Arias-Trejo, N. 1 & Plunkett, K. 2
1 Facultad de Psicologia, UNniversidad Nacional Autonoma de Mexico, UNAM
2 Dept. of Experimental Psychology, University of Oxford, United Kingdom
Exposure to prior related words facilitates subsequent word processing in school-age children and adults (Nation & Snowling, 1999; Neely, 1991). Infants are sensitive to word-world associations at least as early as their first birthday; however, virtually nothing is known about infants’ knowledge of word-word associations which eventually form the basis of the network of meanings underlying the adult semantic system. We investigated infants’ word associations using the Inter-modal Preferential Looking task. Experiment 1 measures 18- and 21-month-olds’ visual preferences for a target over a distracter object when exposed to pairs of semantically and associatively related or unrelated words. In order to evaluate the impact of the prime word itself, priming is also tested when the target object is not labelled. Experiment 2 compares two types of lexical-semantic relationship, associative and taxonomic at 21 and 24 months of age. The results indicated a semantic-associative priming effect for 21- but not for 18-month-olds. Eighteen-month-olds responded equally well to target names, regardless of their prior exposure to a related or an unrelated word. In contrast, 21-month-olds identified the target referent only in the condition in which they heard related-named pairs of words. Moreover, unrelated words interfered with linguistic target identification for 21-month-olds. Experiment 2 finds that both types of lexical relations, taxonomic and thematic, have been established at 24 months of age. These data indicate that words are associated in the early lexicon. Infants as early as 21 months of age establish a word-word relationship between semantic-associative word pairs. Furthermore, unrelated words inhibit referent identification. Older infants exhibited a priming effect in both associative and taxonomic conditions, pointing to the formation of lexical semantic networks driven by different relations. In conclusion, by their second birthday, infants have begun to construct a lexical-semantic system based on relations and have moved beyond an independent listing of lexical entries.