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Younger Infants (younger + infant)
Selected AbstractsIntersensory redundancy facilitates discrimination of tempo in 3-month-old infantsDEVELOPMENTAL PSYCHOBIOLOGY, Issue 4 2002Lorraine E. Bahrick Abstract L. Bahrick and R. Lickliter (2000) proposed an intersensory redundancy hypothesis that states that information presented redundantly and in temporal synchrony across two or more sensory modalities selectively recruits infant attention and facilitates perceptual learning more effectively than does the same information presented unimodally. In support of this view, they found that 5-month-old infants were able to differentiate between two complex rhythms when they were presented bimodally, but not unimodally. The present study extended our test of the intersensory redundancy hypothesis to younger infants and to a different amodal property. Three-month-olds' sensitivity to the amodal property of tempo was investigated. Results replicated and extended those of Bahrick and Lickliter, demonstrating that infants could discriminate a change in tempo following bimodal, but not unimodal, habituation. It appears that when infants are first learning to differentiate an amodal stimulus property, discrimination is facilitated by intersensory redundancy and attenuated under conditions of unimodal stimulation. © 2002 Wiley Periodicals, Inc. Dev Psychobiol 41: 352,363, 2002. Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/dev.10049 [source] Bayes nets and babies: infants' developing statistical reasoning abilities and their representation of causal knowledgeDEVELOPMENTAL SCIENCE, Issue 3 2007David M. Sobel A fundamental assumption of the causal graphical model framework is the Markov assumption, which posits that learners can discriminate between two events that are dependent because of a direct causal relation between them and two events that are independent conditional on the value of another event(s). Sobel and Kirkham (2006) demonstrated that 8-month-old infants registered conditional independence information among a sequence of events; infants responded according to the Markov assumption in such a way that was inconsistent with models that rely on simple calculations of associative strength. The present experiment extends these findings to younger infants, and demonstrates that such responses potentially develop during the second half of the first year of life. These data are discussed in terms of a developmental trajectory between associative mechanisms and causal graphical models as representations of infants' causal and statistical learning. [source] Object individuation and event mapping: developmental changes in infants' use of featural informationDEVELOPMENTAL SCIENCE, Issue 1 2002Teresa Wilcox The present research examined the development of 4.5- to 7.5-month-old infants' ability to map different-features occlusion events using a simplified event-mapping task. In this task, infants saw a different-features (i.e. egg-column) event followed by a display containing either one object or two objects. Experiments 1 and 2 assessed infants' ability to judge whether the egg-column event was consistent with a subsequent one-column display. Experiments 3 and 4 examined infants' ability to judge whether the objects seen in the egg-column event and those seen in a subsequent display were consistent in their featural composition. At 7.5 and 5.5 months, but not at 4.5 months, the infants successfully mapped the egg-column event onto the one-column display. However, the 7.5- and 5.5-month-olds differed in whether they mapped the featural properties of those objects. Whereas the 7.5-month-olds responded as if they expected to see two specific objects, an egg and a column, in the final display the 5.5-month-olds responded as if they simply expected to see ,two objects'. Additional results revealed, however, that when spatiotemporal information specified the presence of two objects, 5.5-month-olds succeeded at tagging the objects as being featurally distinct, although they still failed to attach more specific information about what those differences were. Reasons for why the younger infants had difficulty integrating featural information into their object representations were discussed. [source] The Role of Verbal Repetition in the Development of Infant Speech Preferences From 4 to 14 Months of AgeINFANCY, Issue 2 2009Gerald W. McRoberts Four experiments investigated infants' preferences for age-appropriate and age-inappropriate infant-directed speech (IDS) over adult-directed speech (ADS). Two initial experiments showed that 6-, 10-, and 14-month-olds preferred IDS directed toward younger infants, and 4-, 8-, 10-, and 14-month-olds, but not 6-month-olds, preferred IDS directed toward older infants. In Experiment 3. 6-month-olds preferred IDS directed toward older infants when the frequency of repeated utterances matched IDS to younger infants. In Experiment 4, 6-month-olds preferred repeated IDS utterances over the same IDS utterances organized without repetition. Attention to repeated utterances precedes word segmentation and sensitivity to statistical cues in continuous speech, and might play a role in the discovery of these and other aspects of linguistic structure. [source] The Development of Affect Specificity in Infants' Use of Emotion CuesINFANCY, Issue 5 2008Nicole Gendler Martin This study examined the emergence of affect specificity in infancy. In this study, infants received verbal and facial signals of 2 different, negatively valenced emotions (fear and sadness) as well as neutral affect via a television monitor to determine if they could make qualitative distinctions among emotions of the same valence. Twenty 12- to 14-month-olds and 20 16- to 18-month-olds were examined. Results suggested that younger infants showed no evidence of referential specificity, as they responded similarly to both the target and distracter toys, and showed no evidence of affect specificity, showing no difference in play between affect conditions. Older infants, in contrast, showed evidence both of referential and affect specificity. With respect to affect specificity, 16- to 18-month-olds touched the target toy less in the fear condition than in the sad condition and showed a larger proportion of negative facial expressions in the sad condition versus the fear condition. These findings suggest a developmental emergence after 15 months of age for affect specificity in relating emotional messages to objects. [source] Modeling Age Differences in Infant Category LearningINFANCY, Issue 2 2004Thomas R. Shultz We used an encoder version of cascade correlation to simulate Younger and Cohen's (1983, 1986) finding that 10-month-olds recover attention on the basis of correlations among stimulus features, but 4- and 7-month-olds recover attention on the basis of stimulus features. We captured these effects by varying the score threshold parameter in cascade correlation, which controls how deeply training patterns are learned. When networks learned deeply, they showed more error to uncorrelated than to correlated test patterns, indicating that they abstracted correlations during familiarization. When prevented from learning deeply, networks decreased error during familiarization and showed as much error to correlated as to uncorrelated tests but less than to test items with novel features, indicating that they learned features but not correlations among features. Our explanation is that older infants learn more from the same exposure than do younger infants. Unlike previous explanations that postulate unspecified qualitative shifts in processing with age, our explanation focuses on quantitatively deeper learning with increasing age. Finally, we provide some new empirical evidence to support this explanation. [source] Leukotriene synthesis during respiratory syncytial virus bronchiolitis: Influence of age and atopy,PEDIATRIC PULMONOLOGY, Issue 4 2005Giovanni Piedimonte MD Abstract Respiratory syncytial virus (RSV) infection is the most common cause of bronchiolitis in infants and an important risk factor for the development of recurrent wheezing and asthma. Cysteinyl leukotrienes were implicated in the pathophysiology of these diseases, and are being targeted for their diagnosis and therapy. We measured urinary leukotriene E4 (LTE4) in infants with RSV bronchiolitis in comparison with controls without respiratory infection, and investigated whether medical and family history, age, and passive exposure to tobacco smoke are related to urinary leukotriene excretion. We studied 33 infants with bronchiolitis and 25 controls, 1,12 months of age. Demographic and historical data were obtained from informed-consent forms and questionnaires completed by the parents. RSV was detected in nasal secretions by enzyme-linked immunoassay. Urine samples were collected on day of admission and were analyzed for LTE4 with an enzyme-linked immunoassay. Urinary LTE4 was 8-fold higher in infants with bronchiolitis than in controls. Leukotriene excretion was significantly higher in infected infants <6 months of age with a medical history of eczema or dry cough and/or family history of asthma. Multivariate analysis revealed that eczema and dry cough are independently associated with high LTE4 excretion during bronchiolitis. Exposure to tobacco smoke did not affect urinary LTE4. Our study shows that leukotriene synthesis during bronchiolitis is particularly elevated in younger infants with an atopic/asthmatic background. Urinary LTE4 may become a valuable, noninvasive marker for the identification of patients who will benefit most from therapy with leukotriene modifiers for management of bronchiolitis. Pediatr Pulmonol. © 2005 Wiley-Liss, Inc. [source] Nutritional rickets and z scores for height in the United Arab Emirates: To D or not to D?PEDIATRICS INTERNATIONAL, Issue 4 2008Jaishen Rajah Abstract Background: Vitamin D deficiency is still prevalent worldwide, including the Middle East. A cohort of patients with nutritional rickets was treated with vitamin D2 (ergocalciferol) alone. After this intervention, patients were followed to document changes in z scores for height after treatment. The secondary aim was to determine the proportion of affected children who had vitamin D deficiency or calcium deficiency. Methods: Z score for height was calculated as the difference between the observed value and the median value, divided by the SD of the population. Z scores were compared in patients before and after treatment. Results: The improvement in z score after treatment was 0.86 ± 0.95. The 95% confidence interval for the mean difference was 1.32,0.40 (t = 3.95, P < 0.001). With a diagnostic cut-off for 25 hydroxyvitamin D3 (25D) deficiency of <25 nmol/L, only half were diagnosed with severe vitamin D deficiency. The remaining patients had presumable calcium deficiency. The alkaline phosphatase (ALP) was negatively correlated to z scores, implying that higher ALP concentrations predicted severe bone disease (lower z scores). The variables 25D and age were moderately and positively correlated (Pearson's r = 0.59, 95%CI: 0.15,0.84; P = 0.01), indicating that younger infants had the lowest 25D levels. Conclusion: Vitamin D alone was efficient in resolving radiological and biochemical disturbances as well as improving z scores for height in a cohort of children with nutritional rickets, which included patients with 25D deficiency as well as calcium deficiency. The results support the hypothesis of the interplay and continuum of 25D deficiency and calcium deficiency in the pathogenesis of rickets. [source] Begging for information: mother,offspring food sharing among wild Bornean orangutansAMERICAN JOURNAL OF PRIMATOLOGY, Issue 6 2008Adrian V. Jaeggi Abstract Transfer of solid food from mothers or other adults to dependent offspring is commonly observed in various primate species and both nutritional and informational benefits have been proposed to explain the function of such food sharing. Predictions from these hypotheses are tested using observational data on wild orangutans (Pongo pygmaeus wurmbii) at Tuanan, Central Borneo, Indonesia. In 1,145,hr of focal observation and 458 recorded food interactions between four pairs of females with offspring it was found that virtually all transfers were initiated by the offspring and that younger infants solicited food more often and did so for a greater variety of items than older offspring. All offspring primarily solicited food that was difficult to process, i.e., inaccessible to them. Furthermore, the amount of food solicitation was negatively correlated with ecological competence. Hence food sharing seemed to be related to an offspring's skill level, as suggested by the informational hypothesis. In contrast, offspring did not solicit high-quality items more than low-quality items and food sharing did not peak around the age of weaning, as predicted by the nutritional hypothesis. Mothers were usually passively tolerant, allowing offspring to take food but hardly ever provisioned. Parent,offspring conflict concerning food sharing was only observed well after weaning. Thus, by taking food directly from the mother, young orangutans were able to obtain information about the affordances and nutritional value of food items that were otherwise out of their reach and could familiarize themselves with the mother's diet. In species such as orangutans or other apes, characterized by a broad diet that requires extractive foraging, informational food transfer may be vital for an immature to acquire complex feeding skills and adult diet. Am. J. Primatol. 70:533,541, 2008. © 2008 Wiley-Liss, Inc. [source] Milk composition varies in relation to the presence and abundance of Balantidium coli in the mother in captive rhesus macaques (Macaca mulatta)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 6 2007Katherine Hinde Abstract Primate infants require extensive maternal investment, and lactation is the most expensive aspect of this investment. However, the relationship between maternal condition and milk composition has been largely uninvestigated in primates. To better understand this relationship, I collected mid-lactation milk samples from 46 captive multiparous rhesus macaques (Macaca mulatta) at the Caribbean Primate Research Center, Sabana Seca Field Station, Puerto Rico. The maternal variables assessed were age, weight, weight for crown,rump length (CRL), and presence of parasites. Additionally the analysis included infant age, weight, and sex. Protein concentration in milk showed little interindividual variation, whereas fat had a high variance. Mothers without the lower intestinal parasite Balantidium coli had a significantly higher fat concentration in milk than mothers with B. coli, but other parasite species (Trichuris trichiura and Strongyloides fulleborni) were not associated with milk fat concentration. Females with younger infants had a higher fat concentration in their milk than mothers with older infants; however, the association between B. coli and milk fat remained significant after controlling for infant age. These results, obtained from a well fed captive population, indicate that even small differences among mothers are associated with milk composition. Am. J. Primatol. 69:625,634, 2007. © 2007 Wiley Liss, Inc. [source] Developmental Changes in Endogenous Control of Attention: The Role of Target Familiarity on Infants' Distraction LatencyCHILD DEVELOPMENT, Issue 6 2002Lisa M. Oakes This study evaluated the interactive effects of endogenous and exogenous influences on infants' attention allocation by assessing the role of target familiarity on distraction latency during object exploration. In Experiment 1 (N= 54), infants' distraction latencies as they investigated both familiar toys (ones they previously had seen in a familiarization procedure) and novel toys (ones they had not seen in the familiarization procedure) were assessed longitudinally at 6.5 and 9 months of age. In Experiment 2 (N= 32), infants' distraction latencies were assessed at either 6.5 or 10 months as they investigated either familiar or novel targets. In both experiments, older infants, but not younger infants, exhibited longer latencies as they investigated novel toys as compared with their latencies as they investigated familiar toys. These results are discussed in terms of developmental changes in the interactive effects of endogenous and exogenous factors controlling attention allocation. [source] Effect of formula thickened with reduced concentration of locust bean gum on gastroesophageal refluxACTA PAEDIATRICA, Issue 6 2007R Miyazawa Abstract Aim: Previous studies showed that HL-350, a formula thickened with a reduced concentration of locust bean gum, decreased frequent regurgitation in 4-month old infants with reflux. In this study, we investigated the effect of HL-350 in younger infants. Methods: We studied 20 infants less than 2 months old who had three or more episodes of regurgitation or vomiting per day. Ten infants (group A) were fed with HL-350 for the first week, and with control milk, HL-00, for the following week. The other 10 infants (group B) were fed in reverse order. Mothers recorded number of regurgitation episodes, feeding volume and time and number of bowel movements. To evaluate gastric emptying we measured antral cross sectional areas ultrasonographically at various time points after feeding. Results: The median number of regurgitation episodes decreased significantly with feeding of HL-350 (2.3/day) compared to feeding with control milk (5.2/day) (p = 0.00048). No significant difference was evident in feeding volume and time, body weight gain, or gastric emptying rate between HL-350 and control milk. Conclusion: HL-350 decreased the number of regurgitation episodes without affecting gastric emptying delay in very young infants with recurrent vomiting. [source] | |||||||||||||