How Smart People’s Brains Work: They Are Different

Smart people’s brains are not just bigger, they are also different. Here’s how.

Smart people’s brains are not just bigger, they are also different. Here’s how.

People with bigger heads are, on average, more intelligent, research confirms.

Bigger heads contain bigger brains, which have more neurons (brain cells), which make people smarter.

However, the latest neuroscience research suggests there’s a twist.

When you ‘listen’ electrically to the brain running, the more intelligent ones make less ‘noise’.

It’s like a larger, more powerful engine somehow running quieter.

Smart people’s brain are different

It turns out that on top of having larger brains, more intelligent people have fewer connections between neurons in the cerebral cortex, research finds.

The reason is that the brains of intelligent people are more efficient — this is known to psychologists as the ‘neural efficiency hypothesis of intelligence’.

The conclusion comes from a neuroimaging study that looked at the brain’s microstructure.

Analysis of the brains of 259 people measured the number of dendrites in their brains.

Dendrites are extensions of brain cells that reach out towards other brain cells, enabling them to communicate with each other.

IQ tests showed that people with fewer dendrites were more intelligent.

Smart people’s brain are more efficient

It is more than just size that matters, it is how efficiently your brain cells communicate.

With fewer dendritic connections there is less ‘noise’ in the brain and the signal is purer.

Fewer dendrites also consume less energy — hence, a more efficient brain.

Here is the author’s schematic depiction (from Genç et al., 2018):

Dr Erhan Genç, who led the study, said:

“The assumption has been that larger brains contain more neurons and, consequently, possess more computational power.

However, other studies had shown that — despite their comparatively high number of neurons — the brains of intelligent people demonstrated less neuronal activity during an IQ test than the brains of less intelligent individuals.

Intelligent brains possess lean, yet efficient neuronal connections.

Thus, they boast high mental performance at low neuronal activity.”

The study was published in the journal Nature Communications (Genç et al., 2018).


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Hello, and welcome to PsyBlog. Thanks for dropping by.

This site is all about scientific research into how the mind works.

It’s mostly written by psychologist and author, Dr Jeremy Dean.

I try to dig up fascinating studies that tell us something about what it means to be human.

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Author: Jeremy Dean

Psychologist, Jeremy Dean, PhD is the founder and author of PsyBlog. He holds a doctorate in psychology from University College London and two other advanced degrees in psychology. He has been writing about scientific research on PsyBlog since 2004. He is also the author of the book "Making Habits, Breaking Habits" (Da Capo, 2013) and several ebooks.