Changes in visual object recognition precede the shape bias in early noun learning

Abstract

Two of the most formidable skills that characterize human beings are language and our prowess in visual object recognition. They may also be developmentally intertwined. Two experiments, a large sample cross-sectional study and a smaller sample 6-month longitudinal study of 18- to 24-month-olds, tested a hypothesized developmental link between changes in visual object representation and noun learning. Previous findings in visual object recognition indicate that children's ability to recognize common basic level categories from sparse structural shape representations of object shape emerges between the ages of 18 and 24 months, is related to noun vocabulary size, and is lacking in children with language delay. Other research shows in artificial noun learning tasks that during this same developmental period, young children systematically generalize object names by shape, that this shape bias predicts future noun learning, and is lacking in children with language delay. The two experiments examine the developmental relation between visual object recognition and the shape bias for the first time. The results show that developmental changes in visual object recognition systematically precede the emergence of the shape bias. The results suggest a developmental pathway in which early changes in visual object recognition that are themselves linked to category learning enable the discovery of higher-order regularities in category structure and thus the shape bias in novel noun learning tasks. The proposed developmental pathway has implications for understanding the role of specific experience in the development of both visual object recognition and the shape bias in early noun learning.

Keywords: development; infants; shape bias; visual object recognition; word learning.

Figure 1

Examples of stimulus sets used in the two experiments: (A) Shape bias – the named exemplar and three test objects matching in shape, surface texture, and color; (B) Caricature recognition – three sparse structural representations of the major parts of the characteristic shape of instances of common basic level categories; and (C) Object recognition – rich and typical toy representations of common basic level categories.

Figure 2

(A) For Experiment 1, and (B) for Experiment 2: mean proportion correct and standard errors in the Object recognition, Caricature recognition, and Shape bias tasks as a function of Vocabulary Size – Low (less than 55 nouns), Medium (56–125 nouns), and High (more than 125 nouns).

Figure 3

Scatter plot of criterion sessions for success in the Caricature recognition task and Shape Bias task for the 10 children in the 6-month longitudinal sample in Experiment 2.

Figure 4

Proposed developmental pathway and relevant experiences for the development of structural shape representations of common object categories and the shape bias in novel noun learning. Caricature recognition for specific basic level categories depends on the number and range of experienced instances and precedes and supports the development of the shape bias. The generalized ability to represent the structural shape of even novel things may be an intervening skill that may depend on the number and kind of known basic level categories.