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10 SCIENTIFIC AMERICAN MIND December 2007/Januar y 2008

LANGUAGE

Understanding Baby TalkNew studies reveal the universal nature of the singsong way we talk to infantsNearly everyone who bends over the crib of a baby bursts into bubbling, musical tones to try to get the infant’s attention. This baby talk, or “motherese,” is widely considered to be a universal feature of human language, but now sci-entists report that a similar phenomenon might exist in other species—a fi nding that could help explain baby talk’s evolution.

Rhesus monkeys use special vocalizations called grunts and girneys when they are around infants, but most researchers had believed the monkeys were directing the sounds at the mothers holding the babies. Now University of Chicago biologists Dario Maestripieri and Jessica Whitham have shown in a careful observational study that the monkeys were aiming the soft, nasal sounds at the infants. The vocalizations, Maestripieri says, are probably intended to get the newborn’s attention and facilitate social interactions among group members—some of the same functions baby talk is thought to serve in people.

This monkey version of baby talk lends support to the popular theory that motherese helps humans build connections with their infants by attracting and holding the babies’ attention. Some researchers believe that the interest babies show in motherese could aid language development, and a few linguists take the idea a step further, suggesting that the extended vowels and exaggerated tones of motherese could teach infants basic grammar. Others contend, however, that the

melodic sounds may have a simpler purpose—to facilitate comprehension.

This hypothesis is supported by another new study, which showed that motherese can convey meaning between people who do not speak the same language. Cognitive psychologist Greg Bryant of the University of California, Los Angeles, found that the Shuar people of South America, who do not speak or understand English, were able to get the gist of North American mothers’

utterances 75 percent of the time when the women spoke as if they were addressing a newborn. This cross-cultural comprehension of motherese suggests that its basic characteristics appeared early in human history—and that it may have originated for the same socially benefi cial reasons that led our monkey relatives to develop their own form of baby talk. —Kat Leitzell

Monkeys, like humans, build connections

with their infants by

using special vocalizations.

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LEARNING

Shoot First, Ace Geometry LaterVideo gaming may eliminate the gender gap in spatial skillsPlaying an action-packed video game nearly wipes out sex differences in a basic spatial thinking task, research reveals. In a study of college students, men were better than women at rapidly switching their attention among stim-uli displayed on a computer screen, a common test of spatial ability. But after both sexes played the role of a World War II soldier in a video game for 10 hours over several weeks, women caught up to men on the spatial-attention task, as well as on an object-rotation test of more advanced spatial ability. Women’s gains persisted when the volunteers were retested an average of fi ve months later.

The study’s lead author, University of Toronto psychologist Ian Spence, speculates that the video game practice may have caused “massive overexercising” of the brain’s attentional system or even switched on previously inactive genes that underlie spatial cognition. Either way, he says, the results hold tantalizing potential for designing action-intensive video games that appeal to girls and women, perhaps eventually boosting women’s participation in fi elds such as mathematics and engineering, which demand good spatial ability. [For more about sex differences in spatial ability and scientifi c aptitude, see the article by Diane F. Halpern et al. on page 44.] —Siri Carpenter

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