Defining the Role Of Language in Infants' Object Categorization with Eye-tracking Paradigms

Summary

Here we present a protocol for familiarization-test paradigms which provide a direct test of infant categorization and help to define the role of language in early category learning.

Abstract

Assessing infant category learning is a challenging but vital aspect of studying infant cognition. By employing a familiarization-test paradigm, we straightforwardly measure infants’ success in learning a novel category while relying only on their looking behavior. Moreover, the paradigm can directly measure the impact of different auditory signals on the infant categorization across a range of ages. For instance, we assessed how 2-year-olds learn categories in a variety of labeling environments: in our task, 2-year-olds successfully learned categories when all exemplars were labeled or the first two exemplars were labeled, but they failed to categorize when no exemplars were labeled or only the final two exemplars were labeled. To determine infants’ success in such tasks, researchers can examine both the overall preference displayed by infants in each condition and infants’ pattern of looking over the course of the test phase, using an eye-tracker to provide fine-grained time-course data. Thus, we present a powerful paradigm for identifying the role of language, or any auditory signal, in infants’ object category learning.

Introduction

Categorization is a fundamental building block of human cognition: infants’ categorization abilities emerge early in infancy and become increasingly sophisticated with age.^1,2,3 Research has also revealed a powerful role for language in infant categorization: from 3 months of age, infants learn categories more successfully when category exemplars are paired with language.^4,5,6 Moreover, by the end of the first year, infants are attuned to the role of count noun labels in c....

Protocol

All methods described here have been approved by the Northwestern University Institutional Review Board.

1. Stimuli Creation

NOTE: The visual stimuli (see Figure 1) used in the representative design reported below were originally developed in Havy and Waxman (2016)¹⁸ and are available for download at https://osf.io/n6uy8/.

1. To create a new continuous category, first design a pair of novel digital image.......

Discussion

Here, we present a procedure for evaluating the role of labeling in categorization. By presenting 2-year-olds with a realistic mix of labeled and unlabeled exemplars, we demonstrate that very young children are capable of learning in semi-supervised environments, extending work with adults and older children^24,25. Thus, this method offers a resolution to the paradox posed above: if even a few labeled exemplars can spark category learning, then labels can be both .......

Materials

Name	Company	Catalog Number	Comments
Final Cut Pro X	Apple	N/A	Video editing, composition software
MorphX	Norrkross	N/A	Image-morphing software
PhotoShop	Adobe	N/A	Image-editing software
R	R Core Team	N/A	Statistical analysis software
T60XL Eyetracker	Tobii Pro	Discontinued	Large, arm-mounted eyetracker suitable for work with infants and children
Tobii Pro Studio	Tobii Pro	N/A	Software directing eyetracker display, data collection