Tuesday, February 14, 2006

Babies Match Voices to Faces by the Numbers

Even seven-month-olds, who weigh in at around twenty pounds and might just be learning to crawl, can tell how many people are talking based on the number of voices they hear:
Neuroscientists Kerry Jordan and Elizabeth Brannon had previously shown that rhesus monkeys have a natural ability to match the number of voices they hear to the number of individuals they expect to see. When presented with a soundtrack of "coo" sounds, the monkeys chose to look at a picture containing the same number of fellow monkey faces. If the monkeys heard two coos, for example, they preferred to look at a picture of two monkeys rather than three and vice versa. The researchers expected the same to be true of human babies.

. . . .

The 20 seven-month-old infants in the study spent an average of nearly 22 seconds looking at the numerically appropriate video compared to just more than 14 seconds looking at the numerically wrong video. This represented 59.2 percent of their total time looking--nearly exactly the same percentage of time that the 20 rhesus monkeys spent looking at the video with the right number of monkeys. "This spontaneous matching of [numbers] across [sight and sound] supports the contention that human infants, human adults and nonhuman primates share at least one common nonverbal numerical representational system," the researchers conclude. Their report on these findings appears in this week's Proceedings of the National Academies of Science.
Link. Next up: a study asking whether babies can tell the difference, by sound alone, between quail and Alexander Hamilton.

Indexed by tags science, babies, infants, sound, math, maths, counting, voices.


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