It has been claimed previously that women speak about 20,000 words a day – some 13,000 more than the average man.
But now scientists have found the key to explaining why women are the more talkative sex.
A published study suggests that higher levels of the protein are found in the female brain.
Both male and female pups emitted hundreds of cries, but the males called out twice as often. As a result, when the pups were put back in the same cage as their mother, she fussed over her sons first.
The researchers then ramped up its production in the brains of female pups and reduced it in males. This led to the female rats crying out more often and their mothers showing more interest to them.
The males in contrast, became less ‘talkative’, the Journal of Neuroscience reports. Next, the University of Maryland researchers tested samples from ten boys and girls aged between three and five.
This showed the girls to have 30 per cent more of the Foxp2 protein than the boys, in a brain area key to language in humans.
Researcher Margaret McCarthy said: ‘Based on our observations, we postulate 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.’
Studies have shown that the female love of chit-chat begins at a young age. Girls learn to speak earlier and more quickly than boys. They produce their first words and sentences earlier, have larger vocabularies and use a greater variety of sentence types than boys of the same age.
However, Simon Fisher, one of the Oxford team who first pinpointed the protein, cautioned against drawing big conclusions from a study of such a small number of children.