Grant: Discovery Grants Program - Individual

The proposed research program examines the developmental mechanisms which drive children's spoken word recognition toward a mature state. Spoken word recognition in the adult literature is presumed to be a discriminative process. The speech input activates all similarly sounding words in a listener's lexicon (a similarity neighborhood) and words compete for recognition. Words that reside in dense neighborhoods (i.e., have many similarly sounding neighbors) are recognized more slowly and less accurately than those residing in sparse neighborhoods. Lexical representations and lexical organization are based on segments or phonemes, and this does not vary with the size of a word's neighborhood or the position of information within a word. Less is known about the development of spoken word recognition in early through middle childhood. Children's lexicons are smaller than adults and more dynamic as vocabulary knowledge continues to grow substantially past the initial vocabulary growth spurt. The proposed program of research aims to explore the role of increased neighborhood density in driving segmental representation, processing, and organization in young children's spoken word recognition. The role of increasing neighborhood density is also examined in relation to the development of children's phonological awareness abilities, and a training experiment is included to test the causal nature of this relationship. The effects of density and phonotactic probabilities on young children's spoken word recognition and vocabulary acquisition are examined toward a better understanding of these influences and to test if each can be differentiated, as in the adult behavioral data. The proposed program of research also examines whether different measures purporting to evaluate the quality of phonological representations form a unitary construct that is stable over time and predictive of growth in phonological awareness and reading. The findings from the proposed studies have implications for better understanding language development and its role in reading acquisition and will be of interest to those in the fields of language development and impairments, reading acquisition, and reading disabilities.