Infants Extract Frequency Distributions from Variable Approximate Numerical Information

Abstract

Previous research shows that infants represent approximate number: After habituation to a constant numerosity (e.g., eight dots), 6‐month‐old infants dishabituate to a novel numerosity (e.g., 16 dots). However, numerical information in the real world is far more variable and rarely offers repeated presentations of a single quantity. Instead, we often encounter quantities in the form of distributions around a central tendency. It remains unknown whether infants can represent frequency distributions from this type of distributed numerical input. Here, we asked whether 6‐month‐old infants can represent distributions of large approximate numerosities. In two experiments, we first familiarized infants to sequences of dot collections with varying numerosities. For half the infants, the sequence contained a unimodal frequency distribution, with numerosities centered around a single mean, and for the other half, it contained a bimodal frequency distribution of numerosities with two numerical peaks. We then tested infants with alternating or constant numerosities. Infants who had been familiarized to a unimodal distribution looked longer at alternating numerosities than constant numerosities (experiments 1 and 2), whereas infants who had been familiarized to a bimodal distribution looked longer at constant numerosities (Exp. 2). These findings suggest that infants can spontaneously extract frequency distributions from distributed numerical input.