Brain growth links human and marmoset speech learning
Marmosets have a similar 'babbling' phase to human babies.
A new study has explored the remarkable similarities between how humans and marmosets each learn to communicate.
Using a new mathematical model, researchers from Princeton University have suggested that rapid brain growth could link the two distantly-related species’ learning patterns.
The similarity was first identified over a decade ago, when researchers noticed that baby marmosets went through a similar ‘babbling’ phase to human babies. Newborn marmosets learned more quickly when they had adult feedback to their babbling, transforming their sputtering cries to whistle-like adult calls.
This speech is vital for marmoset survival, as high-pitched calls help them communicate through the thick dense forests of northeastern Brazil.
However the last common ancestor between humans and marmosets was over 40 million years ago, raising questions of why these two species are linked.
To explore this phenomenon, a new study has compared the brain development of four primate species from conception to adolescence. Researchers analysed previously published data on humans, marmosets, chimpanzees and rhesus macaques.
The analysis suggests that the brains of humans and marmosets grow faster than those other primates.
Much of this growth happens when humans and marmosets are born, and are first experiencing the outside world. However, for chimpanzees and macaques, most of this growth happens within the confines of the womb.
The early ‘babbling’ stage, coupled with this rapid growth, could be key for the development for their vocal skills.
Asif Ghazanfar, professor of neuroscience and psychology, said: “They are a handful,”
He added that, because their brains were still developing, “the social environment an infant is born into has a tremendous influence”.
In future studies, the team will investigate marmoset ‘baby talk’ . They will explore whether there are specific sounds that an adult marmoset will make when interacting with infants.
It is hoped that marmosets, now found to be the only other primates whose infants use feedback to learn new sounds, to discover how cooing and babbling becomes more sophisticated speech.
The full study can be found in the journal Proceedings of the National Academy of the Sciences.
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