Emerging sensitivity to the timing and structure of protoconversation in early infancy.

Thirty-six 2-, 4-, and 6-month-old infants were videotaped while interacting with a female adult stranger engaging in either organized or disorganized 1-min peekaboo games. Two-month-old infants gazed and smiled equally at the stranger, regardless of the relative organization of the peekaboo game. In contrast, 4- and 6-month-old infants smiled significantly more and gazed significantly less in the organized peekaboo condition than in the disorganized peekaboo condition. These results suggest that from a diffuse sensitivity to the presence of a social partner, infants by 4 months develop a new sensitivity to the narrative envelope of protoconversation, in particular the timing and the structure of social exchanges scaffolded by adults. These observations are interpreted as evidence of developing social expectations in the first 6 months of life. This early development is viewed as announcing and preparing the communicative competence that blossoms by the end of the 1st year.