Human brains substantially vary in size and we’re talking adults, not necessarily children. Usually, men’s brains are bigger in size than women’s brains. Does this mean men are generally smarter than women? Any feminist and man in his right mind would say this is outrageous and stay chill, it is. Still, the question arises: why do brains vary in size from one adult to another? Does brain size correlate to intelligence? Does it influence a person’s ability to think and make logical assumptions? Usually, in these circumstances, you would think the bigger, the better, but is it really so?
Brain size and intelligence: Does it correlate?
No matter how funny and strange it might sound, we humans like to measure things a lot, and, ultimately, measure ourselves against the others: who has the biggest house, the most expensive car, more expensive clothes, who is the tallest and richest, etc. So, size does matter, no matter what the politically correct supporters might claim. But what about our brains? There has been a broad belief of the 19th century which continues to this day, in some cases, that the wider and higher the forehead, the smarter the person. A wider forehead means, by extrapolation, a bigger brain. The idea is that we cannot really measure the size of a nervous system and correlate it to the mental powers of the owner. Unfortunately, we don’t have a solid explanation of how intelligent behavior comes about.
The human brain in numbers
The human brain keeps growing until the age of 30-40. A study conducted on 46 mainly European adults found that the average male brain size was of 1,274 cubic centimeters, while the average female brain size was just 1,131 cubic centimeters. The variability is considerable, though, with people having brain volumes of 1,053 to 1,499 cubic centimeters. Russian novelist Ivan Turgenev’s brain was removed after death and they found out it weighed 2,021 grams, while French novelist Anatole France’s brain was barely 1,017 grams. Postmortem measures, though, are not as relevant as the data obtained from living healthy brains.
Does a bigger brain make you smarter?
This is a controversial question because the relation between brain size and intelligence is not well-defined. Us, humans, like to think ourselves as the kings of the world, way smarter than any animal and that would also make us the mammals with the biggest brains, but it is not so. Elephants or whales’ brains are huge compared to humans’. Actually, a man’s body to brain ratio resembles that of a mouse. Still not good enough, right? So, besides humans trying to compare brain mass of humans to that of animals, what about comparing brain mass of humans to that of other humans? Some claim there is a correlation.
With the aid of magnetic resonance imaging (MRI) scientists have been able to measure living brain sizes and compare them with the IQ. A study from 10 years ago concluded that the correlation between IQ and brain volume was consistent within the range of 0.3-0.4. Recently, a study conducted on 20,000 human subjects concluded that there is an “IQ” gene which accounts for increased intracranial volume as well as big IQ.
Still, neither of these studies is too convincing. Albert Einstein, the man of the 20th century had an average-sized brain. Did it stop him? Not really. The thing is we’ve only scratched the surface with the question here because the problem is deeper than it seems. We, humans, are still in great difficulty when it comes to defining intelligence. Does intelligence only mean the score on the IQ test? Does brain power only mean a bigger brain? Currently, there is a new series of studies going on trying to unravel the complexity of cellular and molecular organization of synapses and how it could influence a brain’s computational capacity.
So, does brain size correlate to intelligence? There is no clear yes or no as we speak.