In a series of experiments, pregnant women read the same children's book aloud daily during their ninth month of pregnancy. Three days after birth, their infants listened to the same story, read either by the infant's own mother or by another baby's mother. Tests indicated that the newborns paid greater attention to the recording of their own mother's voice. The newborns also responded less when their mothers read an unfamiliar story than when they read the familiar one. Which of the following ideas can be inferred from the paragraph?
1) Infants cannot detect differences between voices until they are several months old.
2) Women's voices have the same effect on babies as do men's voices.
3) Babies are capable of hearing, learning, and remembering while in the womb.