Common Themes and Cultural Variations in Japanese and American Mothers' Speech to Infants

This study explored both universal features and cultural variation in maternal speech. Japanese and American mothers' speech to infants at 6, 12, and 19 months was compared in a cross-sectional study of 60 dyads observed playing with toys at home. Mothers' speech in both cultures shared common characteristics, such as linguistic simplification and frequent repetition, and mothers made similar adjustments in their speech to infants of different ages. American mothers labeled objects more frequently and consistently than did Japanese mothers, while Japanese mothers used objects to engage infants in social routines more often than did American mothers. American infants had larger noun vocabularies than did Japanese infants, according to maternal report. The greater emphasis on object nouns in American mothers' speech is only partially attributable to structural differences between Japanese and English. Cultural differences in interactional style and beliefs about child rearing strongly influence the structure and content of speech to infants.     

Event-related Potentials in Year-Old Infants: Relations with Emotionality and Cortisol

Event-related po-potentials (ERPs) were recorded from year-old infants presented with sets of familiar faces presented frequently and infrequently, and a set of novel faces presented infrequently. The normative response of infants in this sample was a late positive slow wave to the Infrequent Familiar faces, and a return to baseline to the Frequent Familiar and Infrequent Novel faces (although there was a tendency for some infants to show a positive slow wave to the latter events). A factor score based on data from frontal and central leads that reflected this normative pattern was significantly associated with infant emotional behavior and cortisol. Infants scoring higher on the normative ERP factor were more distressed during separation, were reported by their parents to smile and laugh more, and had lower cortisol concentrations during ERP testing. These data were interpreted as reflecting the coordination of adaptive responding among different physiological and behavioral systems.     

Cortisol Release in Infants in Response to Inoculation

Using a cross-sectional design, salivary cortisol was obtained from infants aged 2, 4, and 6 months, prior to and 15 min following an inoculation. Cortisol rose significantly following inoculation. Behavioral responses to inoculation were consistent with the observed patterns of cortisol release. Cortisol base level was significantly and negatively related to the cortisol change score. At 6 months the basal levels also were influenced by an adult-like circadian rhythm; infants tested shortly after awakening had higher basal levels than those tested later in the day. These data provide strong evidence that studies of stress and cortisol release in infants must be sensitive to basal level, circadian rhythm, and behavioral effects, and that appropriate statistical procedures should be employed.     

Modalities of Infant–Mother Interaction in Japanese,Japanese American Immigrant,and European American Dyads

Cultural variation in relations and moment‐to‐moment contingencies of infant–mother person‐oriented and object‐oriented interactions were compared in 118 Japanese, Japanese American immigrant, and European American dyads with 5.5‐month‐olds. Infant and mother person‐oriented behaviors were related in all cultural groups, but infant and mother object‐oriented behaviors were related only among European Americans. Infant and mother behaviors within each modality were mutually contingent in all groups. Culture moderated lead–lag relations: Japanese infants were more likely than their mothers to respond in object‐oriented interactions; European American mothers were more likely than their infants to respond in person‐oriented interactions. Japanese American dyads behaved like European American dyads. Interactions, infant effects, and parent socialization findings are set in cultural and accultural models of infant–mother transactions.     

Developmental Change in Infant Cortisol and Behavioral Response to Inoculation

Child Development, 1994, 65 , 1491–1502. Infant cortisol and behavioral responses to receiving 1 versus 2 inoculations on 1 pediatric office visit were observed at 2 and 6 months of age. Cortisol level (pre- plus postinoculation level) decreased with age, whereas cortisol response (post- minus preinoculation level) did not vary with age when the data were aggregated over infants showing a pre- to postinoculation cortisol increase and those showing a decrease. Nonetheless, for those infants who showed a cortisol increase, cortisol level and response decreased with age. Infants quieted faster at the older age. There was a moderate relation between quieting behavior and cortisol response, at least for infants who showed a pre- to postinoculation cortisol increase. These findings indicate a developmental trend for a decline over age in adrenocortical reactivity to inoculation for infants showing a cortisol release following the perturbation. Results were comparable whether infants received 1 or 2 inoculations.     

Examining stress reactivity in neonates: relations between cortisol and behavior

The association between cortisol and behavioral reactivity to a medical heel stick and a neurobehavioral exam was examined in 100 healthy African American neonates, who have been underrepresented in this area of research. Using continuous measures, behavioral distress was associated with cortisol reactivity to both stressors. High levels of behavioral distress, however, were associated with cortisol reactivity only in response to the neurobehavioral exam. In contrast, low levels of behavioral distress were associated with cortisol reactivity only in response to the heel stick. The results highlight potentially important parameters for exploring the relation between biological and behavioral reactivity to stress such as the operationalization of behavioral distress and the context in which a stress response is elicited.     

Infants entering foster care compared to other infants using birth status indicators

Objective: Infants comprise nearly one fourth of all entries to foster care. Linkage of administrative birth and placement data can provide information about these infants that may otherwise be unavailable or difficult to obtain.Method: Statewide birth records and foster care placement histories were linked via probability matching. Logit regression was used to compare 26,460 maltreated infants who entered foster care between 1989 and 1994 with a random sample of 68,401 other infants born during that time frame.Results: Infants in care were more than twice as likely to have single parents and be born with low birthweight, and twice as likely to have been born with a birth abnormality as other infants, controlling for other factors. The largest difference was in the eightfold increased likelihood for mothers of infants in care to have had no prenatal care. Infants in care were nearly three times as likely to be born into larger families (third or greater live births to the mother). Mothers of infants in care were more than twice as likely to be African American compared to White than mothers of other infants, while Hispanic and Other ethnic groups were underrepresented in the group of infants in care. Foreign born mothers, especially Hispanic women, were much less likely to have infants in care than they were to have children in the other group.Conclusions: Administrative datasets, while often limited in the number of variables they include and scope of their information, can be a valuable tool when used to understand demographics and frame questions for future research. Infants who enter foster care differ in substantial ways from other children. These findings have important implications for future research aimed toward targeting of child welfare services and supports.     

Biobehavioral Organization in Securely and Insecurely Attached Infants

Attachment research has shown the emergence of individual differences in the security of infant-mother attachment during the first year of life as well as their importance for later social-emotional development. A biobehavioral perspective may help settle disagreements about the validity and interpretation of 12-month-old infants' different behavioral patterns of attachment assessed by Ainsworth's Strange Situation. It was shown that, despite less overt distress in insecure-avoidant infants after short separations from the mother, overall cardiac measures indicate arousal patterns similar to the secure infants during separation. However, differences in cardiac response emerged with regard to object versus person orientation during reunion. Additionally, findings of increased cortisol in both insecure-avoidant and disorganized infants support the theoretical interpretation that these infants, in contrast to secure infants, lack an appropriate coping strategy.     

Developmental Change in Infants' Responses to Stress

Infant stress responses to a well-baby physical examination and inoculation were observed longitudinally at 2, 4, and 6 months of age. In general, there were cortisol increases over base to the procedures. Cortisol level and cortisol response decreased with age. These data indicate a developmental shift in adrenocortical functioning between 2 and 6 months of age. Further evidence for this shift was seen in the stability of individual responses between 4 and 6 months of age. Individual differences in both cortisol and behavioral responses showed the most stability between these 2 ages. Moreover, diurnal variation in baseline cortisol level was present only at 6 months of age. While a sizable minority of infants showed stress-related cortisol decreases to the procedures at a given age, there was no evidence for cross-age consistency in individual infants showing these cortisol decreases.     

Dampening of Adrenocortical Responses during Infancy: Normative Changes and Individual Differences

Changes in cortisol and behavioral responses were examined longitudinally in 83 infants (39 girls, 44 boys) tested at their well-baby exams with inoculations at 2, 4, 6, and 15 months (72 infants completed all testing). Another sample of 2-, 4-, and 6-month-olds ( n = 18 per age) received mock exams without inoculations to determine early developmental changes to the exam procedures. Behavioral distress was coded every 30 sec during the exam, a 5-min inoculation period, and a 20-min recovery period. Salivary cortisol was obtained upon arrival at the clinic and 25 min after the beginning of the inoculation period. To the exam-inoculation procedures, cortisol responses were high at 2 months, decreased significantly between 2 and 4 months, remained comparable between 4 and 6 months, and then declined again between 6 and 15 months. Between 6 and 15 months there was also a decrease in pretest cortisol. By 15 months, significant increases in cortisol from pre- to posttest were no longer observed for most infants. To the exam-only procedures, cortisol responses decreased between 2 and 4 months, and by 4 months most infants failed to show pre- to posttest increases in cortisol. Behavioral distress decreased between 2 and 6 months, but increased again at 15 months. While crying and cortisol were modestly correlated during the 2- to 6-month exam-inoculation procedures, at 15 months no significant correlations were obtained. Behavioral and hormonal reactions thus followed different ontogenetic paths and may provide different information about infant functioning. There was some evidence that the emergence of the circadian rhythm in cortisol might be related to the early decrease in cortisol response.     

Mastery Motivation in Deaf and Hearing Infants

The motivational characteristics of a small sample of normally developing deaf and hearing 12-month-old infants were assessed using procedures derived from Yarrow's work. The data supported the following conclusions: 1. Both deaf and hearing infants exhibit similar amounts of motivated behavior toward objects which suggests that auditory contact with their surroundings is not a determining factor in infants' attempts to master objects. 2. The deaf infants spent a longer period of time engaged in social behaviors than did the hearing infants and without any apparent sacrifice to the deployment of their task- and goal-directed activities. This finding implies that the deaf infants were more skillful at integrating the competing demands of social- and object-oriented endeavors than were their hearing peers. 3. The deaf infant engaged with the social environment and displayed a positive emotional response to the situation sooner than the hearing infants. Positive affect also was more likely to be followed by a social behavior for the deaf infants which indicates that the integration of social- and object-oriented activities serves either a different or more potent function in the early development of deaf infants. We believe that these data offer some preliminary, empirically based support for a developmental difference model when intervention strategies for deaf infants are contemplated. The policy implications for such a move may include a reduction in cognitively oriented activities and an increase in activities designed to capitalize on deaf infants' social and visual compensatory skills.     

Morning-to-afternoon increases in cortisol concentrations for infants and toddlers at child care: age differences and behavioral correlates

This study examined salivary cortisol, a stress-sensitive hypothalamic-pituitary-adrenocortical (HPA) axis hormone in 20 infants (12 females; M age = 10.8 months) and 35 toddlers (20 females; M age = 29.7 months) in full-day, center-based child care. Samples were taken at approximately 10:00 a.m. and 4:00 p.m. at child care and at home. At child care, 35% of infants and 71% of toddlers showed a rise in cortisol across the day; at home, 71% of infants and 64% of toddlers showed decreases. Toddlers who played more with peers exhibited lower cortisol. Controlling age, teacher-reported social fearfulness predicted higher afternoon cortisol and larger cortisol increases across the day at child care. This phenomenon may indicate context-specific activation of the HPA axis early in life.     

Behavioral and physiological responsivity, sleep, and patterns of daily cortisol production in infants with and without colic

To describe the behavioral and physiological responses associated with colic, the responses of 20 two-month-old infants with and 20 without colic were studied during a physical examination. Parents kept a diary of infant behaviors (including crying and fussing) for 3 days following the visit. Using Wessel, Cobb, Jackson, Harris, & Detwiler criteria, colic was defined as fussing/crying for 3 hr or more on each of the 3 days. Behavioral data coded by "blind" observers showed that during the physical exam, colic infants cried twice as much, cried more intensely, and were more inconsolable than were control infants. Despite these behavioral differences, heart rate, vagal tone, and cortisol measures indicated no appreciable difference in physiological responsivity for the two groups. At home, parents collected saliva cortisol samples at wakeup, midmorning, midafternoon, and evening for 2 days. In a finding similar to that shown by the laboratory data, the colic and control infants did not have different levels of daily average cortisol. These laboratory and home data provide no evidence of greater responsivity in the physiological substrate of difficult temperament for colic infants and are consistent with evidence of similarity in temperament once colic is resolved. At home, compared with control infants, colic infants did display a blunted rhythm in cortisol production. By diary, they also slept about 2 hr less per day than did control infants. Nighttime sleep was still significantly different when fussing/crying was statistically controlled. These data suggest that colic might be associated with a disruption or delay in the establishment of the circadian rhythm in activity of the hypothalamic-pituitary-adrenocortical axis and associated sleep-wake activity.     

Attachment in Monkey Infants Raised in Variable- and Low-Demand Environments

12 bonnet macaque (Macaca radiata) mother-infant dyads were studied. For 14 weeks, beginning when the infants were a mean age of 11.2 weeks, the dyads were housed and observed under different foraging-demand conditions for the mothers: 6 dyads in a low-foraging-demand (LFD) condition and 6 dyads in a variable-foraging-demand (VFD) conditions. For VFD mothers, demand varied between low and high in 2-week blocks. Differences between the LFD and VFD groups were minimal during this period; there was, however, more maternal grooming and shorter separation bouts in the VFD group than in the LFD group. The dyads were then challenged by brief introductions to a novel environment. The challenge revealed that frequency of breaking dyadic contact and levels of play were significantly lower for the VFD infants than for the LFD infants, perhaps as a consequence of less secure attachment.     

Approval and Disapproval: Infant Responsiveness to Vocal Affect in Familiar and Unfamiliar Languages

In a series of 5 auditory preference experiments, 120 5-month-old infants were presented with Approval and Prohibition vocalizations in infant-directed (ID) and adult-directed (AD) English, and in ID speech in nonsense English and 3 unfamiliar languages, German, Italian, and Japanese. Dependent measures were looking-time to the side of stimulus presentation, and positive and negative facial affect. No consistent differences in looking-time were found. However, infants showed small but significant differences in facial affect in response to ID vocalizations in every language except Japanese. Infants smiled more to Approvals, and when they showed negative affect, it was more likely to occur in response to Prohibitions. Infants did not show differential affect in response to Approvals and Prohibitions in AD speech. The results indicate that young infants can discriminate affective vocal expressions in ID speech in several languages and that ID speech is more effective than AD speech in eliciting infant affect.     

Reactivity and regulation in cortisol and behavioral responses to stress

This study examined relations between reactivity (i.e., peak response) and regulation (i.e., response dampening) in 6-month-old infants' cortisol and behavioral responses to inoculation (N = 62). Data showed that reactivity and regulation were unrelated for both cortisol and behavior. The independence of reactivity and regulation suggests that measures of both are needed to characterize infant cortisol or behavioral response to stress more completely. For both reactivity and regulation, cortisol and behavior were unrelated, suggesting that measures of both are needed to assess infant stress more adequately. There was considerable variation in the timing of the peak cortisol response, suggesting that obtaining only a single poststressor cortisol sample does not provide a sensitive measure of cortisol reactivity.     

Mastery Motivation in Deaf and Hearing Infants

The motivational characteristics of a small sample of normally developing deaf and hearing 12-month-old infants were assessed using procedures derived from Yarrow's work. The data supported the following conclusions: 1. Both deaf and hearing infants exhibit similar amounts of motivated behavior toward objects which suggests that auditory contact with their surroundings is not a determining factor in infants' attempts to master objects. 2. The deaf infants spent a longer period of time engaged in social behaviors than did the hearing infants and without any apparent sacrifice to the deployment of their task- and goal-directed activities. This finding implies that the deaf infants were more skillful at integrating the competing demands of social- and object-oriented endeavors than were their hearing peers. 3. The deaf infant engaged with the social environment and displayed a positive emotional response to the situation sooner than the hearing infants. Positive affect also was more likely to be followed by a social behavior for the deaf infants which indicates that the integration of social- and object-oriented activities serves either a different or more potent function in the early development of deaf infants. We believe that these data offer some preliminary, empirically based support for a developmental difference model when intervention strategies for deaf infants are contemplated. The policy implications for such a move may include a reduction in cognitively oriented activities and an increase in activities designed to capitalize on deaf infants' social and visual compensatory skills.     

Environmental control, social context, and individual differences in behavioral and cortisol responses to novelty in infant rhesus monkeys

The effects of appetitive controllability on behavioral and cortisol reactivity to novelty in 12 infant rhesus monkeys were studied. Surrogate-peer-reared infants had homecage access to food treats contingently via lever pressing ("master") or noncontingently ("yoked") for 12 weeks from postnatal month 2. Masters lever-pressed more, but did not differ in baseline cortisol. At month 5, infants were exposed to a novel environment in social groups and individually. Masters were significantly more active and exhibited significantly lower cortisol reactivity to the novel environment, but only in the individual context. Also, individual differences in operant behavior were positively correlated with behavioral activity and negatively correlated with cortisol reactivity to the novel environment. The results reveal context-specific benefits of contingent stimulation in infancy.     

Hand, Arm, and Facial Actions of Young Infants to a Social and Nonsocial Stimulus

Do 9-15-week-old infants produce differentially organized hand and arm actions in relation to affective states when presented with social and nonsocial stimuli? This question was examined by observing 8 infants longitudinally. They were observed when facing their active and passive mother and an active and passive doll during 4 visits at biweekly intervals. Videotapes were coded in real time using the following measures: Vocalization, Gaze, and Gaze Avert; for face, Smiling, Distressed, and Neutral; for hands, Pointing, Open, Curled, and Closed; and for arms, Extended and At Side. Co-occurrence and lag sequential analyses showed that hand actions were organized with other infant actions to form unique behavioral linkages in each of the 4 conditions. The implications of these findings for the development of nonverbal communication are discussed.