The impact of the home musical environment on infants’ language development

There is strong evidence that musical engagement influences children’s language development but little research has been carried out on the relationship between the home musical environment and language development in infancy. The current study assessed musical exposure at home (including parental singing) and language development in 64 infants (8.5–18 months). Results showed that the home musical environment significantly predicted gesture development. For a subgroup of infants’ below 12 months, both parental singing and overall home musical environment score significantly predicted word comprehension. These findings represent the first demonstration that an enriched musical environment in infancy can promote development of communication skills.     

Prolonged development of auditory skills: A role for perceptual anchoring?

Many auditory skills continue to develop beyond infancy and even into adolescence, but the factors underlying this prolonged development remain poorly understood. Of interest here is the contribution of on-line statistical learning of stimulus repetitions (anchoring) to the development of auditory spectral and temporal discrimination, as well as the potential contributions of auditory attention and working memory. Children, aged 6–13 years, as well as adults (age range: 21–33 years) were tested on auditory frequency and duration discrimination. Each type of discrimination was measured in two conditions (XAB and XXXAB) designed to afford different levels of anchoring by varying the number of repetitions of a standard stimulus (X) prior to the presentation of the test tone (A or B) in each trial. Auditory attention and working memory were also assessed. Whereas duration and frequency discrimination in either condition did not reach adult level prior to 11 years of age, the magnitude of the anchoring effect was similar across ages. These data suggest that perceptual anchoring matures prior to the attainment of adult-like discrimination thresholds. Likewise, neither attention nor working memory could account for the observed developmental trajectories. That auditory discrimination and anchoring follow dissociable developmental trajectories suggests that different factors might contribute to the development of each. We therefore conclude that although anchoring might be necessary for attaining good auditory discrimination, it does not account for the prolonged development of auditory frequency and duration discrimination in school-aged children.     

The development of language in genie: a case of language acquisition beyond the “critical period”

The present paper reports on a case of a now-16-year-old girl who for most of her life suffered an extreme degree of social isolation and experiential deprivation. It summarizes her language acquisition which is occurring past the hypothesized “critical period” and the implications of this language development as related to hemispheric maturation and the development of lateralization. The results of a series of dichotic listening tests administered to her are included.     

A life worth giving? The threshold for permissible withdrawal of life support from disabled newborn infants

When is it permissible to allow a newborn infant to die on the basis of their future quality of life? The prevailing official view is that treatment may be withdrawn only if the burdens in an infant's future life outweigh the benefits. In this paper I outline and defend an alternative view. On the Threshold View, treatment may be withdrawn from infants if their future well-being is below a threshold that is close to, but above the zero-point of well-being. I present four arguments in favor of the Threshold View, and identify and respond to several counter-arguments. I conclude that it is justifiable in some circumstances for parents and doctors to decide to allow an infant to die even though the infant's life would be worth living. The Threshold View provides a justification for treatment decisions that is more consistent, more robust, and potentially more practical than the standard view.     

The development of expert face processing: are infants sensitive to normal differences in second-order relational information?

Sensitivity to second-order relational information (i.e., spatial relations among features such as the distance between eyes) is a vital part of achieving expertise with face processing. Prior research is unclear on whether infants are sensitive to second-order differences seen in typical human populations. In the current experiments, we examined whether infants are sensitive to changes in the space between the eyes and between the nose and the mouth that are within the normal range of variability in Caucasian female faces. In Experiment 1, 7-month-olds detected these changes in second-order relational information. Experiment 2 extended this finding to 5-month-olds and also found that infants detect second-order relations in upright faces but not in inverted faces, thereby exhibiting an inversion effect that has been considered to be a hallmark of second-order relational processing during adulthood. These results suggest that infants as young as 5 months are sensitive to second-order relational changes that are within the normal range of human variability. They also indicate that at least rudimentary aspects of face processing expertise are available early in life.     

Quantity discrimination in Tenebrio molitor: evidence of numerosity discrimination in an invertebrate?

Numerosity discrimination, the ability to distinguish between sets with more and less items, is recognised as the foundation for higher numerical abilities. Understanding numerosity discrimination from a comparative perspective is hence pivotal in tracing the evolution of numerical representation systems. However, numerosity discrimination has been well studied only in vertebrates, where two innate systems of number representation have been described: an ‘analog magnitude system’ used to discriminate among numerosities by representing them as cardinal magnitudes and a ‘parallel individualisation system’ that allows precise discrimination among small arrays of items (≤4) by representing objects individually. We investigated the existence of quantity discrimination in an insect species (Tenebrio molitor) by using a spontaneous two-choice procedure in which males were exposed to substrates bearing odours from different numbers of females (≤4) in increasing numerosity ratios (1:4, 1:3 and 1:2). We show that males can discriminate sources of odours reflecting 1 versus 4 and 1 versus 3 females, but not 2 versus 4 or 1 versus 2, indicating that T. molitor males exhibit a marked preference for sources reflecting more female donors only when numerosity ratios are below 1:2. We discuss the functional significance of this finding and whether our pattern of results could be best explained by summation of a non-numerical continuous variable or by the existence of a numerosity discrimination mechanism with an operational signature ratio of 1:2.     

The development of expertise: animal models?

There is a continuing debate in the psychological literature between researchers who lean more toward learning theories of expertise development and those who lean more toward talent theories. However, the development of human expertise has not been open to direct experimental methods and will probably continue to elude experimentalists in the future. A promising alternative to direct experimental methods is to use human animal models, a possibility that researchers in expertise seem to have overlooked. However, there are studies in the animal behavior literature that address the development of nonhuman animal expertise without specifically referring to the topic as expertise. In the present study, the author discusses two nonhuman animal examples of expertise development that have been researched by ethologists. Nonhuman animal expertise development, unlike human expertise development, is subject to direct experimentation. The author thus recommends that researchers use nonhuman animals in their studies of expertise.     

Potentiation in young infants: The origin of the prior knowledge effect?

In two experiments with 6-month-old infants, we found that prior learning of an operant task (remembered for 2 weeks) mediated new learning of a modeling event (remembered for only 1 day) and increased its recall. Infants first learned to associate lever pressing with moving a toy train housed in a large box. One or 2 weeks later, three target actions were modeled on a hand puppet while the train box (a retrieval cue) was in view. Merely retrieving the train memory strengthened it, and simultaneously pairing its retrieved memory with the modeled actions potentiated their learning and recall. When paired 1 week later, deferred imitation increased from 1 day to 4 weeks; when paired 2 weeks later, it increased from 1 day to 6 weeks. The striking parallels between potentiated learning in infants and the prior knowledge effect in adults suggests that the prior knowledge effect originates in early infancy.     

The faculty of language: what's special about it?

We examine the question of which aspects of language are uniquely human and uniquely linguistic in light of recent suggestions by Hauser, Chomsky, and Fitch that the only such aspect is syntactic recursion, the rest of language being either specific to humans but not to language (e.g. words and concepts) or not specific to humans (e.g. speech perception). We find the hypothesis problematic. It ignores the many aspects of grammar that are not recursive, such as phonology, morphology, case, agreement, and many properties of words. It is inconsistent with the anatomy and neural control of the human vocal tract. And it is weakened by experiments suggesting that speech perception cannot be reduced to primate audition, that word learning cannot be reduced to fact learning, and that at least one gene involved in speech and language was evolutionarily selected in the human lineage but is not specific to recursion. The recursion-only claim, we suggest, is motivated by Chomsky's recent approach to syntax, the Minimalist Program, which de-emphasizes the same aspects of language. The approach, however, is sufficiently problematic that it cannot be used to support claims about evolution. We contest related arguments that language is not an adaptation, namely that it is "perfect," non-redundant, unusable in any partial form, and badly designed for communication. The hypothesis that language is a complex adaptation for communication which evolved piecemeal avoids all these problems.     

Can language prime culture in Hispanics? The differential impact of self‐construals in predicting intention to use a condom

The highly influential theory of planned behavior suggests that norms and attitudes predict an important antecedent of behavior: intention. Cross-cultural research suggests that culturally influenced self-construals can be primed and differentially affect behaviors that are influenced by norms and attitudes. The purpose of this experiment was twofold: (1) To investigate whether language functions as a prime for culture in Hispanics, and (2) if so, if norms and attitudes differentially predict condom use intention. Fluent English-Spanish bilingual participants (N = 145) of Mexican descent were randomly assigned to answer questionnaires in English and Spanish. Subjective norms and private evaluations towards condom use were assessed and their relative strength in predicting condom use intention was evaluated. Results suggest that language can prime culture and affect the relative accessibility of culture-relevant norms and self-construals in Hispanics. Moreover, consistent with our expectations, norms and attitudes differentially predicted condom use intention.     

Mothers of high-risk infants: Is their initial use of early intervention a predictor of later coping?

In a program for high-risk and handicapped infants that began at hospital discharge, mothers' initial use of intervention visits was investigated as a predictor of maternal functioning 9 months later. Measures included ventilation and advice seeking in the first month and 9-month maternal mood, coping, HOME scores, and use of intervention. Early ventilation and advice seeking were related significantly to mothers' self-reported confusion, but not to staff ratings of maternal mood. No significant relationships were found between early use of intervention and later coping, HOME scores, or use of intervention. Results are discussed in terms of mothers' generally good adaptation and the need for caution in drawing conclusions from their behavior soon after the birth of a high-risk or handicapped child.     

Developmental shift in the discrimination of vowel contrasts in bilingual infants: is the distributional account all there is to it?

A shift from language‐general to language‐specific sound discrimination abilities has been largely attested in different populations of infants during the second half of the first year of life; however, data are still scarce regarding bilingual populations. Previous research with 4‐, 8‐ and 12‐month‐old Catalan‐Spanish bilingual infants had offered evidence of a U‐shaped pattern in their ability to discriminate a language‐specific vowel contrast. This research explores monolingual and bilingual 4‐ and 8‐month‐olds’ capacities to discriminate two common vowel contrasts: /o–u/ and /e–u/. All groups succeeded except 8‐month‐old bilinguals tested on the phonetically close /o–u/ contrast. Discrimination was not facilitated when talker and token variability were reduced. A U‐shaped pattern was again found when data from an additional group of 12‐month‐olds were included. These results confirm bilinguals’ specific developmental pattern of perceptual reorganization for acoustically close vowels and challenge an interpretation merely based on a distributional account.     

Preterm birth enhances the contribution of mothers’ mind-mindedness to infants’ expressive language development: A longitudinal investigation

Maternal mind-mindedness has been shown to be a powerful predictor of many developmental outcomes and to buffer the impact of psychosocial risk conditions, but no study has investigated whether this parental feature might support child development in the presence of biological risk, such as preterm birth. The present study addresses this gap, by investigating whether early maternal mind-mindedness contributes to the growth of a child’s linguistic abilities in the following two years of life, and if the contribution of this maternal feature might be stronger in the presence of preterm birth. Forty mother–child dyads (twenty with a preterm infant) were followed longitudinally, with maternal mind-mindedness assessed at 14 months of age and child’s expressive linguistic abilities at 24 and 36 months through observational measures. Multilevel models showed that linguistic abilities increased from 24 to 36 months of age, but that this increase was stronger in full-term infants. Maternal mind-mindedness also contributed to this growth, playing a stronger role in preterm infants than in full-term infants. Altogether, these findings contribute more deeply to the understanding of language development in preterm infants and of the joint contribution made by biological risk and environmental factors; from a practical standpoint, they suggest the importance of addressing mother’s mind-mindedness in order to support child’s language development.     

Whose gaze will infants follow? The elicitation of gaze-following in 12-month-olds

Eighty-three 12-month-old infants faced a noisy, active, object for one minute, after which the object turned 45 degrees to the left or the right. Five conditions explored what object features elicited gaze-following behavior in the infants. In one condition, the object was an adult stranger. The other four conditions used a soft, brown, dog-sized, amorphously-shaped, asymmetrical novel object that varied along two dimensions theorized as central to the identification of intentional beings: facial features and contingently interactive behavior. Infants shifted their own attentional direction to match the orientation of the actor or object in every condition except the one in which the object lacked both a face and contingently interactive behavior. Infants’‘gaze’-following behavior in general, therefore, appears to have been driven selectively by a particular configuration of behavioral and morphological characteristics, specifically those theorized as underlying attributions of intentionality rather than attributions of person per se.     

Coping with dialects from birth: Role of variability on infants’ early language development. Insights from Norwegian dialects

Previous research suggests that exposure to accent variability can affect toddlers’ familiar word recognition and word comprehension. The current preregistered study addressed the gap in knowledge on early language development in infants exposed to two dialects from birth and assessed the role of dialect similarity in infants’ word recognition and comprehension. A 12-month-old Norwegian-learning infants, exposed to native Norwegian parents speaking the same or two Norwegian dialects, took part in two eye-tracking tasks, assessing familiar word form recognition and word comprehension. Their parents’ speech was assessed for similarity by native Norwegian speakers. First, in contrast to previous research, our results revealed no listening preference for words over nonwords in both monodialectal and bidialectal infants, suggesting potential language-specific differences in the onset of word recognition. Second, the results showed evidence for word comprehension in monodialectal infants, but not in bidialectal infants, suggesting that exposure to dialectal variability impacts early word acquisition. Third, perceptual similarity between parental dialects tendentially facilitated bidialectal infants’ word recognition and comprehension. Forth, the results revealed a strong correlation between the raters and parents’ assessment of similarity between dialects, indicating that parental estimations can be reliably used to assess infants’ speech variability at home. Finally, our results revealed a strong relationship between word recognition and comprehension in monodialectal infants and the absence of such a relationship in bidialectal infants, suggesting that either these two skills do not necessarily align in infants exposed to more variable input, or that the alignment might occur at a later stage.     

The auditory redundant signals effect: An influence of number of stimuli or number of percepts?

In two experiments, we examined simple reaction times (RTs) for detection of the onsets and offsets of auditory stimuli. Both experiments assessed the redundant signals effect (RSE), which is traditionally defined as the reduction in RT associated with the presentation of two redundant stimuli, rather than a single stimulus. In Experiment 1, with two identical tones presented via headphones to the left ear, right ear, or both, no RSE was found in responding to tone onsets, but a large RSE was found in responding to their offsets. In Experiment 2, with a pure tone and white noise as the two stimulus alternatives, RSEs were found for responding to both onsets and offsets. The results support the notion that the occurrence of an RSE depends on the number of percepts, rather than the number of stimuli, and on the requirement to respond to stimulus onsets versus offsets. The parallel grains model (Miller & Ulrich, 2003) provides one possible account of this pattern of results.     

The effects of mothers' teasing: Do Japanese infants read their mothers' play intention in teasing?

The focus of this study was whether an infant can understand the playful intention in the mother's teasing behaviour. The mother's teasing behaviour can elicit playful interaction with the infant on the one hand, or can result in the infant's distress. In other words, teasing may function as the turning-point in mother-infant interaction. Thus it was hypothesized that the consequence of mothers' teasing behaviour would be positive or negative depending on the success or failure in communication of both mothers' play intention with play signs and infants' interpretation of the play signs. Subjects were 20 mothers and their infants aged from 10 to 13 months (M = 11 months) who were observed during 10 minutes of free play with toys that evoke minor surprise and/or fearfulness. Results showed that about one-third of mothers' teasing behaviour elicited the infant's enjoyment. Especially, mothers' playful teasing accompanied by a smile or laugh led most successfully to infant enjoyment. In contrast, mothers' pretence teasing elicited no particular response from infants. These data suggest that around their first birthday infants develop some understanding of the play intention latent in mothers' teasing behaviour.