Friday, 29 August 2014

Brain myths debunked

The recently released ‘Lucy’ movie starring Scarlett Johansson has so far managed to take in $217 million, and earned the title of third highest-grossing opening ever for a female-lead action film. However, the entire plot line of the movie is based on a myth that pops up regularly in the media, and is even used in advertisements despite being an entirely false claim - it is the myth that we only use 10% of our brains.

The widespread conviction of this fable inspired me to debunk 3 of the most common myths believed about the brain - the 10% rule, whether we are left or right brained, and that size is a measure of intelligence.

1. We only use 10% of our brains:

A survey (pretty worryingly) showed that in 2012 that 48% of schoolteachers in Britain thought this myth to be true, demonstrating how widespread the belief is.

In the media, the myth is also a common theme, with the 2011 film ‘Limitless’ basing its plot around the same idea, in which Bradley Cooper was able access the rest of his brain after use of a drug. The 1996 movie ‘Phenomenon’ was also based on a man developing super-intelligence after a freak accident that allowed him to access his 'full brain potential'.

Films such as 'Lucy' depict the 10% myth as truth
The idea has also been attributed to Albert Einstein, with some hypothesising that his intelligence was due to being able to access more than the ‘normal’ 10%!

In reality, modern brain scanning technologies show that we do use 100% of our brain (even during sleep!), and over the course of a normal day every single area of the brain gets a workout. However, the reason this myth may have come about is because it is true that you don’t use all areas of your brain all the time - specific areas are more active during different activities. For example, when you are walking areas of the brain associated with movement are activated, as opposed to the areas associated with speech.

The fact that we don’t just use 10% can be shown through the devastating impact an injury on a small area of the brain can have on cognition and function. It also follows that if we did only use 10%, there would be a huge selection pressure (in terms of evolution), to select for those born with smaller heads. During childbirth, it is notoriously more difficult and dangerous to give birth to children with slightly larger skulls. Therefore it follows that if the tissue in our brains was majority waste, over time children that survived would be born with smaller brains – with less waste tissue around the functional 10%, and therefore a smaller head.

Not quite the case..!
However, despite the completely false plot I’m still extremely tempted to watch 'Lucy'!

2. You are either left or right-brained:

This myth seems to be even more widely believed than the first, even though it is also completely untrue!

Allegedly, if you are more analytical and logical you are more left-brained, but if you are more creative and intuitive you are more right-brained. In reality, this is not the case. It is true that you use different sides of your brain for different cognitive functions, such as the left side for language and the right side for reading emotion. However, the two sides work together to produce one result.

Although widely believed to be true, this analogy of the brain is completely false!
For example, if someone is speaking to you: You need the left side of your brain to pick out sounds that represent words and work out the syntax, but you need the right side of the brain in order to work out the emotional features of the language – such as the rhythms and tone of voice. The areas associated with these skills happen to be located on opposite sides of the brain.

Supposedly, this myth first started in the 1800s when doctors saw that injuries to a specific side of the brain resulted in a loss of certain abilities. However, modern brain scanning techniques show that there is no lateralisation (or dominance) of either side of the brain – you need both sides to work together.

3. Bigger is better:

Supposedly, the bigger your brain the more intelligent you are. However, this is also entirely false. Whilst it is true between humans that the amount of brain cells (but only a specific type of brain cells..) you have does factor in with your intelligence, the actual size of your brain is not a determining factor of how clever you are. 
Despite popular opinion, a larger brain doesn't make you smarter
This is demonstrated by the fact that a sperm whale’s brain is 6 times larger than a humans – whilst these animals are undeniably intelligent, their cognitive skills are considerably lower than humans!


Hopefully this post debunked a few of the most commonly believed myths about the brain for you! What are your thoughts on these? 

Is the belief in these myths harmless - do most people realise these claims are not meant to be taken seriously? 

Personally, I don't think there's any danger in people believing in these claims - the only danger is when people such as the 48% of schoolteachers that believe in the 10% rule are in the position to teach other people that these claims are true. 

What are your thoughts? Comment below and let me know!


  1. I definately thought number one was a fact! This is a really interesting blog post!


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  2. These myths always make me very grumpy! I'm constantly correcting people ;)

  3. I can't tell you how annoying I find the 10% myth! I don't know why people think that when I'm sure the majority of us have seen an MRI scan...

  4. That 10% thing really bugged me when I saw the Lucy trailer as I knew it wasn't true!