The breadth and specificity of 18-month-old's infant-initiated interactions in naturalistic home settings.

Infants actively initiate social interactions aiming to elicit different types of responses from other people. This study aimed to document a variety of communicative interactions initiated by 18-month-old Turkish infants from diverse SES (N = 43) with their caregivers in their natural home settings. The infant-initiated interactions such as use of deictic gestures (e.g., pointing, holdouts), action demonstrations, vocalizations, and non-specific play actions were coded from video recordings and classified into two categories as need-based and non-need-based. Need-based interactions were further classified as a) biological (e.g., feeding); b) socio-emotional (e.g., cuddling), and non-need-based interactions (i.e., communicative intentions) were coded as a) expressive, b) requestive; c) information/help-seeking; d) information-giving. Infant-initiated non-need-based (88%) interactions were more prevalent compared to need-based interactions (12%). Among the non-need-based interactions, 50% aimed at expressing or sharing attention or emotion, 26% aimed at requesting an object or an action, and 12% aimed at seeking information or help. Infant-initiated information-giving events were rare. We further investigated the effects of familial SES and infant sex, finding no effect of either on the number of infant-initiated interactions. These findings suggest that at 18 months, infants actively communicate with their social partners to fulfil their need-based and non-need-based motivations using a wide range of verbal and nonverbal behaviors, regardless of their sex and socio-economic background. This study thoroughly characterizes a wide and detailed range of infant-initiated spontaneous communicative bids in hard-to-access contexts (infants' daily lives at home) and with a traditionally underrepresented non-WEIRD population.

Correlates of infant pointing frequency in the first year.

This study examines the emergence of concurrent correlates of infant pointing frequency with the aim of contributing to its ontogenetic theories. We measured monthly from 8 to 12 months infants' (N = 56) index-finger pointing frequency along with several candidate correlates: (1) family socioeconomic status (SES), (2) mothers' pointing production, and (3) infants' point following to targets in front of and behind them. Results revealed that (1) infants increased their pointing frequency across age, but high-SES infants had a steeper increase, and a higher pointing frequency than low-SES infants from 10 months onward, (2) maternal pointing frequency was not associated with infant pointing frequency at any age, (3) infants' point following abilities to targets behind their visual fields was positively associated with their pointing frequency at 12 months, after pointing had already emerged around 10 months. Findings suggest that family SES impacts infants' pointing development more generally, not just through maternal pointing. The association between pointing and following points to targets behind, but not in front, suggests that a higher level of referential understanding emerges after, and perhaps through the production of pointing.

Relation of infants' and mothers' pointing to infants' vocabulary measured directly and with parental reports.

Infants' and parents' pointing gestures predict infants' concurrent and prospective language development. Most studies have measured vocabulary size using parental reports. However, parents tend to underestimate or overestimate infants' vocabulary necessitating the use of direct measures alongside parent reports. The present study examined whether mothers' index-finger pointing, and infants' whole-hand and index-finger pointing at 14 months associate with infants' receptive and expressive vocabulary based on parental reports and directly measured lexical processing efficiency (LPE) concurrently at 14 months and prospectively at 18 months. We used the decorated room paradigm to measure pointing frequency, the Turkish communicative development inventory I to measure infants' receptive vocabulary, Turkish communicative development inventory II to measure their expressive vocabulary, and the Looking-While-Listening (LWL) task to measure LPE. At 14 months, 34 mother-infant dyads, and at 18 months, 30 dyads were included in the analyses. We found that only infants' index-finger pointing frequency at 14 months predicted their LPE (both reaction time and accuracy) prospectively at 18 months but not concurrently at 14 months. Neither maternal pointing nor infants' pointing predicted their receptive and expressive vocabulary based on indirect measurement. The results extend the evidence on the relation between index-finger pointing and language development to a more direct measure of vocabulary.