The evolution of the human brain lead to our brains being immature at birth 🧠
Of all the mammals, we humans have the least mature brain at birth. Early in their infancy other newborn mammals perform tasks far beyond the capabilities of human babies. A horse, for example, can run on its first day of life. Not for a year and a half or more can most humans muster the muscle strength, visual acuity, and neurological control skills—perception, balance, orientation in space, coordination—to perform that activity. In other words, the horse’s brain development at birth is at least a year and a half ahead of our own—probably even more, in horse years.
Why are we saddled with such a disadvantage in comparison to a horse? We can think of it as a compromise imposed by Nature. Our evolutionary predecessors were permitted to walk upright, which freed two other limbs to evolve into arms and hands capable of many delicate and complicated activities. Those advances in manual versatility and dexterity required a tremendous enlargement of the brain, especially of its frontal areas. Our frontal lobes, which coordinate the movement of our hands, are much larger even than those of our closest evolutionary relative, the chimpanzee.
As we became a two-legged species, the human pelvis had to narrow to accommodate our upright stance. At the end of the nine months of human gestation the head forms the largest diameter of the body, the part that is most likely to get stuck in our journey through the birth canal. If we had any further brain growth in the uterus then we couldn’t be born.
References
- Mate, Gabor. (2010). In the Realm of Hungry Ghosts Close Encounters with Addiction Chapter 17. Their Brains Never Had a Chance (p. 229). Berkeley, CA: North Atlantic Books.
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Type:🔴 Tags: Biology / Neuroscience / Developmental Neurology Status:☀️