This is a man named Bob Rosenthal, and early
in his career as a research psychologist,
he did something very devious.
Late one night, Bob secretly crept into his
lab, and he hung signs on all of the rat cages.
Some of the signs said that the rat in the
cage was incredibly smart, and some of the
signs said that the rat in the cage was incredibly
dumb, even though
neither of these things was true.
So then Bob brings this group of experimenters
into his lab and says, "For the next week, some
of you are going to get these very smart rats,
and some these very dumb rats, and your job
is to run your rat through a maze and record
how well it does."
So what did they find?
It was not even close.
The smart rats did almost twice as well as
the dumb rats.
Even though they weren't...?
Even though the smart rats were not smart
and the stupid rats were not stupid.
They were just all the same kind of average
North Dakotan rat.
That almost to me sounds like the stuff of
science fiction, like telekinesis.
Yeah!
No one really believed him at first.
"I was having trouble publishing any of this."
But what Bob eventually figured out was that
the expectations that the experimenters had
in their head actually translated into a whole
set of tiny behavior changes.
"Handling rats and handling them more gently
can actually increase the performance of rats."
This kind of dynamic happens in people, too.
"You may be standing farther away from someone
you have lower expectations for, you may not
be making as much eye contact, and it's not
something you can put your finger on."
That's Carol Dweck, a psychologist at Stanford.
She was one of several researchers who
explained all kinds of surprising things that
expectations can influence.
Like, teacher expectations can raise or lower
a student's IQ score.
A mother's expectations can affect the drinking
behavior of her middle-schooler.
Military trainers' expecations can literally
make a soldier faster or slower.
Think about that, as you go through the world,
expectations of other people are constantly
acting on you, literally making you stronger
or weaker, smarter or dumber.
Faster or slower?
Yeah!
So my question was, "How far does this go?"
So Carol, for example, if I expect that if
somebody jumps off a building they will be
able to fly, that's not gonna work out so well, right?
"Right."
So what does science know about where we should
draw the line?
"That line is moving as we come to understand
things that are possible, and mechanisms through
which a belief affects an outcome, or one
person affects another person.
That line can move."
