Day by day, hour by hour: Naturalistic language input to infants. Issue 1 (10th August 2018)

• Record Type: Journal Article
• Authors: Bergelson, Elika; Amatuni, Andrei; Dailey, Shannon; Koorathota, Sharath; Tor, Shaelise
• Is Part Of: Developmental science. Volume 22:Issue 1(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-08-10
• Subjects: Developmental psychology -- Periodicals; Psychology, Comparative -- Periodicals; 155
• DOI: 10.1111/desc.12715
• Languages: English
• ISSNs: 1363-755X

Abstract

Abstract: Measurements of infants' quotidian experiences provide critical information about early development. However, the role of sampling methods in providing these measurements is rarely examined. Here we directly compare language input from hour‐long video‐recordings and daylong audio‐recordings within the same group of 44 infants at 6 and 7 months. We compared 12 measures of language quantity and lexical diversity, talker variability, utterance‐type, and object presence, finding moderate correlations across recording‐types. However, video‐recordings generally featured far denser noun input across these measures compared to the daylong audio‐recordings, more akin to 'peak' audio hours (though not as high in talkers and word‐types). Although audio‐recordings captured ~10 times more awake‐time than videos, the noun input in them was only 2–4 times greater. Notably, whether we compared videos to daylong audio‐recordings or peak audio times, videos featured relatively fewer declaratives and more questions; furthermore, the most common video‐recorded nouns were less consistent across families than the top audio‐recording nouns were. Thus, hour‐long videos and daylong audio‐recordings revealed fairly divergent pictures of the language infants hear and learn from in their daily lives. We suggest that short video‐recordings provide a dense and somewhat different sample of infants' language experiences, rather than a typical one, and should be used cautiously for extrapolation about common words, talkers, utterance‐types, and contexts at larger timescales. If theories of language development are to be held accountable to 'facts on the ground' from observational data, greater care is needed to unpack the ramifications of sampling methods of early language input. Abstract : We measured 44 infants' early noun input during free‐form interactions in hour‐long videos and daylong audio‐recordings. We found that videos were similar to 'peak' hours of the daylong audio‐recordings, and far denser than infants' typical interactions at the daylong scale. Furthermore, top nouns in audio‐recordings were more consistent across families than the top nouns in videos.