Brains of newborns aren't underdeveloped compared to other primates

 Contrary to current understanding, the brains of human newborns aren't significantly less developed compared to other primate species, but appear so because so much brain development happens after birth, finds a new study led by UCL researchers.

The study, published in Nature Ecology & Evolution, found that humans are born with brains at a development level that's typical for similar primate species, but the human brains grow so much larger and more complex than other species after birth, it gives the false impression that human newborns are underdeveloped, or "altricial."

Lead author Dr Aida Gomez-Robles (UCL Anthropology) said: "This new work changes the overall understanding around the evolution of human brain development. Humans seem so much more helpless when they're young compared to other primates not because their brains are comparatively underdeveloped but because they still have much further to go."

One way that scientists compare the brain development of different species is by measuring the size of their brains as newborns to their brain size as adults.

Humans are born with a relatively smaller percentage of their adult brain size, compared to other primates, making it seem they're born less developed.

However, this new research shows that this measure is misleading as other measurements of human brain development show humans are largely in line with other species of primates such as chimpanzees, bonobos, gorillas and orangutans.

The research challenges a prevailing understanding of evolutionary human brain development.

Up to now, because of their helplessness and poor muscle control, it's long been believed that humans are born with comparatively less developed brains than other primates.

This was thought to be the result of an evolutionary compromise so babies' heads could fit through their mother's birth canal, which would require them to further develop outside of the womb.

Based on this understanding, scientists suggested that because humans emerged comparatively underdeveloped, their brains are more malleable in the earliest period of life and more easily affected by environmental stimuli as they grow.

sources-science daily