Quantifying sources of variability in infancy research using the infant-directed speech preference

Abstract

The field of psychology has become increasingly concerned with issues related to methodology and replicability. Infancy researchers face specific challenges related to replicability: high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations, amongst other factors. Addressing these concerns, we report on a large-scale, multi-site study aimed at 1) assessing the overall replicability of a single theoretically-important phenomenon and 2) examining methodological, situational, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). Stimuli of mothers speaking to their infants and to an adult were created using semi-naturalistic laboratory-based audio recordings in North American English. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three commonly-used infant discrimination methods (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s *d*) was 0.35 [0.29 - 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together these findings replicate the infant-directed speech preference but suggest that its magnitude is modulated by development, native language experience, and testing procedure.

What Do North American Babies Hear? A large‐scale cross‐corpus analysis

“…All the data from this study are readily available for reanalysis by other researchers and for use in developing automatic labeling methods and we encourage such data re-use. This work also provides an example for how shared datasets with interoperable classification schema can provide more robust analyses than any single laboratories data alone; this is an important step forward in addressing replicability and reproducibility in psychology (ManyBabies Collaborative, 2017).…”

Early Language Experience in a Tseltal Mayan Village

“…In pursuing this topic, many researchers have fixed their sights on the speech addressed to children. In several languages, child-directed speech (CDS; speech designed for and directed toward a child recipient) has been demonstrated to be distinct from adult-directed speech (ADS) in that it is linguistically adapted for young listeners (e.g., Soderstrom, 2007), interactionally rich (Bruner, 1983), preferred by infants (ManyBabies Collaborative, 2017), and facilitates early word learning (Cartmill et al, 2013;Hoff, 2003;Rowe, 2008;Weisleder & Fernald, 2013).…”

Parent coaching increases conversational turns and advances infant language development

“…The first (11), examined data across 34 experiments and reported a robust effect size (Cohen's d = 0.72) for a preference of infant-over adult-directed speech by infants. The second, published by the ManyBabiesConsortium (12), involved studies from 67 laboratories across North America, Europe, and Asia, and reported a significant effect size across all studies (Cohen's d = 0.35).…”