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[♪ INTRO]
There’s always a scene in crime TV shows where a good guy
detective brings a suspect to the station for interrogation.
The detective isn’t getting anywhere until finally, he spots it.
The suspect looked to the right when they answered their last question,
a telltale sign that someone was lying.
We got them, case closed, roll the credits.
But in the real world, that detective may have
arrested a completely innocent person for just thinking.
When you answer a question, and you look right, or left, or any direction really,
that doesn’t mean you’re lying! Your eyes do that all the time regardless of the
question you’re answering.
And it makes sense. Looking at something or someone while answering a
question can make it harder to think, so you might look away from what’s in front
of you to ponder an answer.
But scientists have observed that we don’t look away just to avoid distractions;
even if you’re alone or have your eyes closed, they keep moving.
In fact, rapid, involuntary eye movements, called saccades,
continue for as long as you’re thinking, and why that happens is linked to what
you’re thinking about specifically.
For example, if you’re doing a lot of visual thinking, like a brain teaser,
remembering a picture, or moving an item in your head, your brain might treat that
as if you were actually looking at or moving that object.
What’s more impressive is that while you’re holding that mental picture,
your eyes will move in the exact same pattern as the
first time you looked at whatever you’re imagining!
And it’s not that you remember how your eyes
moved the first time you saw the object.
The same saccade pattern will still happen if what you’re imagining came from a
verbal description instead of actually seeing it.
By studying these eye movements, scientists can determine which strategies
people use during problem-solving and what stage they’re on.
For example, if you were to figure out if two images mirror each other,
you’ll need to imagine the shapes and rotate them
in your mind to picture them from different angles.
And the way you tend to move your eyes while doing this can
suggest that you typically break the shape down into
smaller chunks and then rotate each one individually.
But with visual thinking, it’s hard to sort out which eye movements are due to
visual processing, and which ones might be due to just, well, thinking.
Because our eyes don’t just move when we’re thinking about visual problems.
They move even more when we answer verbal-based questions like,
“do you remember what you wore yesterday?”
Researchers think that that’s because our eyes move when we’re searching our
long-term memory, which happens more often with verbal questions
because we need to remember things from different times,
and all that recalling involves eye movements.
In fact, there’s some evidence that your eyes move to different places when you’re
thinking about the past, present, or future.
So, in the same way that your eyes search through visual space, where each eye
position corresponds to a point in space, your eyes might be searching through
time, with each eye position corresponding to a different point on a timeline.
Although it’s still unclear whether eye movements are necessary for non-visual
thinking, or if they just happen at the same time.
Like, there’s some evidence that intentionally making large eye movements back
and forth might help memory recall, but most of the unconscious saccades we
make while thinking are really small.
Not to mention that intentionally suppressing eye movements doesn’t seem to
make a difference in memory recall.
So research on whether saccades actually serve a
function while thinking is mixed.
But some scientists think that these non-visual-related eye movements might be
an artifact of how our brain evolved. So the circuits used to search long-term
memory evolved from the ones used to search visual space.
That would mean those eye movements we make while thinking are vestigial, a
remnant of an earlier stage in the evolutionary process, and we don’t
technically need it to search our memory.
And while this phenomenon has been studied for more than 50 years,
it’s also been the fuel for some myths.
Like, remember that idea that you can be a human lie detector if you see
someone looking to the right? There’s pretty much no evidence to support that.
In fact, there’s not much evidence that the direction
our eyes move while thinking means anything at all.
So, unfortunately, those detectives are going to have
to do a little more work to figure out who the killer is.
But if they want to know what their suspect was thinking,
they can always call CS…eye.
Or you know, they can work on their logic skills with
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[♪ OUTRO]