Infants' Statistical Summary Processing of Tone Distributions

Abstract

Infants and adults are known to utilize statistical learning mechanisms to find structure in a variety of perceptual signals, including language (Saffran, Aslin, & Newport, 1996). Adults also form statistical summary (or “gist”) representations of auditory stimuli (Piazza et al., 2013). However, it is not known if infants deploy gist processing to learn about their environment. To begin investigating whether infants’ statistical summary abilities play a role in early learning, we explored infants’ processing of tone distributions. Investigating this question is complex, not only because the tones used in this study are microtones and are not found in Western music, but also because previous studies have not explored this form of statistical learning in infants. To choose optimal stimuli for the infant study, a small experiment was run using adult participants. Then, in the headturn preference procedure (HPP), infants had the opportunity to form a “gist” representation of a rapid 64-tone sequence and then, at test, determine if a new sequence was sampled from the same or different statistical distribution (defined either by mean or variability of the tones). This is the first study to investigate infants’ gist processing of auditory stimuli, and the findings suggest that infants can recognize, and prefer, a positive directional shift in either mean pitch or variance in distributions despite condition and block. Implications for utilizing gist processing to navigate a multifaceted social world are discussed.