In the first ManyBabies project, we replicated a robust finding from developmental literature: infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). IDS is characterized by a higher pitch, greater pitch excursions, and shorter utterances when compared to ADS. Exposure to IDS has been shown to improve word segmentation and word learning. We asked if infants have a preference for IDS, and how this preference varies across age, native language background, and method.
Sixty-nine labs, summing 2,329 infants (range: 3-15 months-old) from 16 countries participated. We focused on three primary methods for assessing infants’ interest: single-screen central fixation, eye tracking, and the head-turn preference procedure (HPP).
We confirmed the existence of an IDS preference in infant listeners. We also found that it increases across development (magnitude of 0.05 SDs per month), suggesting a modulation by experience, maturation, or both. We found a preference for North America English (NAE) IDS even among participants whose native language or dialect was not NAE.
Lastly, we found a stronger effect with the HPP than with the central-fixation or eye-tracking approaches. This engagement might be linked to the greater effort required by HPP.
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ManyBabies Consortium (2020). Quantifying sources of variability in infancy research using the infant-directed speech preference. Advances in Methods and Practices in Psychological Science, 3, 24-52. PsyArXiv Preprint
- MB1A: Infant-Directed Speech Preference in African Infants
- MB1B: Infant-Directed Speech Preference in Bilingual Infants
- MB1L: Longitudinal Vocabulary Follow-up
- MB1N: Native Languages Follow-up
- MB1T: Test-Retest Follow-up