I'm Dr Chris Street.
I'm a reader in cognitive psychology
and the University of Huddersfield.
I've always had an interest
in how people deceive others -
for example, if I were lying to you
right now, how would you know?
Would you look at my eyes?
At my body language?
Would you look me up online?
I'm Chris Street,
I'm a reader in psychology at
the University of Huddersfield.
If we want to detect deception
we need to stop looking for
those visual behaviours
that we think relate to deception,
like eyecontact or fidgeting.
Instead we need to
start thinking about
the pieces of information
we can find in the world
that match or mismatch with
the statement being offered.
If you want to be able
to accurately detect
somebody's lies or truths
what you need to do is, you need
to listen to what they're saying
and the way that they say it,
not how they're acting.
Think about when you are
talking to somebody,
you meet them for the first time, now
any good poker player will tell you
that it is very easy
to control your face.
Therefore facial cues
really aren't good cues
of whether or not somebody
is lying or telling the truth.
What you should be doing is
you should be listening
to what people say -
the verbal cues and
the way in which they say it -
the vocal cues.
A lie teller, because they are
trying to think very hard,
they will use probably the same
word over and over again
over a very short period of time.
There's some general research
that suggests
we are about 54% accurate when it
comes to detecting lies and truths
and as I always say, "If that's the
case, you might as well flip a coin -
you'll be just as accurate."
There are some people who think
they are lie detection wizards.
That they can read subtle
clues that we give off.
The research suggests
that this isn't the case,
that there aren't
lie detection experts.
Liars just don't give themselves away
in any obvious fashion.
There aren't good clues to deception,
we don't avoid eye contact,
we don't scratch our face when
we're lying or telling the truth.
These just aren't reliable
indicators and so, expert or not,
we have no good information
on which to make that decision.
We have this idea that
if somebody is lying to us
they can't keep our eye contact.
Now of course, liars know this
and what they will do is
they will keep your eye contact
ever so slightly longer than normal,
just enough to make you
feel uncomfortable.
Number two misconception tends to be
when people lie
they move about a lot,
they kind of get very nervous.
In fact the opposite is true. When
we lie, we have to think really hard.
So imagine you've got
a limited amount of energy,
you will channel all of that
energy into telling a lie
and as a consequence, you will
become ever so slightly stiller
than you normally are.
A third misconception
is the idea that
if we look up to the right
or we look up to the left,
it determines the type of lie
or truth that we're telling.
A recent piece of research has
in fact debunked the idea
that looking up that way
or looking up that way
is a good way to detect
deception, it's not.
My top tip for accurately determining
whether somebody is lying
or telling the truth
is using something that
we call the honest baseline
Now the honest baseline
is understanding
how people act and speak
when they're not stressed
and when they're being truthful.
So when we ask them a question,
now if we find a pretty even match
between the way they normally act
and the way that they're acting now,
we will be fairly happy that they're
probably telling us a truth.
If we find a mismatch,
it might indicate that there
is something going on here
that we need to follow up with
in a bit more detail.
ALIED theory, or the...
...argues that when we try to decide
if someone's lying
or telling the truth
what we're doing
is actually quite functional
and informed with our past experience
and with the information
available in the world.
For instance if I claim to have
gone to France last week
and I have a selfie of me in France
that's a great piece of information
that I was actually there.
But often we don't have that sort
of information, so what do we do?
ALIED theory claims that we,
rather than simply guess,
rely on our past experience of the
world to make an informed judgement.
People tend to be truth biased,
they tend to believe
people are telling the truth,
and that may be something
we want to get rid of.
The best thing to do is
just try to keep an open mind
and engage with the situation
in a sceptical manner.
I'm Dr Chris Street. I... Nope.
Do I have to say it
exactly how you've done it
or can I just say it as it comes out?
I'm Dr Chris Street.
I'm a reader in cognitive psychology
at the University of Huddersfield.
I'm like, moving my hands here,
you can't see.
Thanks for watching.
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