Number words, quantifiers, and principles of word learning

How do children learn the meanings of words like many and five? Although much is known about the mechanisms that underlie children's acquisition of nouns and verbs, considerably less is understood of how children begin to learn the meanings of words that refer to sets (e. g., number words and quantifiers). Here we argue that children's acquisition of quantity expressions relies on learning mechanisms typically associated with learning content words. In particular, we argue that the Whole Object Assumption and the Principle of Contrast are special cases of more general principles that guide not just the acquisition of nouns and verbs, but also the acquisition and interpretation of number words and quantifiers. (C) 2011 John Wiley & Sons, Ltd. WIREs Cogn Sci 2011 2 639-645 DOI: 10.1002/wcs.140