ACCOMMODATION IN MEAN F(0) DURING MOTHER-INFANT AND FATHER-INFANT VOCAL INTERACTIONS - A LONGITUDINAL CASE-STUDY

Reports that infants imitate the vocal pitch characteristics of adult caregivers (e.g. Lewis, 1936/1951) include Lieberman's (1967; Lieberma n, Ryalls & Rabson, 1982) claim that infants differentially adjust the ir vocal pitch or fundamental frequency (f(0)) towards that of their c aregivers, resulting in higher mean pitch when interacting with mother s than when interacting with fathers. However, a recent cross-sectiona l study of infants at ages 0;8 to 0;9 and 1;0 failed to find evidence of differential pitch adjustment toward male and female caregivers (Si egel, Cooper, Morgan & Brennesie-Sarshad, 1990). A more sensitive test of Lieberman's claims would be to use a longitudinal design, with spo ntaneous recording sessions repeated over many months. The current stu dy presents data from a longitudinal case study of an infant recorded at ages 0;3, 0;7, 0;10, 1;3 and 1;5 interacting with each of her paren ts in spontaneous play sessions and in isolated play. The infant in ou r study did not demonstrate significant adjustment of her vocal pitch in the direction of either parent. However, we did find evidence for c onsistent adjustment by the parents, in accord with the literature on infant-directed speech and mother-infant dyadic interactions, which su ggest that the parents adjusted their behaviour to suit the infant mor e than vice versa.