Using a Pressure-Sensitive Pacifier Protocol, Infants Sometimes Had to Change

Multiple Choice

Using a pressure-sensitive pacifier protocol, infants sometimes had to change the pause between sucks to get the recording to switch to their own mother's voice. DeCasper and Fifer (1980) found that ________.

A) newborn infants who were three days old stopped sucking entirely in order to hear their own mother's voice
B) newborn infants who were three days old were able to alter their sucking in order to hear their own mother's voice
C) newborn infants who were at least three months old stopped sucking entirely in order to hear their own mother's voice
D) newborn infants who were at least three months old, but not earlier, were able to alter their sucking in order to hear their own mother's voice