two-lecture sequence on social psychology on how we think about

ourselves, how we think about other people,

how we think about other groups of people.

We've talked a lot about the capacities of the human mind and

some of these capacities involve adapting and dealing with the

material world. So, we have to choose foods,

we have to navigate around the world, we have to recognize

objects, we have to be able to

understand physical interactions.

But probably the most interesting aspect of our

evolved minds is our capacity to understand and deal with other

people. We are intensely interested in

how other people work. The story that was a dominant

news story in 2005 was this. And some of you--this--for

those of you who aren't seeing the screen, is the separation of

Jennifer Aniston and Brad Pitt. I remember where I was when I

first heard about this. [laughter]

And it's an interesting sight. Just remember--stepping back.

As psychologists we have to question the natural.

We have to take things that are commonsense and explore them.

And one thing which just happens is, we're fascinated by

this stuff. We're fascinated by the lives

of celebrities. We're fascinated by the social

lives of other people. And it's an interesting

question to ask why. And this is one of the

questions which I'm going to deal with in the next couple of

lectures but before I get to the theory of social psychology I

want to talk about an individual difference.

So, we devoted a lecture early on--of a couple of weeks ago,

to individual differences across people in intelligence

and personality. I want to talk a little bit

about an individual difference in our social natures and then I

want people to do a test that will explore where you stand on

a continuum. That test is the piece of paper

you have in front of you. Anybody who doesn't have it

please raise your hand and one of the teaching fellows will

bring it to you. You don't know what to do yet

with it so don't worry. The test was developed actually

by Malcolm Gladwell who is a science writer--in his wonderful

book The Tipping Point. And as he introduces the test,

Gladwell recounts another experiment done by Stanley

Milgram, of course famous for his obedience work but he did a

lot of interesting things. And one classic study he did

was he gave a package to 160 people randomly chosen in Omaha,

Nebraska and he asked these people to get the package

somehow – and this was many years ago before the internet,

before e-mail – to get the package to a stockbroker who

worked in Boston but lived in Sharon,

Massachusetts. What he found was that most

people were able to do it. Nobody, of course,

knew this man but they knew people who might know people who

would know this man. So, most people succeeded.

Most people were able to get the packages to this man and it

took at maximum six degrees of separation,

which is where the famous phrase comes about that we're

all separated from another person by six degrees of

separation. This is not true in general.

This was a very--a single experiment done within the

United States, but the idea is appealing,

that people are connected to one another via chains of

people. But what Milgram found that was

particularly interesting was that in about half of the cases

these packages went through two people.

That is, if you plot the relationships between people--We

can take each person in this room,

find everybody you know and who knows you and draw a line,

but if we were to do this you wouldn't find an even mesh of

wires. Rather, you'd find that some

people are clusters. Some people are what Gladwell

calls "connectors." It's like air traffic.

Air traffic used to be everything flew to places local

to it but now there's a system of hubs,

Chicago O'Hare for instance or Newark where planes fly through.

Some people are hubs. Some people are the sort of

people who know a lot of people. Some people in this room might

be hubs, and it is not impossible to find out.

The piece of paper you have here is 250 names chosen

randomly from a Manhattan phone book.

They capture a range of ethnicities, different parts of

the world, different national origins.

Here's what I'd like you to do. And I'll give about five

minutes for this. Go through these names and

circle how many people you know. Now, the rules of this are,

to know somebody you have to--they have to know you back.

So, if it's a celebrity--Well, here--one of the names here is

Johnson. Now, I've heard of Magic

Johnson but Magic Johnson has never heard of me,

so I cannot circle it. On the other hand,

our department chair is Marcia Johnson.

She has heard of me, so I could circle it.

Go through and circle it. Circle all the people you know

who know you. Those are the people you're

connected to. If you know more than one

person with the same last name, circle it twice.

If you don't have this piece of paper and you want to

participate, please raise your hand and one of the teaching

fellows will bring it to you.

I'm going to talk a little bit more about this while people go

through this. The issue of connections

between people is intellectually interesting for many reasons and

might allow us to develop some generalizations about how people

interact. The game of Six Degrees of

Separation has, of course, turned into a famous

movie trivia thing revolving around the actor Kevin Bacon,

I think chosen just because it rhymes with "separation."

And the game of "Six Degrees of Kevin Bacon" is played by taking

any actor and computing how many steps it would take to get to

Kevin Bacon. And some computer scientists

have developed this. They've gone through each of

the quarter million actors and actresses on the international

movie database and computed their "Bacon number."

And the Bacon number is the number of steps it takes for

them to get to Kevin Bacon. So for instance,

Ed Asner was in the movie Change of--;"JFK" with Kevin

Bacon. So, Ed Asner has a Bacon number

of one. Elvis Presley was in the movie

"Change of Habit" with Ed Asner and that's his closest

connection to Kevin Bacon. So, Elvis Presley has a Bacon

number of two. It turns out that if you look

at the 2.5--sorry, the quarter million people on

the movie database and compute their Bacon number,

the average Bacon number is 2.8. That's how many steps your

average person is away from Kevin Bacon.

You could then, for any actor or actress,

compute the most connected one. So, the most connected one

would be the one for whom the quarter million are,

on average, the most connected to.

And the answer of the most connected actor or actress is

reasonably surprising. Does anybody want to guess?

I'll start you off with the wrong answer and this,

by the way, can be found on this web site.

It's not John Wayne. John Wayne has been in many

movies, 180 movies, in fact, over sixty years,

but he isn't well connected at all because mostly he was in

westerns so we saw the same people over and over again.

Meryl Streep also isn't it because Meryl Streep has the

misfortune of playing only in good movies.

[laughter] So, she has no connection with

people like Adam Sandler and John-Claude Van Damme.

[laughter] Guess. Any guesses?

Student: Christopher Walken

Student: Nicholas Cage Professor Paul

Bloom: Christopher Walken is a good one.

We could look it up. I only know a few names here.

Christopher Walken is not a finalist.

Nicolas Cage is an interesting case.

Has Nicolas Cage been in good movies?

I don't want to get--I'm going to get more controversial than I

want to. Student:

A guy who is one step above an extra.

He's like a B-list actor at best.

The most connected guy, and I think this shows that

you're right, is Rod Steiger.

He's the most connected actor in the history of acting because

it isn't that he's been in more movies than everybody else.

Michael Caine has probably been in the most movies of any person

on earth, but he's been in all sorts of movies.

He was in "On the Waterfront," "In the Heat of the Night," and

really bad movies like "Carpool."

He's been in dramas and crime serials, thrillers,

westerns, horror movies, science fiction,

musicals. Now, some people are like Rod

Steiger. So, some people in their

day-to-day lives have many interactions and I think one of

the things we know from interacting with people is we

can distinguish them from other people.

How many people have finished their things right now?

Okay. I know one person in the

department who is one of the most connected people I know on