An image is worth a thousand words: why nouns tend to dominate verbs in early word learning.

Nouns are generally easier to learn than verbs (e.g., Bornstein, 2005; Bornstein et al., 2004; Gentner, 1982; Maguire, Hirsh-Pasek, & Golinkoff, 2006). Yet, verbs appear in children's earliest vocabularies, creating a seeming paradox. This paper examines one hypothesis about the difference between noun and verb acquisition. Perhaps the advantage nouns have is not a function of grammatical form class but rather related to a word's imageability. Here, word imageability ratings and form class (nouns and verbs) were correlated with age of acquisition according to the MacArthur-Bates Communicative Development Inventory (CDI) (Fenson et al., 1994). CDI age of acquisition was negatively correlated with words' imageability ratings. Further, a word's imageability contributes to the variance of the word's age of acquisition above and beyond form class, suggesting that at the beginning of word learning, imageability might be a driving factor.