provocation session. Children who reported greater dysregulation showed increased heart rate reactivity to provocative comments (i.e., steeper heart rate slope) but no difference in heart rate recovery. The context-free but not the context-specific self-report measure was associated with a failure to suppress vagal tone. Implications for ER measurement and children's peer relations are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)