Sign language, like spoken language, promotes object categorization in young hearing infants

Area of Science:

• Cognitive science
• Developmental psychology
• Linguistics

Background:

• The connection between language and cognition is a hallmark of human development, emerging early in infancy.
• Previous research has primarily focused on spoken language's impact on infant cognition.

Purpose of the Study:

• To investigate whether the early language-cognition link extends to sign language in infants.
• To determine if the linguistic components of sign language facilitate cognitive development in infants.
• To examine the developmental trajectory of this link in early infancy.

Main Methods:

• Familiarizing 4- to 6-month-old hearing infants with object categories using American Sign Language (ASL) or a control condition (pointing and gazing without language).
• Testing infants' ability to form object categories by presenting novel exemplars from familiar and new categories.
• Comparing categorization performance between infants exposed to ASL, spoken language, and the control condition.

Main Results:

• Four-month-old infants exposed to ASL successfully formed object categories, performing comparably to those exposed to spoken language.
• The facilitative effect on categorization was driven by the linguistic elements of ASL, not just gestures.
• By 5- to 6-months, the cognitive benefits of observing ASL for categorization diminished, unlike those from spoken language.

Conclusions:

• Infants' early language-cognition link is broad, encompassing visual sign languages.
• The linguistic modality (spoken vs. signed) influences the developmental timing of cognitive benefits.
• These findings highlight the plasticity and early emergence of language's role in shaping infant cognition.