How big is this sound? Crossmodal association between pitch and size in infants

We examined 4- and 6-month-old infants’ sensitivity to the perceptual association between pitch and object size. Crossmodal correspondence effects were observed in 6-month-old infants but not in younger infants, suggesting that experience and/or further maturation is needed to fully develop this crossmodal association.     

Infant distractibility from social events mediates the relation between maternal responsiveness and infant language outcomes

Research demonstrates that contingent and appropriate maternal responsiveness to infant requests and bids for attention leads to better language outcomes. Research also indicates that infants who are less distracted by irrelevant competing stimulation and attend efficiently to audiovisual social events (e.g., faces and voices) show better language outcomes. However, few studies have assessed relations between maternal responsiveness, infant attention to faces and voices, and distractibility, and how together these factors lead to early language outcomes. A newly developed audiovisual protocol, the Multisensory Attention Assessment Protocol (MAAP; Bahrick et al., 2018), allows researchers to examine individual differences in attention to faces and voices and distractibility, and to assess relations with other variables. At 12 months, infants (n = 79) in an ongoing longitudinal study participated in the MAAP to assess intersensory matching of synchronous faces and voices and attention to an irrelevant competing visual distractor event. They also were observed in a brief play interaction to assess infant bids for attention and maternal responsiveness (accept, redirect, or ignore). At 18 months, receptive and expressive language were assessed using the Mullen Scales of Early Learning. Several noteworthy findings emerged: 1) mothers were generally responsive, accepting 74% and redirecting 14% of infant bids, 2) infants who had a greater number of their bids redirected by mothers, and who had better intersensory matching of synchronous faces and voices, showed less attention to the distractor, and 3) infants who showed less attention to the distractor had better receptive language. Findings demonstrate that maternal redirecting of infant attention by mothers who are generally responsive may promote better infant attentional control (lower distractibility) which in turn predicts better receptive language in toddlers.     

The effects of maternal employment and non-maternal infant care on development at two and four years

Differences in maternal employment during children's first year of life and children's entry into non-maternal care before the age of 1 year failed to predict differences in cognitive and socioemotional development at 2 and 4 years of age, after family background variables were controlled. Two samples were studied: a population sample of 1100 Bermudian children and a smaller subsample of children most of whom were determined to be at risk for developmental problems. To assess the effects of maternal employment, we compared infants with mothers who worked 20 or more hours a week to infants with mothers who worked less than 20 hours a week. To assess the effects of entry into non-maternal care before the age of one, we compared infants who were placed in regular non-maternal care before the age of one versus infants who did not experience regular non-maternal care before the age of one. The results revealed that family background variables frequently predicted many child outcome measures in both the total sample and the smaller research sample. After controlling for family characteristics, no differences were found between children whose mothers worked 20 or more hours a week when they were infants and children with mothers who worked less than 20 hours a week in either sample. In addition, age of entry into non. maternal care before the age of one did not significantly predict any child outcome measures.     

Factors associated with the socioemotional development of preterm infants

Preterm birth is a risk factor for problems in interactions with others. We compared the difference in socioemotional development between hospital discharge and at six months of corrected age of infants born ≤32 weeks and assessed the impact of maternal and infantile factors on socioemotional development rate within a 6 month’s period. Mother-child dyads (n = 144) were assessed by the Mother-Baby Observation Protocol 0–6 months through a video microanalysis. Multivariate model was built. Neonatal, maternal and child factors were associated with interactive gaze, initiate contact, responsiveness, infantile vocalization, and thus contributed to the socioemocional development of preterm infants with their mothers.     

Eye tracking provides no evidence that young infants understand path obstruction

In two experiments with 47 4-month-olds, we investigated attention to key aspects of events in which an object moved along a partly occluded path that contained an obstruction. Infants were familiarized with a ball rolling behind an occluder to be revealed resting on an end wall, and on test trials an obstruction wall was placed in the ball's path. In Experiment 1, we did not find longer looking when the object appeared in an impossible location beyond the obstruction, and infants did not selectively fixate the object in this location. In Experiment 2, after rolling one or two balls, we measured infants' fixations of a two-object outcome with one ball in a novel but possible resting position and the other in a familiar but impossible location beyond the obstruction. Infants looked longer at the ball in the possible but novel location, likely reflecting a looking preference for location novelty. Thus we obtained no evidence that infants reasoned about obstruction and identified a violation on that basis.     

The effects of massage velocity on heart rate and heart rate variability in healthy infants: A randomized crossover study

BackgroundInfant massage, in which mothers stroke their infant’s skin slowly and gently, can cause pleasant sensations in the infant that can be affected by the velocity of massage. However, the massage velocity at which infants feel the most pleasant sensations remains unclear.ObjectiveTo investigate the effects of massage velocity on heart rate (HR) and HR variability (HRV) in healthy infants.MethodTwenty-two infant-mother dyads two to seven months of age were recruited. Mothers stroked their infant’s skin at three massage velocities (5.0, 7.5, and 10.0 cm/s) in a randomized order for 15 min. The rhythm of massage velocity was calculated according to the length of three body areas. The massage velocity of the mothers was regulated using a metronome. HR and HRV (high frequency [HF] and low frequency [LF]) were measured at rest and during massage for each velocity. The effects on pleasantness were evaluated using percent change in median baseline value compared with median values for the three massage velocities. Statistical analysis was performed using analysis of variance mixed effect models to exclude “period” and “carryover” effects during massage.ResultsWhen measuring HF, massage (7.5 cm/s) caused a significant increase in pleasantness compared with 10.0 cm/s (p = 0.04). The HR and LF/HF ratio were not significantly changed between velocities.ConclusionResults of this study suggested that a massage velocity of 7.5 cm/s was the most pleasant for infants. Future research should investigate the relationship between an infant massage by optimal velocity and infant development in longitudinal studies.     

Infants’ vocalizations at 6 months predict their productive vocabulary at one year

Long before their first words, children communicate by using speech-like vocalizations. These protophones might be indicative of infants’ later language development. We here examined infants’ (n = 56) early vocalizations at 6 months (vocal reactivity scale of the IBQ-R) as a predictor of their expressive and receptive language at 12 months (German version of the CDI). Regression analyses revealed vocalizations to significantly predict expressive, but not receptive language. Our findings in German-learning 6-month-olds extend previous predictive evidence of early vocalizations reported for older infants. Together these findings are informative in light of early assessments monitoring typical and atypical language development.     

Learning and development in neural networks--the importance of prior experience

Infants can discriminate between familiar and unfamiliar grammatical patterns expressed in a vocabulary that is distinct from that used earlier during familiarization (Cognition 70(2) (1999) 109; Science 283 (1999) 77). Various models have captured the data, although each required that discrimination be distinct, in terms of the computational process, from familiarization. This article describes a simple recurrent network (SRN), equipped only with the assumption that it should predict what comes next, which models the data without distinguishing between familiarization and discrimination. To accomplish this, the SRN requires pre-training on a range of sequences instantiating different structures and different vocabulary items to those used subsequently during familiarization and test. Pre-training enables the network to avoid replacing structure acquired during familiarization with structure experienced at test. An equivalent enabling condition may underpin infants' resistance to catastrophic interference between the different structures and vocabulary items to which they are exposed.     

Selection and inhibition in infancy: evidence from the spatial negative priming paradigm

We used a spatial negative priming (SNP) paradigm to examine visual selective attention in infants and adults using eye movements as the motor selection measure. In SNP, when a previously ignored location becomes the target to be selected, responses to it are impaired, providing a measure of inhibitory selection. Each trial consisted of a prime and a probe, separated by 67, 200, or 550 ms interstimulus intervals (ISIs). In the prime, a target was accompanied by a distractor. In the probe, the target appeared either in the location formerly occupied by the distractor (ignored repetition) or in another location (control). Adults exhibited the SNP effect in all three ISI conditions, producing slower saccade latencies on ignored repetition versus control trials. The SNP effect obtained for infants only under 550 and 200 ms ISI conditions. These results suggest that important developments in visual selection are rooted in emerging inhibitory mechanisms.