CRITICAL THINKING - Cognitive Biases: Anchoring [HD]

In this video, the cognitive scientist Laurie Santos (Yale University) explains the phenomenon of anchoring. She shows how arbitrary information sometimes can sometimes act as an anchor that affects our judgments in unexpected ways.

(intro music)

My name is Laurie Santos.

I teach psychology at Yale
University, and today

I want to talk to you about anchoring.

This lecture is part of a
series on cognitive biases.

Let's do a math problem.
really quickly, and you've

gotta do it in your head

Ready?

First, multiply the following numbers:
eight times seven times six

times five times four times three times
two times one.

OK, that's it.

What's your guess?

A thousand?

Two thousand?

When the psychologists Danny Kahneman
and Amos Tversky tried this with

human subjects, subjects on average

guessed about two thousand
two hundred and fifty.

Seems like an OK guess.

But now, let's suppose I gave you
a different math problem.

What if I gave you this one?

Ready?

One times two times three times four

times five times six times
seven times eight.

What's your answer?

If you're like Kahneman and Tversky's

subjects, your answer might
be a bit different here.

For this question, their subjects
guessed a lot lower.

On average they said the answer
was about five hundred and twelve.

The first amazing thing
about these similar

mathematical estimates is that people get
the answers really, really wrong.

In fact, the real answer?

Well, for both, its forty thousand
three hundred and twenty.

People are off by an order of magnitude.

But the second, even more amazing
thing is that people give

different answers to the two problems,
even though they're just different ways

of asking exactly the same question.

Why do we give completely different answers,

when the same math problem
is presented differently?

The answer lies in how we make estimates.

When you have lots of time to do a math

problem, like eight times seven times six
times five times four times three times

two times one, you can multiply all of

the numbers together and get an exact product.

But when you have to do the problem

quickly, you don't really have time to finish.

So you start with the first numbers.

You multiply eight times
seven, and get fifty-six.

And then you've gotta
multiply that by six,

and, well, you're guessing the final
number's gotta be pretty big, bigger than

fifty-six, like maybe two thousand or so.

But when you do the second problem, you start

with one times two, and, well, that's only
two, and two times three's only six.

Your answer's gonna be pretty small,

maybe only like five hundred or so.

This process of guessing based on the first

number you see is what's
known as "anchoring."

The first number we think of

when we do our estimate is the anchor.

And once we have an anchor in our head,

well, we sort of adjust
as needed from there.

The problem is that our minds are biased
not to adjust as much as we need to.

The anchors are cognitively really strong.

In the first, problem you probably
started with fifty-six, and

then adjusted to an even
bigger number from there.

And in the second problem, you started
with six, and then adjusted from there.

The problem is that starting at different
points leads to different final guesses.

Like real anchors, our estimated anchors
kinda get us stuck in one spot.

We often fail to drag the anchor far
enough to get to a correct answer.

Kahneman and Tversky discovered that this

sort of anchoring bias happens all the time,

even for anchors that are totally arbitrary.

For example, they asked
people to spin a wheel with

numbers from one to a hundred,
and then asked them to estimate

what percentage of countries in
the United Nations are African.

People who spun a ten on
the wheel estimated that

the number was about twenty-five percent.

But people who spun a
sixty-five estimated that

the number was forty-five percent.

In another experiment, Dan Ariely
and his colleagues had people

write down the last two digits
of their social security number.

They were then asked whether they would

pay that amount in dollars
for a nice bottle of wine.

Ariely and colleagues found that people
in the highest quintile of social security

numbers would pay three to four times
as much for the exact same good.

Just setting up a larger anchor can make a

person who would pay eight
dollars for the bottle

of wine be willing to spend
twenty-seven dollars instead.

Sadly for us, sales people use
anchors against us all the time.

How many times have you noticed
a salesperson or an advertisement

anchoring you to a particular price, or

even to how much of a particular
product you should buy?

Whether it's buying a car, or a sweater,

or even renting a hotel room, our
intuitions about what prices

are reasonable to pay often come
from some arbitrary anchor.

So, the next time you're given an
anchor, take a minute to think.

Remember what happens when you

drop your anger too high, and then

consider thinking of a
very different number.

It might affect your final estimate
more than you expect.