Adult word learning as a function of neighborhood density

Abstract

Previous studies exploring the influence of neighborhood density (ND) during adult word learning have largely relied on tasks designed for young, preliterate children. In order to examine effects of ND on adult word learning during an ecologically valid task, eight nonwords varying in neighborhood density (4 dense, 4 sparse) were taught to 50 typical adults in the context of a lecture. Half of the participants (n = 25) were solely exposed to the phonological forms of the nonwords, while the other half of the participants (n = 25) were exposed to both the phonological forms and orthographic representations. Results indicated that participants who only heard the nonwords learned more dense words than sparse words, similar to prior work. However, participants who heard as well as saw the nonwords learned dense words and sparse words to a similar degree, in addition to overall greater learning of sparse words. Thus, learning of sparse words can improve when orthographic information supplements the phonological information. An account of working memory is re-visited to interpret the results related to auditory and visual processing during lexical acquisition.