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Brain Size And IQ: 8,000 Scans Test The Link

Brain Size And IQ: 8,000 Scans Test The Link post image

Scans of over 8,000 people were analysed by scientists searching for a link between IQ and brain size.

For 150 years scientists have suspected that a bigger brain means a higher IQ.

But the link may be much smaller than previously thought.

Now, a new study finds that having a larger brain only has a very small link to a higher IQ.

The results of brain scans from over 8,000 people were analysed by scientists at the University of Vienna and elsewhere.

Dr Jakob Pietschnig, who led the study, said:

“The presently observed association means that brain volume plays only a minor role in explaining IQ test performance in humans.

Although a certain association is observable, brain volume appears to be of only little practical relevance.

Rather, brain structure and integrity appear to be more important as a biological foundation of IQ, whilst brain size works as one of many compensatory mechanisms of cognitive functions.”

So, what makes the human brain superior is the connections not its size — relative or otherwise.

This is why, although women have smaller brains than men (on average), there is no difference in IQ between men and women (on average).

The study was published in the journal Neuroscience and Biobehavioral Reviews (Pietschnig et al., 2015).

About the author

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, 2003) and several ebooks:

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Network brain image from Shutterstock