Infants often protest the activities of their caregivers, and this particular social interaction may provide an important window on early communication and its development. This study used naturalistic methods to investigate the development of vocal protests. Fifteen mother-infant dyads at each of 5 ages, from 3 to 18 months, were observed at…

Acoustic properties of the cries of 14 infants were evaluated at both 2 and 4 weeks of age when the infants were lying in a supine position and when they were sitting upright in a car seat. In the upright position, infants' breathing was more rapid and showed less individual variability. The fundamental frequency of their cries increased in the…

Examined differences in acoustic characteristics of cries, both early and late, within a prolonged crying bout. Results indicated that late cries appeared to result from a smaller number of factors than did early cries. Results support notions that crying bouts settle into a regular cry with acoustic features matching a theoretical model of cry…