Is a bigger brain a smarter brain? Not necessarily

Is bigger better? Those engaged in the field of nanotechnology certainly don’t think so. Jockeys would disagree too. What about when it comes to brains? We readily use phrases like, “She has an enormous brain”, to indicate that someone is really intelligent but is a bigger brain a smarter brain? That was the question that researchers sought to answer in a new study.

The study involved 8,000 subjects and the researchers looked to see if there was a correlation between brain volume and performance on IQ tests. They found that there was only a very weak connection between brain size and IQ and they concluded that brain volume plays only a very minor role in predicting IQ test performance in humans. Rather than brain volume they say it is brain structure that more accurately predicts IQ but honestly, that isn’t really a surprise.

We readily use phrases like, "She has an enormous brain", to indicate that someone is really intelligent but is a bigger brain a smarter brain?

If absolute brain size were the determinant of intelligence then the sperm whale would be the Mensa graduate of the planet as it has the largest central nervous system. However, if you adjust to allow for body mass then the winner in terms of brain volume compared to body size is the shrew. Since relatively few treatises on the laws of thermodynamics or soul-searing novels have been attributed to shrews, it seems likely that brain volume alone does not determine the intelligence of a species.

Within humans we know that men have larger brains than women but of course, there is no difference in IQs between the sexes (opinions either way notwithstanding). Additionally people with megalencepthaly (a growth development disorder in which the brain is abnormally large) usually show lower than average IQ scores.

So it does seem that brain structure is more important than brain size in determining IQ which also means that if you do have a high IQ, you don’t have to be a big-head about it.