American researchers found females are the more talkative sex because of a special“language protein” in the brain. The study, compiled by neuroscientists and psychologist from the University of Maryland, concluded that women talked more because they had more of the Foxp2 protein. Their findings come after it was previously claimed that ladies speak about 20 000 words a day — over 13 000 more than men. “This Study is one of the first to report a sex difference in the expression of a language-associated protein in humans or animals,” said Prof. Margaret McCarthy, who led the study. “The findings raise the possibility that sex differences in brain and behavior are more pervasive( 普遍的 ) and established earlier than previously appreciated.” The research, published in the Journal of Neuroscience, found that higher levels were found among humans that were women but in rats they were males. In the experiment, the researchers attempted to determine what might make male rats more vocal( 有声的 ) than their female friends. They separated four-day-old rats from their mothers and then counted the number of times they cried out over five minutes. While both sexes emitted hundreds of cries, the males called out twice as often, they found. According to tests compiled on the parts of the brain known to be involved in vocal calls, the male pups( 幼崽 ) have up to twice as much Foxp2 protein as the females. The researchers then increased the production in the brains of female pups and reduced it in males. This led to the female rats crying out more often. In contrast, males became less “talkative”. There searchers then tested samples from ten children, aged between three and five, which showed that females had up to a 30 percent more of the Foxp2 protein than males, in a brain area key to language in humans. “Based on our observations, the assumption of higher levels of Foxp2 in girls and higher levels of Foxp2 in male rats is an indication that Foxp2 protein levels are associated with the more communicative sex,” said Prof. McCarthy. “Our results implicate Foxp2 as a component of the neurobiological basis of sex differences in vocal communication in mammals.” Q: The study conducted by American researchers is mainly to reveal ________.