"Do you know what I think?": a cross-linguistic investigation of children's understanding of mental state words

Two studies were conducted to: (1) investigate children’s developing understanding of mental state words , specifically “think” and “know,” and (2) explore possible differences between U.S. English-speaking and Brazilian Portuguese-speaking children in their understanding of these words. Brazilian Portuguese is of interest because it has two words for “think” (one indicating a lesser degree of certainty, ‘achar,’ and another indicating the process of thinking, ‘pensar’) and two words for “know” (one indicating knowing a fact, ‘saber,’ and another indicating knowing a person, ‘conhecer’). Predictions were that there would be developmental changes in the understanding of these words and that having such distinctions marked in their language would help Brazilian children in the process of acquiring a conceptual understanding of “think” and “know.” In Study 1, 48 English-speaking children, divided into three age groups (21⁄2, 31⁄2, and 41⁄2) participated in a series of tasks during which the degree of certainty about the identity of an object was varied. Children were asked “Do you know that this is a .... or do you think that this is a ....?” In Study 2, 32 Brazilian Portuguese-speaking and 32 English-speaking children in each of 3 age groups (4, 5, and 6) saw a series of videotaped scenarios during which the two senses of “know” and the two senses of “think” were indicated by novel words. Participants were asked to interpret the novel words. Children also were asked metalinguistic questions regarding whether each pair of words differed in meaning. Results suggest that a complete understanding of these mental state words starts emerging at age 4 and that an understanding of “know” may precede an understanding of “think.” The effects of language were less than anticipated. The two senses of “think” and “know” that were tested may be represented conceptually by U.S. children even if they are not marked in the language. Nonetheless, having the distinctions marked in the language appear to increase older children’s awareness of the distinctions at a metalinguistic level.