Source: University College London

Summary: A recent study shows that, contrary to popular belief, human newborn’s brains aren’t substantially less developed than monkey species. It just appears that way since so much brain growth occurs after birth.

Humans have brains that are typically developed for similar primate species at birth. However, because human brains are so complex than other species, it is mistakenly believed that newborn humans are underdeveloped.

According to lead author Dr. Aida Gomez-Robles of UCL Anthropology, “This new work changes the overall understanding of 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.”

Measuring the difference between a species’ birth and adult brain sizes allows scientists to study how their brains evolve.

People appear less mature at birth than other monkey species because humans have smaller brains than other monkeys.

This new study, however, demonstrates that this metric is deceptive because human brain growth is broadly comparable to that of other primates, including chimpanzees, bonobos, gorillas, and orangutans, according to other assessments.

The study casts doubt on accepted theories about how the human brain develops over evolution.

Due to less physical control, it has been believed that humans are born with less developed brains than other animals.

In order for newborn’s heads to fit through their mothers’ birth canal, they had to further develop outside of the womb, which was assumed to be the outcome of an evolutionary compromise.

On the basis of this knowledge, scientists proposed that humans have more pliable brains in their early lives and are more susceptible to external stimuli as they mature, because humans emerged relatively underdeveloped.

It was believed that this early underdevelopment led to increased brain plasticity, which in turn promoted human intelligence.

The reason why human brains take longer to reach their maximum potential than those of other animals

It’s not because their brains are significantly underdeveloped at birth, researchers claim; it’s because their brains develop far more slowly.

Results make it less likely that humans’ superior brain plasticity is the result of being born less developed than other primates. The researchers noted that their findings do not discount the significance of brain plasticity in human evolution.

Scientists examined 140 distinct mammal species including primates, rodents, carnivores and related ancestors of hominins, to understand the human brain.

To comprehend how human brains evolved, researchers analysed the length of fatal gestation in current mammals. The proportion of newborn bodies and brains to those of adults, and the total size of newborn and adult brains

Researchers found that while the brain development of many animal species varies significantly at birth, monkeys’ brains are quite similar.

Both current monkeys and their hominin relatives do not have considerably lower developmental stages at birth than humans.

In the US, the National Institutes of Health and the National Science Foundation funded the study.