Before they start to talk, babies can recognize the difference between two and three entities, a new study suggests.
Most 7-month-old infants match the number of faces that they see talking—whether two or three—with the number of voices that they hear, without any training, say Kerry E. Jordan and Elizabeth M. Brannon, psychologists at Duke University in Durham, N.C. The researchers studied 20 babies who were held by their mothers in front of two video monitors. One screen showed two women mouthing the word "look" and the other showed three women doing the same. All five women spoke repeatedly for 1 minute. A loudspeaker played either two or three women's voices saying "look" in synchrony with one of the video images.