Universality and specificity in infant-directed speech: Pitch modifications as a function of infant age and sex in a tonal and non-tonal language

The aim of this study was to investigate the prosodic characteristics of infant-directed speech (IDS) to boys and girls in a tonal (Thai) and non-tonal (Australian English) language. Speech was collected from mothers speaking to infants at birth, and 3, 6, 9, and 12 months, and also to another adult. Mean-F₀, pitch range, and utterance slope-F₀ were extracted, and the integrity of the tonal information in Thai investigated. The age trends across the two languages differed for each of these measures but Australian English IDS was generally more exaggerated than Thai IDS. With respect to sex differences, Australian English mothers used higher mean-F₀, pitch range, and more rising utterances for girls than boys, but Thai mothers used more subdued mean-F₀ and more falling utterances for girls than boys. Despite variations in pitch modifications by Thai and Australian English mothers, overall IDS is more exaggerated than adult-directed speech (ADS) in both languages. Furthermore, tonal information in Thai was only slightly less identifiable in Thai IDS than Thai ADS. The universal features and language-specific differences in IDS are discussed in terms of facilitating infant socialization at younger ages, and language acquisition later in infancy.     

Infant-directed speech supports phonetic category learning in English and Japanese

Across the first year of life, infants show decreased sensitivity to phonetic differences not used in the native language [Werker, J. F., & Tees, R. C. (1984). Cross-language speech perception: evidence for perceptual reorganization during the first year of life. Infant Behaviour and Development, 7, 49-63]. In an artificial language learning manipulation, Maye, Werker, and Gerken [Maye, J., Werker, J. F., & Gerken, L. (2002). Infant sensitivity to distributional information can affect phonetic discrimination. Cognition, 82(3), B101-B111] found that infants change their speech sound categories as a function of the distributional properties of the input. For such a distributional learning mechanism to be functional, however, it is essential that the input speech contain distributional cues to support such perceptual learning. To test this, we recorded Japanese and English mothers teaching words to their infants. Acoustic analyses revealed language-specific differences in the distributions of the cues used by mothers (or cues present in the input) to distinguish the vowels. The robust availability of these cues in maternal speech adds support to the hypothesis that distributional learning is an important mechanism whereby infants establish native language phonetic categories.     

Consistency in maternal affect and positive vocalization over the first year of life

Consistency in parenting infants has positive developmental outcomes. Yet, the role of socioeconomic status (SES) in consistency of maternal behaviors is not well understood. We investigated individual-order continuity of maternal smile and laughter and positive vocalization from 6 to 12 months of age in 82 mother-infant dyads. Overall, individual differences in maternal smile and laughter, and positive vocalization were consistent across time. A multidimensional measure of SES moderated the association of maternal smile and laughter from 6 to 12 months, such that infants from lower SES families were vulnerable to unpredictable parenting - experiencing a lack of consistency in maternal smiles and laughter.     

Control of Trajectory Modifications in Target-Directed Reaching

Human reaching movements to fixed and displaced visual targets were recorded and compared with simulated movements generated by using a two-joint arm model based on the equilibrium-point (EP) hypothesis (λ model) of motor control (Feldman, 1986). The aim was to investigate the form of central control signals underlying these movements. According to this hypothesis, movements result from changes in control variables that shift the equilibrium position (EP) of the arm. At any time, muscle activations and forces will depend on the difference between the arm's EP and its actual position and on the limb's velocity. In this article, we suggest that the direction of EP shift in reaching is specified at the hand level, whereas the rate of EP shift may be specified at the hand or joint level. A common mechanism underlying reaching to fixed and displaced targets is proposed whereby the EP of the hand shifts in a straight line toward the present target. After the target is displaced, the direction of the hand EP shift is modified toward the second target. The results suggest that the rate of shift of the hand EP may be modified for movements in different parts of the work space. The model, with control signals that vary in a simple fashion over time, is able to generate the kinematic patterns observed empirically.     

Frontal brain electrical activity (EEG) and heart rate in response to affective infant-directed (ID) speech in 9-month-old infants

Many studies have shown that infants prefer infant-directed (ID) speech to adult-directed (AD) speech. ID speech functions to aid language learning, obtain and/or maintain an infant's attention, and create emotional communication between the infant and caregiver. We examined psychophysiological responses to ID speech that varied in affective content (i.e., love/comfort, surprise, fear) in a group of typically developing 9-month-old infants. Regional EEG and heart rate were collected continuously during stimulus presentation. We found the pattern of overall frontal EEG power was linearly related to affective intensity of the ID speech, such that EEG power was greatest in response to fear, than surprise than love/comfort; this linear pattern was specific to the frontal region. We also noted that heart rate decelerated to ID speech independent of affective content. As well, infants who were reported by their mothers as temperamentally distressed tended to exhibit greater relative right frontal EEG activity during baseline and in response to affective ID speech, consistent with previous work with visual stimuli and extending it to the auditory modality. Findings are discussed in terms of how increases in frontal EEG power in response to different affective intensity may reflect the cognitive aspects of emotional processing across sensory domains in infancy.     

The effects of live parental infant-directed singing on infants,parents, and the parent-infant dyad: A systematic review of the literature

Singing to infants is widely accepted as an enjoyable, positive, and beneficial interaction between the parent and infant across cultures. Whilst the literature suggests that live infant-directed singing impacts the infant, the parent doing the singing and the dyad in powerful ways, no systematic review of the evidence has yet been conducted. To this end, this systematic review identified 21 studies that investigated the effect of live parental infant-directed singing. These impacts were categorized as either being directly related to the infant, the parent, or the parent-infant dyad. Three main themes – one for each of the impact categories considered – were identified using thematic analysis techniques; infant-directed singing impacts on: infants’ emotional regulation, provides validation of the parent’s role, and promotes affect attunement within the dyad. The findings reinforce the benefits of live parental infant-directed singing for all parties involved, particularly when parents sing to typically developing infants born at full term. In contrast, the findings were inconsistent for pre-term infants. The implications of these findings are discussed.     

Using principles of cognitive science to improve science learning in middle school: What works when and for whom?

Four principles of cognitive science were used to make systematic revisions in middle school science instructional modules from two kinds of curriculum: one popular textbook series and one popular hands‐on series (two modules each). Schools were randomly assigned to 1 of the 3 arms (cognitive science modifications with professional development, active control with professional development, or business‐as‐usual). Two cohorts of students were followed in each arm for each setting. There were significant benefits of the cognitive science intervention, but the nature of effects varied for the two settings and curricula. For the text‐based curriculum, positive effects of cognitive science modifications were concentrated in classrooms with lower proportions of underrepresented minority students. For the hands‐on curriculum, there were positive effects that were not linked to school composition. Participation in the active control did not significantly improve student learning. Implications for policy and research are discussed.     

Exploring Modifications to Individual Trauma-Focused PTSD Treatments in a Routine Care Setting: An Examination of Medical Records at a Veterans Health Administration PTSD Clinic

Clinicians in naturalistic settings regularly modify the delivery of trauma-focused treatments to enhance client engagement and retention. However, what types of modifications are made in clinical settings, why, and when, and their impact on client outcomes has seldom been examined. As an initial step to address this, the current study applied elements of the updated Framework for Reporting Adaptations and Modifications—Expanded (FRAME; Wilstey Stirman et al., 2019) to examine content-level modifications documented in the delivery of posttraumatic stress disorder (PTSD) treatment to veterans via medical records review in an urban PTSD clinic. Results indicated that the updated FRAME suited the data well, and that modifications occurred in most veteran–clinician pairs over the course of treatment. The four most common modifications documented were spreading (27%), repeating (24%), drift with return (22%), and integrating (21%). Three composite case examples are discussed that describe the application of the most common modifications observed in medical record documentation. This is an important first step toward understanding the real-world modifications of evidence-based trauma-focused interventions that in turn will lead to critical recommendations for improving treatment implementation.