DEVELOPMENTAL-CHANGES IN THE INCIDENCE AND LIKELIHOOD OF SIMULTANEOUSTALK DURING THE FIRST 2 YEARS - A QUESTION OF FUNCTION

Global tendencies for the relative absence of covocalization (simultan eous talk) have been identified in both conversations between adult pa rtners and conversations between mothers and their infants; in each ca se, the alternating mode in which one partner speaks at a time is pred ominant. The present investigation examined the timing of the partners ' talk in mother-infant engagements over infant age to determine wheth er: (a) variations occur in the incidence of the alternating mode; and (b) variations occur in the extent to which the alternating mode pred ominates. Conversations involving a total of 48 mothers and their infa nts aged from 0;3 to 2;0 were investigated at each of eight infant age s (0;3, 0;6, 0;9, I;0, I;3, I;6, I;9 and 2;0). The results indicated t hat, within a global tendency for the relative absence of covocalizati on, there was: (a) a curvilinear tendency for the incidence of covocal ization to decrease over the first Is months, and then to increase; an d (b) a linear tendency for the extent to which the alternating mode p redominates to increase over age. These changes are interpreted as ref lecting the facilitative effects of covocalization in the case of youn g preverbal infants, and the need for the alternating, turn-taking pat tern to pre-dominate as mutual comprehension becomes possible in conve rsations between mothers and their older infants.