The acquisition of mental verbs: A systematic investigation of the first reference to mental state

It is generally recognized that the ability to contemplate and communicate about the knowledge, beliefs, and goals of oneself and others is a benchmark of human cognition. Yet, little is known about the beginnings of this ability, in large measure because methods for accurately assessing very young children's ability have been unavailable. Here we present the results of using a method of convergent analyses of naturally occurring speech to assess the young child's ability to contemplate and communicate about mental state. The first study describes the frequency and function of verbs of mental reference such as think and know in the speech of one child from 2;4 to 4;0. The second examines shorter samples of speech collected from 30 two-year-olds over a 6 month period. Results from both studies suggest that the earliest uses of mental verbs are for conversational functions rather than for mental reference. First attempts at mental reference begin to appear in some children's speech in the second half of the third year. Since most of the children studied exhibited the linguistic knowledge necessary to make reference to mental states, we conclude that the absence of such reference earlier suggests that still younger children lack awareness of such states, or at the very least, an understanding of their appropriateness as topics of conversation.