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Infants between 12 and 21 days of age can imitate both facial and manual gestures; this behavior cannot be explained in terms of either conditioning or innate releasing mechanisms. Such imitation implies that human neonates can equate their own unseen behaviors with gestures they see others perform.
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Toddlers' combinatorial abilities were examined over several behavioral domains as a function of age (20 and 27 months) and task demands (familiarity of components, length of combinations, complexity of combinations, centered/decentered focus of action, behavioral domain). 6 specific domains were represented. Children's combinations were observed during elicited imitation in 4 of the domains (object play, pretense, social play, motor play) and spontaneous production in 2 others (language and peer-directed social overtures). Relative to younger children, older children produced more combinations of at least 2 or 3 discrete behaviors in every domain, including peer interaction, and fewer noncombinatorial behaviors. Consistent relations were also found across domains for production of combinations, that is, children who produced more combinations in one domain also did so in others. Finally, 4 of the 5 manipulated task demands proved to affect performance. Results are discussed in terms of possible age-related constraints on combinatorial skills that operate at a general, cross-domain level during toddlerhood.
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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.
OBJECTIVE: Research suggests that eating problems are often present by preadolescence, yet little is known about the age of emergence of these early eating disturbances or risk factors for these behaviors. Thus, we investigated the timing of onset of disturbed eating during childhood and the predictors of these behaviors. METHOD: These aims were addressed by following a sample of children and their parents (N = 216) for the first 5 years of the children's lives. RESULTS: Data suggested that the risk for emergence of inhibited eating, secretive eating, overeating, and vomiting increased annually through age 5. Maternal body dissatisfaction, internalization of the thin-ideal, dieting, bulimic symptoms, and maternal and paternal body mass prospectively predicted the emergence of childhood eating disturbances. Infant feeding behavior and body mass during the first month of life also predicted the emergence of these behaviors. DISCUSSION: Results suggest that eating disturbances emerge during childhood and may be a function of certain parental and child characteristics.
Behavioral state distribution in 19 preterm infants at term with good developmental prognosis was studied by 24-h video recordings. The preterm infants of shortest gestation had longer time awake and this was concentrated in the daytime. On classifying behavioral states by Prechtl's criteria, the preterm infants had a smaller amount of state 1 than healthy term infants; but a similar amount of state 5 in awake time. Preterm infants were thought to have accelerated development in terms of diurnal sleep-awake rhythm, and decelerated development in terms of the content of sleep manifested by the amount of state 1.
A major focus of theory building in nursing relates to further conceptualization of human-environmental interaction and multidimensional systems that support or do not support health. There is a growing body of knowledge regarding the newborn and his skills, and the transactions and interactions between the newborn and his environment. The newborn cannot be considered in isolation from his environment for it is this interaction with the environment that provides opportunities for organization of his behavior, physiologic functions, and regulatory processes. The caregiving environment and the newborn's interactions with this environment form the ecologic niche of the newborn; one that will enhance or impede the infant's behavioral differentiation and organization, early adaptations, later development, and the infant's interactions with his parents and other caregivers.
The interactions of 16 premature and 17 full-term infants and their mothers were studied at 6, 8, 10, and 14 months of age. The infants were matched on sex, maternal age, parity, and social class. Premature infants vocalized less, played less, and were more fretful than full-term infants of the same chronological age but looked at objects and looked around their environment more. These differences, with the exception of vocalization, disappeared by 14 months. Mothers of premature infants demonstrated more caretaking and affectionate behavior toward their infants. With increasing age the differences between groups decreased. Premature dyads experienced as much interaction as full-term dyads, but premature mothers were not constant over the period under study in the amount of time they spend in the same room as their infants. Mothers responded to the developmental level of their infants. Premature infants behaved increasingly like full-term infants as they grew older.
Infants' development of speech begins with a language-universal pattern of production that eventually becomes language specific. One mechanism contributing to this change is vocal imitation. The present study was undertaken to examine developmental change in infants' vocalizations in response to adults' vowels at 12, 16, and 20 weeks of age and test for vocal imitation. Two methodological aspects of the experiment are noteworthy: (a) three different vowel stimuli (/a/, /i/, and /u/) were videotaped and presented to infants by machine so that the adult model could not artifactually influence infant utterances, and (b) infants' vocalizations were analyzed both physically, using computerized spectrographic techniques, and perceptually by trained phoneticians who transcribed the utterances. The spectrographic analyses revealed a developmental change in the production of vowels. Infants' vowel categories become more separated in vowel space from 12 to 20 weeks of age. Moreover, vocal imitation was documented, infants listening to a particular vowel produced vocalizations resembling that vowel. A hypothesis is advanced extending Kuhl's native language magnet (NLM) model to encompass infants' speech production. It is hypothesized that infants listening to ambient language store perceptually derived representations of the speech sounds they hear which in turn serve as targets for the production of speech utterances. NLM unifies previous findings on the effects of ambient language experience on infants' speech perception and the findings reported here that short-term laboratory experience with speech is sufficient to influence infants' speech production.
We tested the effects of various doses of the triazolobenzodiazepine alprazolam on behavioral, hormonal, and neurochemical responses of infant rhesus monkeys under three conditions of separation from their mothers: alone, in the presence of a human who stared at them, and in the presence of a human who avoided eye contact. Alprazolam affected stress-induced responses in all three of these classes. Unrelated to its effects on the stress response, alprazolam appears to reduce the function of brain dopamine systems.
Genes influence the development of anxiety disorders, but the specific loci involved are not known. Genetic association studies of anxiety disorders are complicated by the complexity of the phenotypes and the difficulty in identifying appropriate candidate loci. We have begun to examine the genetics of behavioral inhibition to the unfamiliar (BI), a heritable temperamental predisposition that is a developmental and familial risk factor for panic and phobic disorders. Specific loci associated with homologous phenotypes in mouse models provide compelling candidate genes for human BI. We conducted family-based association analyses of BI using four genes derived from genetic studies of mouse models with features of behavioral inhibition. The sample included families of 72 children classified as inhibited by structured behavioral assessments. We observed modest evidence of association (P = 0.05) between BI and the glutamic acid decarboxylase gene (65 kDA isoform), which encodes an enzyme involved in GABA synthesis. No significant evidence of association was observed for the genes encoding the adenosine A(1A) receptor, the adenosine A(2A) receptor, or preproenkephalin. This study illustrates the potential utility of using candidate genes derived from mouse models to dissect the genetic basis of BI, a possible intermediate phenotype for panic and phobic disorders.
Ainsworth's description of attachment patterns in the Strange Situation is one of the best known and most enduring descriptive insights in developmental psychology. Yet attachment theorists have paid little attention to whether ABC classifications represent a true taxonomy or to mechanisms that might produce truly distinct patterns of attachment. This comment focuses on three questions. Does attachment theory require distinct patterns of attachment? How can taxonomic analysis contribute to an understanding of individual differences in attachment security? And are attachment theorists asking the right questions? The authors conclude that attachment theory is indifferent to the structure (taxonomic or dimensional) of individual differences. Nonetheless, taxonomic search methods can make important contributions to attachment study if research is broadened to include secure base behavior in naturalistic settings.
The present study explored the relationship between nonverbal IQ and restricted and repetitive behaviors (RRBs) in 830 children with Autism Spectrum Disorders. The role of chronological age as a moderator of this relationship was also investigated. For many behaviors, there was a significant interaction between nonverbal IQ and chronological age, such that nonverbal IQ (NVIQ) was more strongly related to the prevalence of RRBs in older children. For the majority of such behaviors (e.g. repetitive use of objects, hand and finger mannerisms), RRB prevalence was negatively associated with NVIQ. However, the prevalence of certain behaviors (e.g. circumscribed interests) showed positive relationships with NVIQ, which provides some support for the idea of different classes of RRBs. For the severity of different RRBs, there were several significant effects for age and NVIQ, but few interactions.
Previous studies have shown that adults respond faster and more reliably to bimodal compared to unimodal localization cues. The current study investigated for the first time the development of audiovisual (A-V) integration in spatial localization behavior in infants between 1 and 10 months of age. We observed infants' head and eye movements in response to auditory, visual, or both kinds of stimuli presented either 25 degrees or 45 degrees to the right or left of midline. Infants under 8 months of age intermittently showed response latencies significantly faster toward audiovisual targets than toward either auditory or visual targets alone They did so, however, without exhibiting a reliable violation of the Race Model, suggesting that probability summation alone could explain the faster bimodal response. In contrast, infants between 8 and 10 months of age exhibited bimodal response latencies significantly faster than unimodal latencies for both eccentricity conditions and their latencies violated the Race Model at 25 degrees eccentricity. In addition to this main finding, we found age-dependent eccentricity and modality effects on response latencies. Together, these findings suggest that audiovisual integration emerges late in the first year of life and are consistent with neurophysiological findings from multisensory sites in the superior colliculus of infant monkeys showing that multisensory enhancement of responsiveness is not present at birth but emerges later in life.
The postoperative development of nonverbal communication was studied in 29 children, aged 18.2 (SD = 11.54) months, who underwent multilobar resection or hemispherectomy for intractable symptomatic infantile spasms (IS). Using the Early Social Communication Scale, the IS subjects had little, if any, social interaction, joint attention or behavior regulation before surgery. After a mean follow-up of 24 months, most of the children continued to have delayed nonverbal communication skills compared to normal children. Seizure-related, surgical and cognitive factors were unrelated to the postsurgical development of nonverbal communication. The children with right-sided surgery had a statistically significant increase in the use of social interaction but not in other gestural behaviors. Removal of the frontal lobe was not related to the nonverbal communication outcome. The study's findings suggest that impaired use of nonverbal communication might be a feature of surgically treated children with medically intractable IS.
The reduplicative babbling of five French- and five English-learning infants was examined for evidence of language-specific rhythmic patterns. Three types of patterns were examined: final-syllable lengthening, timing of nonfinal syllables, and number of syllables per utterance. Both English and French exhibit final-syllable lengthening but, because of variable word stress, English tends to lengthen nonfinal stressed syllables, as well as final ones. Thus French final-syllable lengthening is more salient because it is the only regular source of lengthening. There is also some indication that the magnitude of final syllable lengthening is greater in French than in English. In addition, French nonfinal syllables, which are not subject to English variable word stress, are generally equal in length, whereas English tends to have more irregularly timed nonfinal syllables. Finally, French breath-groups often contain as many as four to six syllables, whereas intervals between stressed syllables in English rarely contain more than three syllables. The reduplicative babbling of the French and American infants showed characteristics of the ambient language. In particular, the babbling of the French infants showed a significantly higher percentage of final-syllable lengthening than that of the American infants. The magnitude of their final-syllable lengthening was also greater. The French infants also produced significantly more reduplicative babbles that were four or more syllables in length. Finally, the nonfinal syllables of the French infants tended to be more regularly timed than those of the American infants, although this pattern emerged only in the later stage of the infants' reduplicative babbles.