Rapid gains in the speed and efficiency of word recognition by infants in the second year

Toward the end of the second year, during the period of rapid development in productive vocabulary known as the ‘‘vocabulary explosion,’’ infants also make dramatic gains in the speed and efficiency with which they are able to recognize familiar words in fluent speech. Here several studies using an on-line measure of speech processing by infants from 15 to 24 months of age are presented. In this research, an auditory-visual matching procedure, in which infants looked at two familiar pictures while hearing a target word that matched one of the pictures, was used. Monitoring infants’ eye movements from the onset of the target word, word recognition was assessed by measuring infants’ latency to look to the matching picture in response to the spoken word. These studies show that by the end of the second year, children are progressing toward the highly efficient performance of adults, using incomplete acoustic information to make rapid and accurate decisions about the identity of spoken words. [Work supported by NIMH.]