From Newsgroup: sci.anthropology.paleo
https://phys.org/news/2025-09-fast-brains-humans-marmosets.html
When a baby babbles and their parents respond,
these back-and-forth exchanges are more than
adorable-if-incoherent chatterrCothey help to
build a baby's emerging language skills.
But it turns out this learning strategy makes
humans an oddity within the animal kingdom.
Only a handful of other speciesrCoincluding a
few songbirds such as cowbirds and zebra
finchesrColearn to "talk" by noting their
parents' reactions to their initial coos and
gurgles.
How did humans become adept at learning
language this way? A new study across multiple
members of the primate family tree suggests the
answer may lie, in part, in newborn babies'
fast-growing brains.
Published August 19 in the journal Proceedings
of the National Academy of Sciences, the
findings come from research on a squirrel-size
monkey called the marmoset.
In the wild, marmosets use their high-pitched
calls to stay in touch when they're out of sight
of one another in the thick, dense forests of
northeastern Brazil.
Just over a decade ago, while studying marmoset
vocalizations, Princeton professor of
neuroscience and psychology Asif Ghazanfar and
colleagues noticed that baby marmosets go
through a babbling phase, just like humans do.
As newborn marmosets grow, their first
sputtering cries transform into the more
whistle-like calls of adults. The researchers
also found that baby marmosets who received more
frequent adult feedback during their babbling
bouts were quicker to catch on. They learned to
produce adult-like calls significantly faster
than the controls.
...
In the new study, led by Princeton Ph.D. student
Renata Biazzi, the researchers collected and
analyzed previously published data on the brain
development of four primate species including
humans, marmosets, chimpanzees and rhesus
macaques, from conception to adolescence.
The results suggest that, in early infancy, the
brains of humans and marmosets are growing faster
than those of other primates. Importantly, most
of that growth happens not in the confines of the
womb, as is the case for chimpanzees and macaques,
but right around the time they are born and first
experience the outside world.
In marmosets, as in humans, this also happens to
be an incredibly social time, Ghazanfar said.
That's because marmoset moms, like human mothers,
don't raise their offspring without help. Babies
interact with multiple caregivers who respond to
every cry.
...
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