Examining the link between productive vocabulary and the shape bias: An ERP study

It is during a child’s second year that the rate of word learning increases drastically and they start to pay more attention to the property of shape when categorizing new objects. The present study set out to investigate the relationship between productive vocabulary size and the shape bias when children learn novel words. In order to better understand the neural mechanisms behind this process, event related brain potentials (ERPs) were recorded in an experiment with a group of 14 twenty-month olds. They were shown a series of real and novel picture/word pairs presented as a whole picture, a cluster of details or a black silhouette. After associations were learned, the objects were paired with the wrong names to see if a difference between congruent and incongruent presentations as indexed by N400 amplitudes could be discerned. The N400 is a component that is known to reflect the mechanisms underlying semantic integration and signifies that learning has taken place. Results showed that subjects with high productive vocabularies displayed an N400 incongruity effect for silhouette presentations (that represent shape) for both real words and pseudowords, indicating that children in the second year with large productive vocabularies show a sensitivity to shape when learning associations between new words and their referents