were invited to a special summer camp in the deep woods of southeastern Oklahoma, at a

place called Robber's Cave State Park. None of the boys knew each other, although they

all came from similar backgrounds. They spent their days bonding over things like games

and swimming and treasure hunts, and in no time, they formed a tight friendly group.

They even came up with a name for themselves: the Rattlers.

But soon they began to notice something. No, not a guy in the woods with a hockey mask,

there was another group of boys also 11 of them, also the same age, that had been staying

at the other end of the park the whole time. The Rattlers never interacted with these other

boys, so they didn't know that those kids were also spending time bonding over games

and swimming and treasure hunts, and that they'd come up with a name for themselves,

too: the Eagles. But the Rattlers didn't like the look of the Eagles, oh, no, they didn't

like them using their baseball diamond or their dining hall.

And the feeling was mutual. It didn't take long for each group to start complaining to

the camp's counselors about the other gang, and eventually, they both said that they wanted

to set up a contest to determine once and for all which group was better. The counselors

were only too happy to comply, because as I'm sure you've figured out by now, those

counselors were actually researchers.

The man who set up what would be remembered as the Robber's Cave Experiment was Turkish

American social psychologist Muzafer Sherif. He was interested in what it would take for

rivals to overcome their differences and resolve their conflicts. Specifically, Sherif wanted

to test something called Realistic Conflict Theory. He hypothesized that conflict happens

when you combine negative prejudices with competition over resources, and the boys at

Robber's Cave were well on their way to proving him right.

Over the next couple of days, the Rattlers and the Eagles competed against each other

for prizes in a series of games, like tug-of-war and foot races, and soon, what started as

your basic trash talking and taunting and name-calling morphed into fist-fights, thefts,

and raids on each others' cabins. But then their dynamics changed or were changed for them.

After the games were over, the researchers integrated the groups and gave the kids shared

goals that they could only achieve through cooperation. The tide quickly turned. All

22 boys worked together to move a stalled truck that was carrying their food, they took

care of a partially felled tree that was deemed a danger to the camp, they collaborated in

setting up tents, even though they weren't given complete sets of equipment. While isolation

and competition made enemies of the strangers, shared goals and cooperation turned enemies into friends.

Over the past 39 weeks, we've learned a lot about ourselves, our emotions and our personalities,

how our minds can get sick, how we can help them get well again, why we can do vicious

things and then turn around and act like heroes. So maybe it's fitting that we wrap up this

course by looking at a couple of opposing forces that some consider the very definition

of human nature: aggression and altruism. Conflict and cooperation. You might think

of it as the psychology of war and peace, or simply, what we can all learn from a bunch of 12 year olds.

In psychology, aggression is defined as "behavior intended to hurt or destroy someone, something,

or even yourself." People aggress, as psychologists say, in all kinds of ways, verbally, emotionally,

and physically, and for lots of different reasons: out of anger, to assert dominance,

or as a response to fear. But that's just a glimpse into why someone might become aggressive.

Where does the aggression actually come from?

Like a lot of behaviors we've talked about it, it seems to emerge from that familiar

combination of biological factors, like genetic, neurological, and biochemical influences,

and our environment and experience. In terms of genetic influences, studies of twins, and

yes, Crash Course Psychology might have been called Crash Course Studies of Twins, showed

that if one identical twin has a violent temper, often the other one does, too, but fraternal

twins are much less likely to be so similar.

Neurologically speaking, no single area of the brain controls aggression, but certain

areas like the limbic system do appear to facilitate it. Research on violence and criminality

has also revealed a link between aggression and diminished activity in the frontal lobes,

which play a vital role in impulse control.

And finally, our aggressiveness can be influenced by our own biochemistry, hormones like testosterone

and glucocorticoids and pheromones have all been implicated in animal models of aggression.

It's a little trickier in humans, it's a lot trickier in humans, but it's highly likely

that our hormones are intimately linked with feeling and showing aggression.

Obviously, aggression isn't just about biology. Psychological and cultural factors also play

an important role, as does the power of the situation. For example, there's the Frustration-Aggression

Hypothesis, the simple idea that people become aggressive when they're blocked from reaching

a goal. To demonstrate, consider the not-very aggressive sport of baseball. There's a study

that analyzed 44 years worth of baseball stats, and focused on the more than 27,000 incidents

when a pitcher hit a batter with a ball. It turned out that this was most likely to occur

if the pitcher was frustrated by a recent home run or if one of his own teammates had

been hit by a pitch in the previous inning.

But we also learn aggression by watching others. Like, if you grew up watching your parents

throw popcorn and jeering lewdly at their most hated soccer team, you might have learned

something from their behavior. So combine all of those biological factors and funnel

them through a particular person with a particular history in a particular situation, and you

can begin to see how aggression can have many roots that grow together.

Thankfully, though, humans are more than their bad tempers. While some things in people will

leave us annoyed and angry, others breed friendship and affection. So yes, there are positive

topics in social psychology, like altruism, our selfless, even self-sacrificing regard

for the welfare of others. This could be something as simple as jumpstarting a stranger's car

or as heroic as running into a burning building to save someone. But if being altruistic is

so awesome, why aren't we all that way all the time? Or maybe the better question is,

why do we ever do anything selfless, like, what's in it for us?

In the late 1960s, social psychologists Bibb Latane and John Darley conducted a series

of experiments examining when and why we help others. In one experiment, they placed a subject

in a room, sometimes alone, sometimes with two other subjects, and sometimes with two

actors posing as subjects. Then, they simulated an emergency by filling the room with smoke

and waited to see if the subject would do anything to alert the others or help themselves.

If the subject was alone, they'd report the smoke 75% of the time. But subjects in a group

of three only spoke up 38% of the time. And when they were stuck in the room with two

oblivious actors, only 10% of the participants said anything to the others. Darley and Latane

found that people typically helped others only if they noticed the incident, interpreted

it as an emergency, and then finally, assumed responsibility, and all of these things were

much more likely to occur if a person was alone, while the presence of others deterred

the person from helping.

This kind of diffusion of responsibility referred to as the bystander effect, can weaken our

instinct for altruism. The bystander effect is a bit like the concept of social loafing

that we talked about. If you're around other people, it's easier to think that someone

else is going to pick up the slack or in this case, come to the rescue.

When people do decide to help others, they may do it for a number of reasons. One perspective

is that we tend to help others mainly out of self-interest. By this thinking, helping

really isn't altruistic at all, and instead, our actions boil down to a sort of cost-benefit

analysis. Like, maybe we'd turn in a lost wallet because we're hoping for a reward or

we pitch in on a project at work because we think we'll get recognized and promoted by

our bosses. Social psychologists contextualize these kinds of examples in the broader theory

of social exchange. When it comes to doing things for other people, we're always trying

to maximize our personal rewards while minimizing our costs. But social exchange doesn't have

to be as selfish as that, it can also mean that we act altruistically because we expect

that the people we help will go on to help others, so if we give someone a hand changing

a tire, maybe they'll stop next time they see someone else, maybe even us, broken down

on the side of the road. You might know this concept, sometimes it's called the norm of

reciprocity, sometimes it's called paying it forward.

And then there's the social responsibility norm, which is the simple expectation that

people will help those who depend on them, like any parent can expect to give more help

than they're going to receive from young children. That's just part of being a parent. Naturally,

the world would be a delightful place if altruism were the standard for human behavior, but

then, psychology wouldn't be nearly so interesting.

In some ways, you might say that what fuels conflict is the opposite of altruism: self-interest.

Social psychologists view conflict as any perceived incompatibility of actions, goals,

or ideas. That could mean two nations fighting over a border, sparring religious or political

groups, or you and your boo fighting over whose turn it is to do the dishes.

And in a weird conundrum of human behavior a lot of conflicts arise from what psychologists

call "a social trap," where people act in their own short term self-interest, even though

it takes a toll on the larger group and on themselves over the long-term. You see this

kind of thing all the time on an individual scale, like in a crime movie, when a criminal

just betrays all of his criminal friends to get the big payout, it doesn't turn out very

well for him in the end. But on a larger scale, you can find social traps taking their toll

on the environment, like when we poach elephants to sell their ivory or cut down old growth

forests to make a quick buck in the lumber market. Either way, when self-interest succeeds

in wrecking the collective interest by, say, depleting some limited resource, it becomes

easy to start viewing our neighbors as competitors, taking us right back to the ingroup vs. outgroup

mindset that we all know causes big problems.

So as long as there's self interest, there's gonna be conflict.

But before you get all down on humanity, remember those Robber's Cave boys. They were ready

to go full-on Lord of the Flies before shared goals forced them to cooperate and ultimately,

make peace. The power of cooperation to make friends of former enemies is one of the most

hopeful areas of psychological research. If greed and self-interest can destroy the world,

perhaps cooperation can save it.

Today, you learned about the Robber's Cave experiment and what it taught us about realistic

conflict theory and how shared goals can overcome conflict. We looked at the physical and environmental

triggers of aggression, and the frustration-aggression hypothesis. You also learned about altruism,

the bystander effect, and when we are more or less likely to help a person in need, and

also about the social exchange theory, the reciprocity norm, the social responsibility

norm, and social traps.

Thanks for watching, especially to all of our Subbable subscribers who make Crash Course

possible. To find out how you can become a supporter, just go to Subbable.com, and please

remember to go to YouTube.com/CrashCourse and subscribe for more future Crash Courses

in the future.

This episode was written by Kathleen Yale, edited by Blake de Pastino, and our consultant

is Dr. Ranjit Bhagwat. Our director and editor is Nicholas Jenkins, the script supervisor

and sound designer is Michael Aranda, and the graphics team is Thought Cafe.