Infancy最新文献

What environmental regularities support infant communicative learning from social interactions? We propose that infants allocate their attention toward and learn from external events that are contingent on their own behaviors. We tested the robustness of the influence of contingency on communicative learning by using a non-biological stimulus, a remote-controlled car, as the social partner. The car approached infants and produced a speech sound either contingently to infants' vocalizations or on a yoked schedule. Two additional groups had an unfamiliar human experimenter as their social partner in contingent and yoked control conditions. We assessed whether infants formed expectations about their partner's responsiveness to their vocalizations. Expectations made based on contingent responsiveness would support the role of contingency in promoting plasticity in early communicative learning. Infants across all conditions increased their vocalization rates when their partner paused in responding, suggesting that they expected their vocalizations to influence their partners' behavior. Infants vocalized significantly more to the social partner than their caregiver if they received contingent rather than yoked responses from the social partner, regardless of if the partner was a human or non-biological agent. Contingent responses to prelinguistic vocalizations facilitated the formation of expectations for interactivity of social partners.

Daylong recordings provide an ecologically valid option for analyzing language input, and have become a central method for studying child language development. However, the vast majority of this work has been conducted in North America. We harnessed a unique collection of daylong recordings from Slovenian infants (age: 16–30 months, N = 40, 18 girls), and focus our attention on manually annotated measures of parentese (infant-directed speech with a higher pitch, slower tempo, and exaggerated intonation), conversational turns, infant words, and word combinations. Measures from daylong recordings showed large variation, but were comparable to previous studies with North American samples. Infants heard almost twice as much speech and parentese from mothers compared to fathers, but there were no differences in language input to boys and girls. Positive associations were found between the social-interactional features of language input (parentese, turn-taking) and infants' concurrent language production. Measures of child speech from daylong recordings were positively correlated with measures obtained through the Slovenian MacArthur-Bates Communicative Development Inventory. These results support the notion that the social-interactional features of parental language input are the foundation of infants' language skills, even in an environment where infants spend much of their waking hours in childcare settings, as they do in Slovenia.

Caregivers may perceive pointing as an indication of infants' readiness to learn, thereby increasing their tendency to label objects regardless of the infant's gesture type and context. This was investigated in this study by tracking 35 infants at home at the ages of 11 and 13 months and observing their interactions with their mothers during object manipulation. We focused on four types of communicative gestures: typical giving gestures, gestures contingent on exploration, gestures contingent on play, and pointing. We analyzed maternal response tendencies, including affirmation, naming, discourse, and pretense. The results revealed that when infants reached the age of 13 months, they tripled their pointing production; in turn, the maternal response changed entirely, with naming becoming the preferred response to all types of gestures. Furthermore, when infants were 13 months old and offered an object contingent on play acts, mothers increased their pretense acts sevenfold. Based on the most informative responses to infants among those examined, we argue that an increase in the number of pointing gestures may gradually be associated with the establishment of the maternal perception that an infant is ready to learn and a subsequent increase in naming and pretense production by the mother.

Infants' use of pointing gestures to direct and share attention develops during the first 2 years of life. Shyness, defined as an approach-avoidance motivational conflict during social interactions, may influence infants’ use of pointing. Recent research distinguished between positive (gaze and/or head aversions while smiling) and non-positive (gaze and/or head aversions without smiling) shyness, which are related to different social and cognitive skills. We investigated whether positive and non-positive shyness in 12-month-old (n = 38; 15 girls) and 15-month-old (n = 45; 15 girls) infants were associated with their production of pointing gestures. Infants' expressions of shyness were observed during a social-exposure task in which the infant entered the laboratory room in their parent's arms and was welcomed by an unfamiliar person who provided attention and compliments. Infants' pointing was measured with a pointing task involving three stimuli: pleasant, unpleasant, and neutral. Positive shyness was positively associated with overall pointing at 15 months, especially in combination with high levels of non-positive shyness. In addition, infants who displayed more non-positive shyness pointed more frequently to direct the attention of the social partner to an unpleasant (vs. neutral) stimulus at both ages. Results indicate that shyness influences the early use of pointing to emotionally charged stimuli.

Memory develops across the course of the first years of life and is influenced by daily experiences, such as exposure to media like books and television. Memory as tapped by Deferred imitation (DI) requires that toddlers form a representation of the target actions that they can later use to reproduce the actions and in addition to measuring memory for real live events, it can also be used to measure memory for events viewed through media. Toddlers are frequently exposed to multiple forms of digital media in addition to more traditional forms of picture book reading. In a within-subjects design, memory was assessed with a DI task in 2-year-olds (n = 89) using the Frankfurt Imitation Test. Deferred imitation was assessed after live and video demonstrations. Parents completed a survey about children's media use. Picture book reading for less than 30 min a day predicted lower memory scores for actions demonstrated live. Watching video content for more than 1 h a day predicted lower memory scores for actions demonstrated on video. Results are interpreted in terms of individual differences in experiences of traditional and digital media and the development of symbolic understanding.

Mother-infant interactions are co-regulated and provide the foundation for mother-infant relationship quality. The implications of maternal depression and contextual demands (i.e., reinstating the interaction following maternal unavailability and vocalized infant distress) on observationally coded co-regulation in mother-infant dyads (n = 40) at 4-months was investigated. Associations among co-regulation patterns and mother-infant relationship quality was also examined. Dyads participated in Still-Face (SF) and Separation (SP) procedures, with periods of maternal emotional and physical unavailability. Co-regulation was captured using the Revised Relational Coding System. Relationship quality was examined using the Emotional Availability Scales. Dyads in the depressed group had significantly more unilateral exchanges than the non-depressed group following the SF and SP perturbations. The depressed group also had significantly more distress vocalizations during the SP perturbation than the non-depressed group. Co-regulation in the depressed group was less disrupted by the SF perturbation. Positive relationship quality dimensions (maternal sensitivity, structuring, and infant responsiveness) were associated with more symmetrical and less unilateral co-regulation regardless of the interaction period. There were also context-specific results pertaining to patterns of co-regulation and associated maternal hostility and infant responsiveness. Results highlight co-regulatory differences in depressed mothers and their infants and how these differences are exacerbated by contextual demands.

Turn-taking is a universal pattern of human conversations characterized by a fast exchange of turns between speakers and an avoidance of overlaps. Language is embedded in this conversational skill acquired well before it during infancy, through everyday interactions with caregivers. The earliness of this skill and its link with language allows us to test whether social environment shapes early language development. We therefore study turn-taking perception of 6-month-old infants by measuring their gazes during video presentation of three different conversational situations where the turn is explicitly given, normally taken or taken with an overlap. We studied 51 infants to cover several family and infant characteristics: infants' sex, presence of siblings, and family socioeconomic status (SES). We found that infants looked more at the second speaker when she overlapped the first speaker than in the other situations, but not all infants were equally sensitive. Indeed, infants from high-SES families reacted differently to the three situations, while infants from the two lower SES categories did not. Also, only singletons reacted differently by looking more at the second speaker after the overlapping and turn-giving situations, and not after the turn-taking situation. Our results emphasize the importance of early social experiences on language development.

Adult studies have shown that observed interpersonal touch provides crucial information about others' emotional states. Yet, despite the unique communicative function of touch during development, very little is known about infants' sensitivity to the emotional valence of observed touches. To investigate this issue, we measured facial electromyographic (EMG) activity in response to positive (caress) and negative (scratches) observed touches in a sample of 11-month-old infants. Facial EMG activity was measured over the zygomaticus major (ZM) and corrugator supercilii muscles, respectively involved in positive (i.e., smiling) and negative (i.e., frowning) facial expressions. Results have shown distinct activations of the ZM during the observation of scratches and caresses. In particular, significantly greater activation of the ZM (smiling muscle) emerged specifically in response to the observation of caresses compared to scratches. Our finding suggests that, in infancy, observed affective touches can evoke emotional facial reactions.

Toddlers prefer to learn from familiar adults, particularly their caregivers, and perform better on word learning tasks when taught by caregivers than by strangers. However, it remains unclear why toddlers learn better from caregivers than from strangers. One possibility is that toddlers are more receptive to learning from individuals whom they have found to be engaging in previous interactions. The current study tested whether toddlers learn more from an unfamiliar adult who was previously engaging than from an unfamiliar adult who was previously unengaging. Toddlers (27–29 months, N = 40) were taught labels for novel objects by two different experimenters. Prior to word learning, toddlers watched pre-recorded videos of one experimenter utilizing engaging behaviors (i.e., using infant-directed speech, gestures, eye contact, and positive affect) and one experimenter utilizing unengaging behaviors (i.e., using adult-directed speech, no gestures, no eye contact, and neutral affect). Both experimenters were equally engaging during labeling. Word learning was then tested using a looking-while-listening paradigm. The results of linear mixed-effects model, cluster-based permutation, and growth curve analyses suggest heightened performance for words that were taught by the experimenter who was previously engaging. These results begin to reveal the kinds of social experiences that promote success in early word learning.

Cognitive control is a predictor of later-life outcomes and may underpin higher order executive processes. The present study examines the development of early cognitive control during the first 24-month. We evaluated a tablet-based assessment of cognitive control among infants aged 18- and 24-month. We also examined concurrent and longitudinal associations between attentional disengagement, general cognitive skills and cognitive control. Participants (N = 60, 30 female) completed the tablet-task at 18- and 24-month of age. Attentional disengagement and general cognitive development were assessed at 5-, 8-, 12-, 18- and 24-month using an eye-tracking measure and the Mullen Scales of Early Learning (MSEL), respectively. The cognitive control task demonstrated good internal consistency, sensitivity to age-related change in performance and stable individual differences. No associations were found between infant cognitive control and MSEL scores longitudinally or concurrently. The eye-tracking task revealed that slower attentional disengagement at 8-month, but faster disengagement at 18-month, predicted higher cognitive control scores at 24-month. This task may represent a useful tool for measuring emergent cognitive control. The multifaceted relationship between attention and infant cognitive control suggests that the rapid development of the attentional system in infancy results in distinct attentional skills, at different ages, being relevant for cognitive control development.