Are you ready for a quick test? 3… 2… 1…
Say the color not the word
Put your hand on your head.
Which hand did you use?
Look at this word and close one eye.
Which eye is still open?
Questions like these are purported to show how our
brains work while also revealing our key mental strengths and weaknesses.
It asks ‘Are you right-brained or left-brained?’
According to these sorts of personality tests there are
two dispositions that make up a person’s identity.
Those of us with more dominant right-sides are said to be the spontaneous, intuitive,
creative ones, while those of us with left-sided dominance are labeled as
logical and analytical sorts who love getting stuck into the finer details.
But can we all be reduced to two archetypes? Is it really a world of artists vs scientists?
I’m Stu, this is Debunked and we’re here to sort the truths from the myths
and the facts from the misconceptions.
This video is sponsored by BackBlaze.
It’s actually quite easy to distinguish a left side and a right side of the brain just
by looking at it and, here’s the thing, there is a difference between the two hemispheres.
On the whole, the right side of your brain
controls the left side of your body and vice versa.
This might seem counter intuitive, and the reason for this criss-crossing or decussation of the
nervous system is still debated by evolutionary biologists but it is common among vertebrates.
One theory put forward, called the somatic twist model, argues that this came about with the
appearance of the earliest vertebrates and that our bodies essentially went on a 180-degree twist
relative to the brain - or to put it another way, our heads are on backwards.
A different model suggests that an evolutionary ancestor was born with
a head at 90 degrees to the body and that their bodies consequently evolved
90 degrees in the opposite direction, again essentially leaving the head on backwards.
Regardless of how we got here,
this right-side/left-side split goes beyond simply controlling the two sides of the body,
as different areas of the brain are responsible for other key elements of cognitive function.
“IT'S ABSOLUTELY TRUE THAT SOME BRAIN FUNCTIONS OCCUR IN ONE OR THE OTHER SIDE OF THE BRAIN,
LANGUAGE TENDS TO BE ON THE LEFT, ATTENTION MORE ON THE RIGHT.”
This division of labor is made abundantly clear when damage occurs to the brain.
Take, for example, the impact of a stroke on physical ability,
mental function and behavior. A stroke causing damage in one
side of the brain can result in paralysis on the opposite side of the body, as expected.
Other effects are more specific to the hemisphere in which the damage occurs.
Right-side, it can cause vision problems and induce impulsive, quick behavior.
Whereas on the left side, a stroke can result in speech or language
problems and bring about a more cautious personality.
That injuries to a particular side of the brain can lead to
the loss of specific abilities has been known since the 19th century,
and it’s likely the origins of the left-side vs right-side debate originated here…
…but it was the work of scientists in the 1960s that really shone a
light on how the two sides of the brain differed.
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So far we’ve spoken of the brain in terms of two hemispheres,
almost as if it wasn’t a single organ,
but it’s crucial to remember that those two hemispheres are connected through something called
the corpus callosum - a band of neural fibers that lets the two sides communicate with each other.
Back in the 1960s though, the corpus callosum was sometimes
deliberately severed in people suffering from a severe form of epilepsy, creating what is
known as ’split brain’ patients. Since the two sides of the brain could no longer interact,
it was now possible to observe how the two sides responded to various stimuli and
…this is exactly what neuropsychologist Roger Sperry did.
His work, and that of his colleagues, which won the Nobel Prize in 1981,
established details like the right side of the brain handling music and space perceptions - if
you’re giving out directions or making a map, yep, that’s the right side doing its job.
The left side of the brain specialized in taking care of analytical and verbal tasks - speech,
for example, was much stronger on the left side,
with the right only being able to produce basic words and phrases.
However, split-brain experiments also showed that
the right hemisphere contributed to language by adding emotional context,
meaning that without your right hemisphere you could read the word
‘dog’ but not be able to imagine what one is.
What this latter example shows is that the right side and left side of the brain
and the abilities normally associated with each
are not mutually exclusive.
Both sides of the brain work together when it comes to language
and this cooperation stretches to other areas too.
“THIS KIND OF PATTERN, IN WHICH BOTH HEMISPHERES OF THE BRAIN MAKE CRITICAL CONTRIBUTIONS, HOLDS
FOR MOST TYPES OF COGNITIVE SKILLS. IT TAKES TWO HEMISPHERES TO BE LOGICAL – OR TO BE CREATIVE.” -
Even those labels can be problematic. Take Maths
(or Math, if you prefer) - on the face of it, a ‘logical’ rather than a ‘creative’ skill
and a job for your lab-coat-wearing left-brain rather than your beret-wearing-boho-chic
right-brain but that’s not how it plays out in reality.
The right hemisphere contributes in areas like estimating numbers of objects,
while the left hemisphere is great when it comes to counting and recalling multiplication tables,
since these rely on memorized verbal info. So that’s both sides being logical.
"Without a doubt the popular left and right division of the brain is an over-simplification.
For example, research is showing that musical, artistic and intuitive thinking
can't be thought of as strictly lateralized, or exclusively of the right hemisphere "
Okay, so we’ve established that our brains are divided into two
hemispheres which handle specific abilities,
but if those hemispheres work together across so-called logical and creative
things is it even possible to be left-brain or right-brain dominant?
Well, no. It isn’t. It turns out those online ‘brain’ tests
and the personalities attached to them are nothing but a myth.
In 2013, neuroscientists at the University of Utah published the results of a study
that involved scanning the brains of over 1,000 people.
The study did uncover patterns and reasons for brain connections to be
particularly left or right sided, but they found no evidence of the
brain network being stronger in either hemisphere amongst any of the subjects.
In other words, there is no such thing as left- or right-sided dominance.
“The pop culture idea (creative vs. logical traits) has no support in the
neuroscience community and flies in the face of decades of research about brain organization,
the functional roles of the two brain hemispheres and evidence
from patients with lesions in one or the other hemisphere in the brain"
The notion of hemisphere dominance doesn’t stack up from an efficiency point of view either -
there wouldn’t be much point in having, for example, a right hemisphere sitting
there twiddling its neurons while your left brain was in overdrive doing most things.
Instead, having both sides work semi-independently, utilizing different
approaches and perspectives, is a far more complimentary strategy for solving problems.
So how come this idea of our personalities
being linked to a dominant side of the brain became so ubiquitous?
Well, it seems like the Nobel-prize winning research on ‘split-brain’
patients and the differences between the hemispheres was picked up by pop
psychologists as an easy way to explain why we act the way we do.
Before the internet, the right vs left brain debate was popularized in self-improvement books
and therapies that promised to unlock the secrets of your weak hemisphere
or capitalize on your strong side.
It’s not out of the realms of possibility that you’ve even been asked whether you’re
right- or left-brained on a job application.
Another area where the left/right brain debate has seeped into popular culture is in the
notion that you can tell if someone is lying by looking at the direction of their eye movement.
Apparently, a right-handed person looking to their right
is stimulating activity in the right side of their brain - the allegedly
creative half - so they must therefore be lying or making something up.
Aside from the substantial amount of evidence that the brain doesn’t have this demarcation
(‘dee-mark-ay-shon’) between the hemispheres, the lying thing has been disproven in dedicated tests.
The research utilized both lab experiments where people were asked to lie or tell the
truth as well as use of archive footage of interviews in missing persons cases,
where some of the people on camera were later found guilty of involvement in the disappearance.
In either scenario, those lying did not look to the right any more than they did the left.
The idea that lying and eye movement are in any way connected is,
in the words of the study’s lead author, Richard Wiseman ‘madness’.
“YOU MIGHT AS WELL JUST TOSS A COIN, AND IF IT COMES UP HEADS, YOU’RE GOING UP AGAINST A LIAR.”
On a more basic level, people want to believe in these left-side/right-side personality tests.
It’s an actual psychological phenomenon called the Barnum Effect, which means we often take
generic statements about our personalities that could apply to just about anyone
and interpret them as deep and meaningful to us. We’re predisposed to buy into this debate.
Now I’m not saying you shouldn’t enjoy dabbling in an online personality test or two,
but remember that being told you’re left or right-brained is about as factual as having
a palm reader tell you your future or convicting someone on a coin toss.
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