When is a word a word: The development of word knowledge

The present study was conducted to determine if children’s increasing knowledge of wordness could be characterized as conforming to a system of successively mastered levels of understanding similar to acquisitions in a number of other cognitive domains. Stimuli differing on dimensions of word appearance and meaning were presented to first-, third-, fifth-, and seventh-grade students and to college students, who were required to identify whether or not each stimulus was a word and to indicate their certainty about these decisions. The validity of a hierarchical system of levels of understanding of wordness was confirmed. In addition, developmental predictions about accuracy and certainty were supported. It was concluded that children’s word knowledge is not unidimensional but involves several underlying component processes.