Are you sure it's safe here?

It's fine.

There's nobody here.

This place has been abandoned for years.

Hey, Craig.

[craig screams] Oh, you're watching the old horror movie, eh?

Shh.

You know what's interesting about horror movies?

I'm trying to enjoy the movie.

You know, that's just the thing.

Fear is usually associated with unpleasant situations, situations we want to avoid, so why do we like horror movies?

Why do we like to be afraid?

Can we talk about this later?

Sure.

[woman screams] [men scream] What is fear?

Fear is a combination of processes that happen when we're under immediate threat.

This is David Zald, professor of psychology and psychiatry at Vanderbilt University.

And that's going to include a subjective feeling.

What we think about when we think of an emotion, it's going to have to do with physical responses, for instance, the hair on our arms standing up, changes in our heart rate, our breathing, possibly freezing, or wanting to flee and run away.

And then it also is going to have an effect on facial expressions, the classic response where the eyes become really wide.

And that ends up communicating that information to other people, that we're afraid.

Can we both do that face right now?

[both fake screaming] That was actually pretty good.

Thanks.

I'm pretty good at being afraid.

I'm a lousy actor, but you've got potential.

Well, thanks.

I'm in front of the camera a lot.

So what's actually going on inside of our head when we're afraid?

Well, David Zald uses neuroimaging techniques to map the different areas of the brain that respond when we're afraid.

Well, one of the earliest findings we had was not specifically geared towards fear.

We were just trying to map out what caused certain areas of the brain to activate.

And one of them is an area called the amygdala, this almond shaped area in the temporal lobe.

There are actually two amygdalae, one in each hemisphere of the brain, and they play a primary role in decision making and memory formation during emotional events.

Early on, we just started exposing people to different things.

One of the things we tried, because we thought it might work, were really horrendous smells.

Woo.

Oh.

Did you shower today, Matt?

What was that?

Oh.

What am I smelling?

To this day, that seems to be one of the best ways to activate the area.

It just lights it right up.

Unlike our other senses, our sense of smell shares a number of neural pathways with the amygdala.

And since the amygdala plays such an important role in the formation of memory, smell can be a good way to conjure up past emotions, stinky, stinky emotions.

So if a bad smell is associated with a bad memory, the amygdala will trigger our fear response.

The amygdala is like the fear command center for the brain, giving us the willies and spooking us and making us feel all jiggy with it.

No, not exactly.

I'm not sure, I'm not sure what jiggy with it is, necessarily.

It's wrong even to talk about something like the amygdala as a single brain region and treat that, oh, that's fear itself.

It's much more complicated.

That processing going on in the amygdala is very much tied to what's going on in some brain stem areas, what's going on in some cortical areas.

And just trying to get a handle on what each component of those circuits is contributing is a lifelong puzzle for us in neuroscience.

So a whole host of brain regions contribute to our sense of fear.

Yup, and it's not just what's going on our brain.

Our perception of fear in others also plays a role.

The other thing that I was not expecting was the extent to which this same area of the amygdala lights up when you see someone who's afraid.

So you made that fear face earlier.

That will cause my own amygdala to resonate with that.

People talk about it as emotion contagion, where you actually are catching some of the emotion of the person.

We can see this when we watch horror movies.

When we see someone scared on the big screen, it makes us feel scared, too.

And if you think about it, it's actually useful for me to know that you're afraid of something because if you're afraid of something, I could be at risk, too.

I better look around and say, what's this guy reacting to?

And I don't think many of us expected that, and that's been something now that people have seen over and over again in the literature as something that's not just about your experience of the fear, but your perception of it in someone else.

[screams] Well, it seems like fear is a good thing in survival situations.

Maybe that's why we like it?

It's both good and bad.

It's good in that it's incredibly protective for us.

If we're not afraid of things, we do some really stupid things.

We're capable as humans of making some absolutely disastrous decisions about what to do.

Oh, that's a pretty ocean.

I'm going to walk at it now.

Yay.

Now I'm dead.

On the other hand, it can be a bad thing when it starts to run amok or go beyond what rationally make sense.

Yeah, like the time I was afraid of the pinata at my nephew's birthday party, and I paid the mailman to take it to Canada.

That didn't make any sense.

For instance, someone who becomes so terrified flying, even though they can look and see that there are very few flights that crash, that they're far more likely to die in a car accident than in a plane crash.

And once you start getting that sort of fear, it can be incredibly limiting and interfere with the person's life.

OK, that sounds pretty bad.

How can something that can have such a detrimental effect on our lives also be enjoyable?

Fear's so fascinating because it both makes total sense at times, and at times makes so little sense.

And it can be so out of our control, and to me that's just fascinating.

OK, OK. We've been talking a lot about situations where we don't like to be afraid, but what about when we do?

What's going on when that happens?

Well, there are lots of things going on, and that's sort of the part of what's cool about it.

One is that amygdala response, which is the fear response.

Here's Johnny.

[gasps] It's going to help get your adrenaline rushing.

It's going to be pushing that anxiety part of things.

The rush of adrenaline increases your heart and respiratory rate and widens your blood vessels, allowing more oxygen-rich blood to surge throughout your body, giving you the strength to fight or flee from a dangerous situation.

Neurons throughout the brain are firing away as it gets all this stimulation going on, and then you've also got afterwards a rush that comes with relief that I did that, I accomplished that.

And probably there's some endogenous opiates that are getting released when you do that as well.

And so the extent of things going on is really quite amazing when you think about the number of things the brain's accomplishing.

This is part of the thrill of it, that there's so much that can be attended to at one time that it is totally absorbent.

Maybe fear is like a cognitive symphony in our heads with all the highs and lows of a real symphony.

It makes the hair on our neck stand up, our blood pressure rise.

We get jiggy with it.

For millions of years, fear has kept our ancestors safe and away from danger, so the feeling of being afraid can be closely associated, if not inexorably linked, to the feeling of being alive.

Maybe that's what so great and terrifying about fear.

The depth of the emotion is what makes it enjoyable, so under the right circumstances, being afraid can be thrilling.

A love of fear, whether it's a love of roller coasters or skydiving or scary movies, is in a way, a love of life.

Yeah.

So what do you guys think?

Do you like being afraid?

Do you seek out fear?

Are you a thrill seeker?

Let us know in the comments.

In our last video, we visited with Ken Dunn at City Farm, and you guys had something to say about it.

This is what we have to say about what you said about it.

Jager Mitchell pointed out that Malthus was wrong about us hitting a brick wall in terms of food production.

This is in reference to when Ken Dunn mentioned Malthus in the beginning of the video.

Thomas Malthus was a thinker in the 18th and 19th century who predicted that the growth of population would outpace our ability to feed ourselves.

This would lead to a catastrophic population collapse, which obviously didn't happen because Malthus did not foresee the advancement of technology, which allowed our rate of food production to increase.

However, there's no single solution to our food problems, but to avoid a Malthusian catastrophe, we should probably use a wide array of technologies and techniques to feed ourselves in the future, including urban farming, and maybe eating bugs and maybe you should try the mac and cheese.

It's really good.

Andybearchan asked how air pollutants and exhaust in cities affect urban gardens.

Well, living in Chicago myself, I've never noticed many problems with exhaust, but these urban gardens aren't necessarily near heavy traffic areas.

They're often in blighted neighborhoods that don't see much traffic.

There's only been limited studies in how air pollutants affect crops grown in cities, but usually they wash right off the plants.

Easier than some of the chemical pesticides used in large scale commercial farming.

The bigger danger in growing in an industrial city is the toxins in the soil.

City Farm caps their lots with a clay liner that separates the crops and the compost they grow in from the contaminated soil underneath.

Ljmasternoob asked how climate change will affect urban farming.

I understand that you don't know the answer because you are a noob.

It's hard to say how climate change will affect urban farming.

The more erratic, more extreme weather predicted by climate scientists certainly won't help urban farming, but it won't help traditional farming either.

And we will feel the detrimental effects of climate change more acutely when they start to affect the large scale farming operations because that's where we get most of our food at the moment.

Benjamin Williamson asked if Ken Dunn was the same guy we interviewed in our recycling playlist.

Yes, he was, and we got to go on one of his recycling routes, and you can check out that video in the description.

Youlostthegame97 said Wheezy is looking thinner.

Oh, thanks.

More comments like that, please.

I've been jogging four times a week and counting my calories and trying to eat a little healthier.

It's that simple.

Thanks for watching.

If you want to support our show, you can subscribe to our Patreon page.

Or you can join the digital street team and get out there and promote the show.

Or just shout at the window.

That's probably not going to-- It's up to you how you want to do it.

It's not going to be that effective.

We encourage creativity, and self-reliance, independence, and freedom.

And health.

And, uh-- Healthy choices.

And I think we're done.

Bye.

Thanks for watching.