The scope of infants' early object word extensions

Area of Science:

• Developmental Psychology
• Cognitive Science
• Linguistics

Background:

• Infants' understanding of object words by 6-9 months is established, but the scope of this comprehension remains unclear.
• Research questions whether infants treat object words as unique identifiers (proper nouns) or general category labels (common nouns).

Purpose of the Study:

• To investigate whether infants differentiate between individual- and category-scope word understanding.
• To determine the developmental timeline for comprehending both types of word scopes in early infancy.

Main Methods:

• Experiment 1: Assessed 6-month-olds' comprehension of a proper name ('Mommy').
• Experiment 2: Examined 6- and 9-month-olds' understanding of both proper names ('Mommy') and common nouns ('hand', 'ball').
• Experiment 3: Tested 12- to 15-month-olds' comprehension of individual ('Fido') and category ('dog') labels for the same pet.

Main Results:

• 6-month-olds comprehended 'Mommy' as an individual-specific term.
• 6- and 9-month-olds understood both individual-specific and category-extending labels.
• 12- to 15-month-olds demonstrated comprehension of both individual and category word scopes for the same object.

Conclusions:

• Infants possess the capacity to understand both individual- and category-scope words early in development.
• Neither lexical type appears to be a privileged starting point for infant word learning.
• Cross-situational learning and conceptual biases likely contribute to infants' acquisition of diverse word types.