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[♩INTRO]
In order to deal with all the information the world throws at us,
human brains have developed cognitive ‘shortcuts’.
Usually, these shortcuts are helpful, and you’re totally unaware of them.
But sometimes, they can slow you down, or even be your downfall.
Today on SciShow, find out how your brain can betray you.
One of the most famous and well-studied examples of how our
brains’ automatic processing can trip us up is the Stroop task.
Its name comes from American psychologist J.R. Stroop,
who designed the test way back in the nineteen thirties.
And the set up is—or seems—really simple.
You’re presented with a series of words and asked either to name the color
of the ink the word is written in or simply read out the word.
Easy enough, right?
Sometimes, though, the ink is the same color as the word
like, red ink for the word red.
This is considered a congruent trial.
Other times, it isn’t—like, the word red written in green.
Those are incongruent trials.
And then there are neutral trials, where the word and ink color are unrelated
like the word dog is, you know....it’s not dog colored, I guess.
Stroop found that even when participants were instructed to ignore
that was written and just focus on the color of the ink,
it took them longer to answer during incongruent trials.
Sometimes, they even read the word by mistake!
That’s because reading words in a language you’re fluent in
is an automatic process
whether you like it or not, that information gets into your brain.
So when the info you get from reading the word is different from the color of the ink,
these two conflicting pieces of information end up fighting it out in your brain.
This is called interference because one cognitive process is slowing down another.
And this effect is so strong that some say US intelligence services
used the Stroop task to spot Russian agents during the Cold War.
The idea was that these agents were pretending to be Americans,
when really, they were from Russia and their first language was Russian.
So, the suspected spies were given the Stroop task in Russian.
People who don’t speak Russian should be able to rattle off the colors of the
words with ease, as they won’t be tripped up by the color-word mismatches.
So, if the suspected spy was slow to answer or got tripped up by words
written in Russian, the jig was up.
Of course, this would only have worked for spies that weren’t
supposed to know Russian.
Bilingual people get Strooped in both languages they speak.
So it’s probably not all that useful for detecting spies,
unless you’re talking, like, the deep undercover types.
The real question, though, is why this happens at all.
You see, Stroop quickly realized interference wasn’t the only thing happening.
There’s also facilitation—when one cognitive process helps another process along.
That occurs when multiple pieces of information complement each other
or work together—like when we read the word red in red ink.
And understanding how and why things interfere with or facilitate one another
could explain a lot about how our brains handle information.
We have a general sense of what’s happening
which is to say, we know the key parts of the brain involved.
While Stroop didn’t have access to neuroimaging in his time,
we now know that the Stroop effect involves an interplay between a few key areas:
the prefrontal cortex or PFC, the anterior cingulate cortex or ACC,
and the ventral tegmental area or VTA.
If you’ve seen our video about multitasking,
you already know that this network is responsible for executive control functions:
processes like working memory, planning, attention, and problem-solving.
With regards to the Stroop test,
the prefrontal cortex is thought to be responsible for goal representation
basically, what the rules of the current task are, like saying the word or saying the color.
Meanwhile, the ACC seems to be involved in error detection.
You see, studies have found ACC activity is higher during incongruent trials
as compared to congruent or neutral trials.
That suggests that the ACC is essentially flagging
when you’re most likely to make a mistake
and is probably responsible for your hesitation in answering.
Then, if we get it right,
the VTA provides a reward in the form of good old dopamine.
But brain activity in certain areas doesn’t really tell us as much as you’d think
about how the information is being processed.
There are a number of different models that aim to explain that,
none of which are perfect.
For example, there’s the Parallel Distributed Processing model,
which became popular in the late nineteen seventies to early nineteen eighties.
It imagines the brain much like a computer network, with different cognitive processes,
like word reading and color identification, occurring in parallel.
The path with the strongest activation is the one that ends up prevailing
and that’s naturally reading, because we spend so much time
learning how to do it and doing it, while we don’t tend to spend
as much of our lives pointing out the colors of things.
Other models posit that it’s not the strength of a given pathway,
but rather the speed at which a process occurs
and that we read faster than we ID color, basically.
And still others argue that word-reading simply doesn’t take the same
amount of focused attention as color-naming.
But none of these seem to line up with perfectly with what’s happening in the brain.
That’s why more recent methods for understanding the Stroop effect
include developing artificial networks to mimic what’s going on.
Basically, researchers are trying to write a computer program that responds to
the Stroop task in the same way humans do,
which could help connect the neuroanatomy and the proposed models.
Because one thing we know for sure is that all this is hardwired into your brain.
You can’t see the word green written in red and just totally ignore the word itself.
But… you might be able to hack these processes a bit.
You see, different people experience different degrees of this effect.
People who struggle with impulse control in general are more susceptible
to the Stroop effect than others, for example.
And there are definitely things that will make you worse, like intoxication.
News alert: being drunk makes you bad at a lot of things, especially impulse control.
There are ways to get better at the Stroop task, too.
Practice does improve performance, for example,
so you might be able to get a little bit faster.
But you’ll probably never be perfect… unless you undergo hypnosis, apparently.
You see, one 2002 study found that when put under hypnosis,
some people could master the Stroop task by becoming convinced
that the totally real and normal English words they were presented, were gibberish.
Which, along with being pretty spooky, provides evidence
that at least some automatic processes, like reading, can be overcome.
There’s just a lot we still don’t understand about how and why
our brains do the things they do every day.
And that’s why researchers are still using this super old test
because even after almost a century,
it’s still revealing the fundamentals of how our brains work.
And you can see how you do with the Stroop task, because it’s one of the
experiments in our Universe Unboxed Sensory Science kit!
Universe Unboxed is SciShow’s very own line of science experiment kits
for kids elementary school-aged and older.
They’re packed with all sorts of fun experiments which teach specific science concepts.
Each also has a video demonstration, starring me, so you can see how it’s done
and guess what happened before you learn the science behind them.
And in the Sensory Science kit, there’s a Stroop task that you can do right at home,
since it teaches us a lot about how our brains process visual information.
You can even see how I did by watching the accompanying video!
Hint: not great.
In addition to explaining the experiments, we also explain how scientists actually
use the scientific concepts you’re learning in the real world.
So you’re not only learning how science works, you’re learning why it matters,
just like you do when you watch SciShow episodes like this one.
To buy one of these kits for yourself or your favorite kid,
or to find them in a store near you, check out UniverseUnboxed.com.
[♩OUTRO]