Latest / Daniel and Kelly’s Extraordinary Universe / Halloween Special: Zombies and Ghosts

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Halloween Special: Zombies and Ghosts · Daniel and Kelly’s Extraordinary Universe

• 0:06
  Speaker 1: Happy Halloween everyone. This is my favorite time of year.
• 0:10
  Speaker 1: The weather's cool, the leaves are changing color here in Virginia,
• 0:14
  Speaker 1: and creepy stuff is in. So this week Daniel and
• 0:18
  Speaker 1: I are geeking out about zombies and ghosts. The zombies
• 0:23
  Speaker 1: I'm going to be talking about aren't like creatures who
• 0:26
  Speaker 1: have been infected by viruses that bring the creatures back
• 0:29
  Speaker 1: from the dead in search of delicious brains. But what
• 0:32
  Speaker 1: are often called zombies in pop science are creatures that
• 0:36
  Speaker 1: are infected by parasites, and then those parasites manipulate their
• 0:41
  Speaker 1: living creatures living hosts into acting in weird ways that
• 0:45
  Speaker 1: benefit the parasite while often hurting the host. But one
• 0:50
  Speaker 1: of the hard things about studying seemingly zombified creatures is
• 0:55
  Speaker 1: that behaviors can change when someone is infected for a
• 0:59
  Speaker 1: lot of reasons. Just because it sounds like a behavior
• 1:03
  Speaker 1: can benefit a parasite, that doesn't necessarily mean that it does.
• 1:08
  Speaker 1: In fact, sometimes we've looked into seemingly zombified creatures and
• 1:12
  Speaker 1: when we look into them more closely, the story that
• 1:15
  Speaker 1: we had been telling ourselves falls apart. Let's think through
• 1:18
  Speaker 1: why this can be so tough, all right, So, imagine
• 1:21
  Speaker 1: you're a kid who's home with a fever. Who does
• 1:24
  Speaker 1: that fever benefit all right, Well, maybe it benefits the
• 1:27
  Speaker 1: sick kid. If the high temperature makes it hard for
• 1:30
  Speaker 1: the bacteria or something to survive and grow, all right,
• 1:33
  Speaker 1: that's option one. Option two, maybe neither benefits. So if
• 1:37
  Speaker 1: the fever gets too high, then maybe that's bad for
• 1:40
  Speaker 1: the kid and it's bad for the bacteria. Anyone who
• 1:43
  Speaker 1: has allergies knows that sometimes immune systems overact and do
• 1:46
  Speaker 1: things that are not beneficial. So there are some instances
• 1:49
  Speaker 1: where something changes about the infected individual that's really not
• 1:53
  Speaker 1: good for the individual or the bacteria. Third option is
• 1:57
  Speaker 1: that maybe the change that happens after infection benefits the parasite.
• 2:01
  Speaker 1: So say a kid comes home with a fever, some
• 2:04
  Speaker 1: parent is definitely going to bend over and give that
• 2:07
  Speaker 1: kiddo a kiss on the forehead to see how warm
• 2:10
  Speaker 1: their forehead is. And if my experience as a parent
• 2:14
  Speaker 1: is any indication that is exactly when the kid is
• 2:17
  Speaker 1: going to sneeze directly into your face and often directly
• 2:21
  Speaker 1: into your mouth. So you could tell a story about
• 2:24
  Speaker 1: a fever being away that parasites are bacterial infections. Transmit
• 2:29
  Speaker 1: from kids to their parents. So we've come up with
• 2:32
  Speaker 1: a fairly plausible story. And I was just spitballing here,
• 2:35
  Speaker 1: but the point is that it's easy to tell a
• 2:37
  Speaker 1: story that sounds kind of plausible. So when you see
• 2:41
  Speaker 1: a story about a creature responding in some way after
• 2:44
  Speaker 1: it gets sick, it's important to consider all the different
• 2:47
  Speaker 1: reasons why that could be happening. So today we're going
• 2:51
  Speaker 1: to start our Halloween show with the chat about toxoplasma
• 2:54
  Speaker 1: GANDHII and how it changes the behavior of the creatures
• 2:57
  Speaker 1: it infects, and we're going to evaluate how good the
• 3:00
  Speaker 1: evidence for these claims actually are. The disconnect between the
• 3:04
  Speaker 1: strength of the claims about toxoplasma gandhi i'm manipulating the
• 3:09
  Speaker 1: behavior of the creature and effects and the actual evidence
• 3:13
  Speaker 1: is kind of spooky. And parents, we talk a bit
• 3:17
  Speaker 1: about the birds and the bees when describing the life
• 3:19
  Speaker 1: cycle of this parasite. Nothing too gratuitous or anything. But
• 3:23
  Speaker 1: now is your chance to pick a different episode for
• 3:26
  Speaker 1: the car ride with your kids if you think that's necessary.
• 3:29
  Speaker 1: All right, Welcome to Daniel and Kelly's Extraordinary and spooky universe.
• 3:50
  Speaker 2: Hi, I'm Daniel, I'm a particle physicist, and I'm wearing
• 3:53
  Speaker 2: a Halloween costume chosen by my daughter.
• 3:56
  Speaker 1: I'm Kelly Wiener Smith, and I'm excited because this is
• 3:59
  Speaker 1: the best time a year to not be in California,
• 4:02
  Speaker 1: because the leaves are changed in color and it's gorgeous
• 4:05
  Speaker 1: here in California. Just doesn't have anything on Virginia this
• 4:07
  Speaker 1: time of year. Sorry, Daniel.
• 4:10
  Speaker 2: Have you been to California in October? The air is
• 4:13
  Speaker 2: wonderfully crisp, it still never rains. It's pretty nice.
• 4:17
  Speaker 1: I lived there, I've been there in the fall, and
• 4:20
  Speaker 1: it's not as good as Virginia.
• 4:22
  Speaker 2: All Right, I'm gonna have to come gather some data
• 4:24
  Speaker 2: on Virginia so I can make intelligent comments rather than
• 4:27
  Speaker 2: just take cheap potshots.
• 4:29
  Speaker 1: Sounds good, although you're coming to visit in March, which
• 4:31
  Speaker 1: is maybe not the best Virginia month.
• 4:33
  Speaker 2: But oh, I see right.
• 4:35
  Speaker 1: I'm already hedging my bets.
• 4:37
  Speaker 2: You're making excuses for it already.
• 4:39
  Speaker 1: Yeah, that's right, that's right.
• 4:42
  Speaker 2: Well. I love Halloween also because I usually teach my
• 4:45
  Speaker 2: class in costume, and today I give an exam in
• 4:48
  Speaker 2: my class, and I told them if they came to
• 4:51
  Speaker 2: the exam in full costume. They get extra credit.
• 4:54
  Speaker 1: What is the best costume your student has ever worn
• 4:56
  Speaker 1: to class?
• 4:58
  Speaker 2: Somebody came in one of those huge, bl low up
• 5:00
  Speaker 2: dinosaur costumes, took up like three rows of seats and
• 5:04
  Speaker 2: took their exam. It's hard to fill out a scanshow
• 5:06
  Speaker 2: with the little t rex arms, but they did it.
• 5:08
  Speaker 1: That's commitment. That's actually my daughter's Halloween costume this year.
• 5:11
  Speaker 1: We got her one of those. I can't wait to
• 5:13
  Speaker 1: see how she looks at it. She's gonna have a blast.
• 5:15
  Speaker 1: And I am a giant moth because I like insects,
• 5:18
  Speaker 1: and so I got a moth onesie so that I
• 5:20
  Speaker 1: can still wear it for other things, because I don't
• 5:22
  Speaker 1: want to spend fifty dollars on something I'm gonna wear once.
• 5:24
  Speaker 1: So yeah, it's gonna be a good Halloween in the
• 5:26
  Speaker 1: Wienersmith House.
• 5:27
  Speaker 2: So you're just gonna hang out in that onesie the
• 5:29
  Speaker 2: rest of the year.
• 5:30
  Speaker 1: Also, yeah, no, probably I might decide that I really
• 5:33
  Speaker 1: like being a moth and maybe that's all I'm gonna.
• 5:35
  Speaker 2: Wear Sunday Moth Day at the Wienersmith Farm.
• 5:38
  Speaker 1: Yeah, just one more way I embarrass my children. The
• 5:42
  Speaker 1: list is getting long.
• 5:43
  Speaker 2: Well, I give my daughter free rain to choose my costume.
• 5:45
  Speaker 2: I said, whatever costume you pick, I'm gonna wear, which
• 5:48
  Speaker 2: is why I'm now an alien abducting human.
• 5:53
  Speaker 1: That's fantastic. How hard was it to make that costume?
• 5:57
  Speaker 2: Oh no, she bought it for sure. Oh and I
• 6:01
  Speaker 2: don't think she listens to the podcast, but she hears
• 6:03
  Speaker 2: me talk about aliens enough to know that the alien
• 6:06
  Speaker 2: theme was going to suit me.
• 6:07
  Speaker 1: Excellent. It's nice when your kids know you pretty well
• 6:10
  Speaker 1: a little bit. I can't get my husband to wear
• 6:12
  Speaker 1: a costume at all.
• 6:13
  Speaker 2: What.
• 6:14
  Speaker 1: No, He's never worn a costume for Halloween as far
• 6:16
  Speaker 1: as I know.
• 6:17
  Speaker 2: Why is he anti costume?
• 6:18
  Speaker 1: He's so creative, he's anti fun. I don't know.
• 6:22
  Speaker 2: Come he writes a webcomic. He can't be anti fun.
• 6:26
  Speaker 2: He makes people laugh. He can't be anti fun.
• 6:29
  Speaker 1: I don't know what to tell you, man, he's anti
• 6:31
  Speaker 1: fun on Halloween. I guess I tried to get a
• 6:33
  Speaker 1: family costume and he was absolutely no on the family
• 6:36
  Speaker 1: costume thing.
• 6:37
  Speaker 2: Maybe you should all dress up as him one year,
• 6:39
  Speaker 2: then he's in costume.
• 6:40
  Speaker 1: I like that, Eric, Thank you. I'm making a note
• 6:44
  Speaker 1: in my Google calendar for next year, everybody dresses up
• 6:46
  Speaker 1: like Zach.
• 6:47
  Speaker 2: But we are not here today just to so discord
• 6:49
  Speaker 2: in Kelly's family. We are here to talk about Halloween.
• 6:53
  Speaker 2: And because we are science nerds and we'd like to
• 6:55
  Speaker 2: dig deep into science of everything, we're here to talk
• 6:57
  Speaker 2: about the science of Halloween, specifically zombies and ghosts, the
• 7:02
  Speaker 2: biology and physics of Halloween.
• 7:05
  Speaker 1: I am so excited about this episode, and I'm also
• 7:08
  Speaker 1: exciting because it gives me a chance to talk about
• 7:10
  Speaker 1: probably the most famous parasite that manipulates the behavior of
• 7:14
  Speaker 1: its host, Toxoplasma gandhi. And as someone who got their
• 7:17
  Speaker 1: PhD in this field, I am constantly asked about this parasite,
• 7:21
  Speaker 1: and I am constantly frustrated by the disconnect between what
• 7:24
  Speaker 1: people think we know and what the evidence actually supports. So,
• 7:27
  Speaker 1: just like usual, I am going to throw water on
• 7:31
  Speaker 1: everyone's fun. But there's still some cool things to learn
• 7:34
  Speaker 1: along the way, so it'll be okay.
• 7:36
  Speaker 2: So you're saying it's not just physics that has like nonsense,
• 7:39
  Speaker 2: popsy clickbait misinformation, it's also biology.
• 7:42
  Speaker 1: Oh my gosh, it's also biology. I mean, we're lucky
• 7:44
  Speaker 1: because we have Ed Yong who writes about parasites that
• 7:47
  Speaker 1: manipulate host behavior, and he's like, super good about evaluating
• 7:51
  Speaker 1: the evidence, but not everybody is quite that careful. And
• 7:53
  Speaker 1: it seems to have emerged in the public consciousness that
• 7:56
  Speaker 1: Toxoplasma gandhi absolutely makes rodents attract to cats and gets
• 8:00
  Speaker 1: the meetn by it and changes human behavior and all
• 8:03
  Speaker 1: sorts of weird pays.
• 8:04
  Speaker 2: But let's start with the connection of Halloween. Do you
• 8:07
  Speaker 2: chose this paraside because it kind of makes things into zombies?
• 8:11
  Speaker 2: Is that right? What's the zombie connection between Toxoplasma gandhi
• 8:15
  Speaker 2: and Halloween?
• 8:16
  Speaker 1: All right, So every field has their like thing that
• 8:19
  Speaker 1: everybody fights about and they get upset about, and the
• 8:22
  Speaker 1: use of the phrase zombie really divides my field. So
• 8:25
  Speaker 1: there are some people who are like, well, if you
• 8:28
  Speaker 1: call it a zombie, people are going to think that
• 8:30
  Speaker 1: the animal that got infected died and then came back
• 8:33
  Speaker 1: from the dead. And I'm like, I just feel like
• 8:35
  Speaker 1: you're not giving the general public enough credit, Like, I
• 8:37
  Speaker 1: don't think anyone thinks that they're being brought back from
• 8:40
  Speaker 1: the dead. What do you think is that fair to say?
• 8:42
  Speaker 2: Yeah, that's a great question. I think my first thought
• 8:44
  Speaker 2: when I hear, zombie is definitely the walking dead, right,
• 8:47
  Speaker 2: like these folks have been killed and now they're like
• 8:49
  Speaker 2: shuffling around. But I've seen enough zombie movies and science
• 8:53
  Speaker 2: fiction in general to appreciate this like a broadening of
• 8:55
  Speaker 2: the category. And you know, people being infected by some
• 8:58
  Speaker 2: sort of disease which makes them want to eat brains
• 9:00
  Speaker 2: and shuffle around and like are they or not doesn't
• 9:03
  Speaker 2: seem to be really crucial to being a zombie. It's
• 9:05
  Speaker 2: more like, you know, drooling a lot, shuffling along and
• 9:08
  Speaker 2: wanting to eat brains. So it'd be pretty cool if
• 9:11
  Speaker 2: there was a real life biological effect that made people
• 9:15
  Speaker 2: act like the zombies in the movies we see. I
• 9:17
  Speaker 2: think people would accept that as a zombie.
• 9:19
  Speaker 1: Okay, well that's not what I'm talking about today. No,
• 9:24
  Speaker 1: it's not like that. I still feel like if you
• 9:26
  Speaker 1: use the word zombie, then people think like, okay, some
• 9:29
  Speaker 1: infectious something that's changing the behavior as high decked the behavior,
• 9:33
  Speaker 1: And that's really all we mean today. And so it's
• 9:36
  Speaker 1: a way to try to make the topics sort of
• 9:38
  Speaker 1: accessible and exciting to a general public. But it has
• 9:41
  Speaker 1: its drawbacks because I guess, just like any analogy. It's
• 9:44
  Speaker 1: not perfect and it falls flat in some ways, but
• 9:46
  Speaker 1: I like it anyway.
• 9:47
  Speaker 2: And just to set the context a little bit more like,
• 9:49
  Speaker 2: I can be infected by some bug or even some parasite,
• 9:53
  Speaker 2: but doesn't change my behavior. I mean, maybe I get sick,
• 9:55
  Speaker 2: but it doesn't make me like change what I eat
• 9:57
  Speaker 2: or decide I'm gonna study biology instead of physics or
• 10:00
  Speaker 2: some crazy mind bending misdecision in life, or live in
• 10:04
  Speaker 2: Virginia or something insane. Right, I'm still who I am mentally.
• 10:08
  Speaker 2: So you're saying that there's a category of bugs or
• 10:11
  Speaker 2: parasites whatever that also change the way your brain works,
• 10:14
  Speaker 2: and so the decisions.
• 10:15
  Speaker 1: You make, yes, and those decisions that you make are
• 10:17
  Speaker 1: decisions that benefit the parasite and may or may not
• 10:20
  Speaker 1: benefit you. So you know the eating brains in the
• 10:23
  Speaker 1: zombie movies, you know, you take a bite out of
• 10:25
  Speaker 1: somebody and that transmits the parasite in the saliva to
• 10:28
  Speaker 1: another individual. And maybe the eating brains is a side effect.
• 10:30
  Speaker 1: I don't know, but so it's got to benefit the
• 10:32
  Speaker 1: parasite in some way, and often at the expense of
• 10:35
  Speaker 1: the host.
• 10:35
  Speaker 2: Okay, So now I'm mentally imagining, you know, the rat
• 10:38
  Speaker 2: and ratitude that sits on the guy's head and pulls
• 10:40
  Speaker 2: on his hair and controls him. Basically, you're like being
• 10:43
  Speaker 2: driven by this thing. You're not really making your own
• 10:45
  Speaker 2: decisions and your own best interest anymore. You're being used
• 10:48
  Speaker 2: as a vessel for whatever it is that's infected you,
• 10:51
  Speaker 2: and it's controlling you.
• 10:53
  Speaker 1: Yes, And it's usually not all or nothing. It's usually
• 10:56
  Speaker 1: like a very specific Sometimes it can be a feature
• 10:59
  Speaker 1: of the way that you look, or a certain set
• 11:01
  Speaker 1: of behaviors that change. It's often when we're talking about
• 11:03
  Speaker 1: actual cases where parasites are manipulating the behavior of the
• 11:06
  Speaker 1: creature they infected, it's actually kind of targeted as opposed
• 11:09
  Speaker 1: to like a wholesale shambling along change in everything that
• 11:12
  Speaker 1: you do. But yes, you're essentially to some extent under
• 11:15
  Speaker 1: the control of another individual.
• 11:17
  Speaker 2: On that topic, one of my favorite Halloween costumes ever
• 11:20
  Speaker 2: is the rat from Ratitui sitting on somebody's head, and
• 11:22
  Speaker 2: this nerdy engineer actually designed one where the rat is
• 11:25
  Speaker 2: like moving and controls the person like a puppet or
• 11:29
  Speaker 2: really hilarious. That's awesome, But let's not talk about Ratituvi
• 11:32
  Speaker 2: and fictional zombies anymore. Let's talk about the actual science.
• 11:36
  Speaker 2: So in what way does Toxoplasma gandhii fulfill this category
• 11:40
  Speaker 2: of zombie ish kind of takeovers?
• 11:42
  Speaker 1: All right, Well, first let's just talk about some background
• 11:45
  Speaker 1: on this organism. It is sometimes called the most successful
• 11:49
  Speaker 1: parasite on the planet. It can infect just about any
• 11:51
  Speaker 1: warm blooded animal, so beluga whales have it, hyenas have it,
• 11:55
  Speaker 1: rodents have it, humans have it, birds have it. It
• 11:59
  Speaker 1: infects a lot of stuff.
• 12:00
  Speaker 2: But what is it? Is it like a little worm?
• 12:02
  Speaker 2: Is it a bug?
• 12:03
  Speaker 1: It's like a little protozoan parasite, so it's eukaryotic, but
• 12:07
  Speaker 1: it's very small, single cells.
• 12:09
  Speaker 2: So it's a single cell, has a nucleus. It's basically
• 12:12
  Speaker 2: a tiny little critter.
• 12:13
  Speaker 1: It is basically a tiny little critter, that's right. And
• 12:15
  Speaker 1: so a really quick jargon distinction which might be helpful
• 12:19
  Speaker 1: is that, you know, usually when people talk about pathogens,
• 12:22
  Speaker 1: they're talking about bacteria and viruses, things that give you
• 12:25
  Speaker 1: like the cold and the flu. When they're talking about parasites,
• 12:28
  Speaker 1: we're usually talking about eu carryouts. So organisms with like
• 12:31
  Speaker 1: a nucleus and a cell wall and stuff, and so
• 12:33
  Speaker 1: Toxoplasma gandhii is a parasite, not a pathogen. Not a pathogen, okay,
• 12:39
  Speaker 1: And so.
• 12:39
  Speaker 2: It infects a huge number of things worldwide, Like do
• 12:42
  Speaker 2: you have it? Do I have it?
• 12:43
  Speaker 1: So there's probably like a eleven percent chance that either
• 12:46
  Speaker 1: one of us happens to have it.
• 12:48
  Speaker 2: What that's very high.
• 12:49
  Speaker 1: Yeah, in the US, about one in ten people have it. Worldwide,
• 12:52
  Speaker 1: about one in three people have it. And there's a
• 12:55
  Speaker 1: bunch of different ways that you can get it. And
• 12:56
  Speaker 1: this is what makes the parasite so successful and so
• 12:59
  Speaker 1: mind blowing is that those parasites have like one or
• 13:01
  Speaker 1: two paths to their next host. Toxoplasma gandhi is like
• 13:05
  Speaker 1: amazing in its diversity. So let's start with cats. So
• 13:08
  Speaker 1: cats are in any different species of cat is a
• 13:11
  Speaker 1: very important kind of host for Toxoplasma gandhi. This is
• 13:15
  Speaker 1: where the parasites get together and have sex. So it's
• 13:17
  Speaker 1: called the definitive host, and I think of it as
• 13:19
  Speaker 1: that's definitely where they're going to be having sex. And
• 13:22
  Speaker 1: that's how I remember that. You're welcome everyone, and so
• 13:25
  Speaker 1: like we can have a whole episode actually on why
• 13:27
  Speaker 1: evolutionary biologists think sex is beneficial in general, But it's
• 13:30
  Speaker 1: something about mixing genetic material up so that you can
• 13:33
  Speaker 1: have some diversity for dealing with things that might be
• 13:35
  Speaker 1: happening in the environment or for battling the host immune system.
• 13:38
  Speaker 2: And so these guys can only reproduce inside the guts
• 13:41
  Speaker 2: of cats, or there's something about that environment that's better
• 13:45
  Speaker 2: and they can do it elsewhere also, or is it
• 13:46
  Speaker 2: just really only inside cat guts.
• 13:49
  Speaker 1: That is only where sexual reproduction happens. So we're going
• 13:52
  Speaker 1: to talk a little bit later about places where they
• 13:54
  Speaker 1: can do asexual reproduction where you can essentially just think
• 13:57
  Speaker 1: they're like copying and pasting the exact same cop be
• 14:00
  Speaker 1: over and over and over again. So this is where
• 14:02
  Speaker 1: they get to like swap genetic material to hope to
• 14:05
  Speaker 1: like stay ahead of the immune system arms race they're
• 14:07
  Speaker 1: going through with the other animals that they're trying to infect.
• 14:10
  Speaker 2: And what is it about cat guts that's so especially romantic?
• 14:13
  Speaker 1: Mm? Wow, that's a great question.
• 14:16
  Speaker 2: I mean, it's not hard to imagine you find yourself
• 14:18
  Speaker 2: inside a catgut with somebody else that's a dot. One
• 14:21
  Speaker 2: thing leads to another.
• 14:24
  Speaker 1: So this is a kind of parasite that's called trophically transmitted,
• 14:26
  Speaker 1: which means a host that's infected gets eaten by a predator,
• 14:29
  Speaker 1: and that's how the parasite makes it to the next host.
• 14:32
  Speaker 1: And in different systems, like in trematodes and nematodes and tapeworms,
• 14:36
  Speaker 1: like lots of different kinds of parasites have this system,
• 14:40
  Speaker 1: and there's usually one species out of all of them
• 14:42
  Speaker 1: in there where sexual reproduction happens, and then in the
• 14:45
  Speaker 1: other hosts they just kind of replicate asexually. And to
• 14:48
  Speaker 1: be honest, I don't know why they're not able to
• 14:51
  Speaker 1: flexibly reproduce sexually in all of those hosts. Maybe I'll
• 14:56
  Speaker 1: look that up and we'll do a different show on it.
• 14:57
  Speaker 1: I don't know why it's just cats. It seems like
• 14:59
  Speaker 1: it would be to be able to do it everywhere.
• 15:01
  Speaker 1: But the other thing about these cats is after they
• 15:04
  Speaker 1: reproduce sexually, they produce a stage called oocysts, which I'm
• 15:07
  Speaker 1: just going to call eggs for the rest of the
• 15:10
  Speaker 1: conversation because it just makes it easier.
• 15:12
  Speaker 2: Please do I didn't want to pronounce that word.
• 15:14
  Speaker 1: Yeah, maybe I'm saying it wrong. Who cares. But they
• 15:16
  Speaker 1: get pooped out into the environment when the cat poops,
• 15:19
  Speaker 1: and that's how the parasite gets back out into the
• 15:21
  Speaker 1: environment to infect a bunch of other organisms.
• 15:23
  Speaker 2: So don't eat cat poop is the lesson here.
• 15:26
  Speaker 1: Well, it's not that simple, right, because cat poop looks
• 15:28
  Speaker 1: like cat poop at first, right, that's pretty obvious. But
• 15:31
  Speaker 1: over time, cat poop gets like worked into the soil
• 15:33
  Speaker 1: and you might not know there's cat poop, and these
• 15:36
  Speaker 1: eggs can stay in the environment for a really long time.
• 15:39
  Speaker 2: This episode is going to make me like cats less, Kelly.
• 15:41
  Speaker 1: Unfortunately, yes, it will outdoor cats in particular less. So
• 15:46
  Speaker 1: like if you have a garden and a outdoor cat
• 15:50
  Speaker 1: comes by and poops in your garden and you don't
• 15:52
  Speaker 1: realize it, and it gets mixed in with the soil,
• 15:54
  Speaker 1: then maybe one day you'll pull a vegetable not rinse
• 15:57
  Speaker 1: it sufficiently, and then you'll get infected. Or you'll be
• 16:00
  Speaker 1: gardening and you get the eggs on your hands and
• 16:02
  Speaker 1: you don't realize it. They're like microscopic, and then you
• 16:05
  Speaker 1: go to eat something else before washing your hands, and
• 16:07
  Speaker 1: you get infected. And this is also how like birds
• 16:10
  Speaker 1: and rodents and stuff like that get infected. Once you
• 16:13
  Speaker 1: get infected, they get ingested and then they move out
• 16:16
  Speaker 1: into your muscles and into your brain.
• 16:18
  Speaker 2: What about the blood brain barrier I hear all about.
• 16:21
  Speaker 2: Isn't that my vaunted protection for my brain cell.
• 16:24
  Speaker 1: Matter doesn't work for this parasite. In fact, the parasite
• 16:26
  Speaker 1: goes into your neurons, and that's what makes it actually
• 16:29
  Speaker 1: impossible to get rid of once you're infected. If you're
• 16:32
  Speaker 1: get infected with this parasite, you're gonna have it.
• 16:34
  Speaker 2: Forever, forever. There's no way to get rid of it.
• 16:36
  Speaker 1: No, no, because we can't get medication like into your neurons.
• 16:39
  Speaker 2: Oh wow, Yeah, this thing is pretty clever and insidious.
• 16:42
  Speaker 2: I'm terrified now.
• 16:43
  Speaker 1: Most successful parasite on the planet.
• 16:45
  Speaker 2: This is appropriate for Halloween.
• 16:46
  Speaker 1: Yes, it's some spooky stuff. So when it first gets
• 16:51
  Speaker 1: in there, it starts copying and pasting itself like crazy,
• 16:54
  Speaker 1: and you feel kind of like you have the flu.
• 16:56
  Speaker 1: Some people feel worse than others, Like I have a
• 16:57
  Speaker 1: friend who found out he got infected by toxoplusmos by
• 17:00
  Speaker 1: bringing in two feral kittens into his house. And when
• 17:03
  Speaker 1: he was changing the litter box, he must not have
• 17:05
  Speaker 1: like washed his hands well enough, or maybe they like
• 17:07
  Speaker 1: you know, scratched around in the litter box and then
• 17:10
  Speaker 1: walked on the kitchen table or something like that. And
• 17:12
  Speaker 1: so he got infected. His lymph nodes swelled up, and
• 17:14
  Speaker 1: he called me and he was like, what's gonna happen
• 17:16
  Speaker 1: to me? Now?
• 17:18
  Speaker 2: You're a zombie. Forget it. That's why life is over.
• 17:23
  Speaker 1: So you feel kind of crummy for a while.
• 17:25
  Speaker 2: Wait, but how are these things reproducing in your brain?
• 17:28
  Speaker 2: Does that mean they're eating your neurons? Like where are
• 17:30
  Speaker 2: they getting raw materials and energy? Like what are they gobbling?
• 17:33
  Speaker 1: They are gobbling some nutrients. A lot of parasites at
• 17:37
  Speaker 1: this stage are pretty energy efficient, So if they were
• 17:41
  Speaker 1: to straight up kill a host while replicating in their brain,
• 17:45
  Speaker 1: they probably would not have matured to the stage where
• 17:47
  Speaker 1: they can survive transmitting to the next host. So often
• 17:51
  Speaker 1: there's like this stage in between when you first infect
• 17:54
  Speaker 1: a host and when you can survive if that host
• 17:57
  Speaker 1: gets eaten to live in the next host, and so
• 17:59
  Speaker 1: you usually parasites are like pretty careful about energy usage,
• 18:04
  Speaker 1: so they don't like totally kill the host or like
• 18:06
  Speaker 1: cause it to I don't know, fall off a bridge
• 18:08
  Speaker 1: or something. But so, yeah, they're being pretty energy efficient,
• 18:11
  Speaker 1: but they are replicating. You're feeling kind of grummy.
• 18:14
  Speaker 2: And they're active in your brain. Is this how they're
• 18:16
  Speaker 2: changing your behavior somehow?
• 18:17
  Speaker 1: We don't know, So it does seem like behavioral changes
• 18:20
  Speaker 1: have something to do with either changes in dopaminergic activity.
• 18:24
  Speaker 1: So dopamine is a neurotransmitter you have in your brain.
• 18:27
  Speaker 1: The parasite has genes for I think it's called tyrosine hydroxylase,
• 18:32
  Speaker 1: and that's the limiting factor in the production of dopamine.
• 18:35
  Speaker 1: So all the other stuff that you need to make
• 18:38
  Speaker 1: dopamine is present on the inside of a neuron, but
• 18:41
  Speaker 1: when you dump tirosine hydroxylase in there, the rest of
• 18:44
  Speaker 1: the reaction just happens and you get dopamine.
• 18:46
  Speaker 2: Isn't dopamine good? Don't you want dopamine? Dopamine makes you
• 18:48
  Speaker 2: feel good, right.
• 18:49
  Speaker 1: I mean, dopamine is good. It makes you feel good,
• 18:51
  Speaker 1: but it also controls a bunch of other sorts of behavior.
• 18:55
  Speaker 1: Presumably our brains are making something like the right amount,
• 18:58
  Speaker 1: and then the parasite is notching the us up, so
• 19:00
  Speaker 1: you're making more of it than you would have wanted.
• 19:03
  Speaker 2: Now I'm imagining happy zombies, all these people walking around
• 19:06
  Speaker 2: mind the grinning. Oh well, they're all infected. Look at them.
• 19:09
  Speaker 1: Life is better with tuxo.
• 19:13
  Speaker 2: If you meet somebody who's grumpy, you know they're not infected. See,
• 19:16
  Speaker 2: And that's the what to tell.
• 19:17
  Speaker 1: Yeah, And there have been some experiments where they've given
• 19:20
  Speaker 1: rodents drugs for people who have sort of dopaminergic imbalances
• 19:26
  Speaker 1: or imbalances of dopamine in their brain, and a lot
• 19:29
  Speaker 1: of the weird behaviors that the rodents do sort of
• 19:32
  Speaker 1: either get tamped down or go away. So it does
• 19:34
  Speaker 1: seem like dopamine has something to do with it. But
• 19:38
  Speaker 1: one of the things we've discovered in this field is
• 19:40
  Speaker 1: that nothing is ever straightforward, and I mean the field
• 19:42
  Speaker 1: of how parasites change the behavior of the creatures that
• 19:45
  Speaker 1: they infect, It almost always involves lots of different things.
• 19:49
  Speaker 1: And so there's also some evidence that it's just like
• 19:51
  Speaker 1: the whole brain has inflammation when the parasites are in there,
• 19:54
  Speaker 1: and it might be that generalized inflammation causes things. The
• 19:58
  Speaker 1: parasites might also be localizing in certain parts of the
• 20:01
  Speaker 1: brain and making behaviors weird. It might also have something
• 20:04
  Speaker 1: to do with argentine vasa pressin or something to do
• 20:06
  Speaker 1: with testosterone, So you might notice that in the outline
• 20:10
  Speaker 1: I hadn't put anything about mechanisms because it's just like
• 20:13
  Speaker 1: such a mess right now. There's a lot of different
• 20:15
  Speaker 1: things it could be.
• 20:16
  Speaker 2: So it's active in the brain. It probably changes brain chemistry.
• 20:20
  Speaker 2: We don't understand completely the mechanism for how it's doing that.
• 20:24
  Speaker 2: Are there behaviors though in people that we can identify
• 20:28
  Speaker 2: as due to this impact, even if we don't have
• 20:30
  Speaker 2: all these little pieces that connect the dots. Are there
• 20:33
  Speaker 2: characteristic ways that it changes people's behavior? Or is it
• 20:37
  Speaker 2: mostly in cats that we notice the change in behaviors?
• 20:40
  Speaker 1: So cats don't usually show behavioral changes, So the parasites
• 20:44
  Speaker 1: replicating in the gut, we haven't associated any behavioral changes
• 20:48
  Speaker 1: with that. Humans are interesting. So we're jumping ahead a
• 20:50
  Speaker 1: little and that's okay. But so usually what happens with
• 20:53
  Speaker 1: like a rodent that gets infected is you see some
• 20:55
  Speaker 1: behavioral changes, and then when the cat eats the muscles
• 20:58
  Speaker 1: of that rodent, the parasite gets back to the cat.
• 21:01
  Speaker 1: So usually manipulation is supposed to help with some transmission
• 21:05
  Speaker 1: goal for the parasite. So when you're in a rodent,
• 21:08
  Speaker 1: the goal is to get it eaten by a cat,
• 21:10
  Speaker 1: but with humans, we don't usually get eaten by cats.
• 21:14
  Speaker 2: Sometimes we do big cats.
• 21:16
  Speaker 1: Yeah, yeah, sometimes big cats, but like it's pretty rare
• 21:20
  Speaker 1: and so we are kind of a dead end from
• 21:23
  Speaker 1: the perspective of getting back to cats. There are some
• 21:26
  Speaker 1: other ways that we can pass it. For example, men
• 21:29
  Speaker 1: can pass it to women during intercourse. We think when
• 21:31
  Speaker 1: I think about that, I'm like, ah, I'm so glad
• 21:33
  Speaker 1: I'm not dating anymore anyway, sorry everyone. Moms can pass
• 21:38
  Speaker 1: it to their children. It's called trans placental, so it
• 21:41
  Speaker 1: goes from the mom to the baby. So if mom
• 21:43
  Speaker 1: gets infected for the first time ever when she's pregnant,
• 21:45
  Speaker 1: it can pass into the fetus. Or if mom gets
• 21:48
  Speaker 1: infected for the first time when she's breastfeeding, I can
• 21:51
  Speaker 1: do trans mammory transmission, which means it goes across the
• 21:54
  Speaker 1: memory lands during breastfeeding into the baby. It still has
• 21:57
  Speaker 1: some options to get from host to host, but we're
• 21:59
  Speaker 1: probably not back to cats. But it is associated with
• 22:03
  Speaker 1: behavioral changes in humans. In humans, right after that stage
• 22:06
  Speaker 1: where it's replicating like crazy, it kind of slows down.
• 22:09
  Speaker 1: It slows its replication. But there's still some evidence that
• 22:12
  Speaker 1: it changes human behaviors. And the interesting thing about like
• 22:15
  Speaker 1: the study of this is there's this guy named Yaroslav Flager.
• 22:19
  Speaker 1: He's a Czech scientist, and apparently he was like, you know,
• 22:24
  Speaker 1: I do a lot of behaviors that really aren't in
• 22:25
  Speaker 1: my own interest, and I just kind of do a
• 22:28
  Speaker 1: bunch of weird stuff. I wonder if that, like brain
• 22:31
  Speaker 1: infecting parasite is to blame. Always makes me wonder like
• 22:35
  Speaker 1: is he just looking for excuses for like, well, I'm
• 22:37
  Speaker 1: a jerk, but it's not my fault I'm infected by
• 22:40
  Speaker 1: this parasite.
• 22:41
  Speaker 2: All right, I want to hear a lot more about
• 22:43
  Speaker 2: Yaroslav and his zombie research and how he wrote zombies
• 22:47
  Speaker 2: into his proposals to get big money from science foundations.
• 22:50
  Speaker 2: But first we have to take a quick break. So
• 22:52
  Speaker 2: go clean up your cat litterbox to keep your family
• 22:55
  Speaker 2: safe and come right back. All right, we're back, and
• 23:14
  Speaker 2: we're talking about the science of Halloween, more specifically zombies.
• 23:18
  Speaker 2: What are they in biology? Are they really like zombie behaviors?
• 23:22
  Speaker 2: And is toxoplasma GANDHII All it's been cracked up to
• 23:25
  Speaker 2: be in the popular science literature. And you were telling
• 23:28
  Speaker 2: us about a guy who's been doing research into the
• 23:31
  Speaker 2: impact on humans of this little bug. Tell us what
• 23:35
  Speaker 2: he did and what he learned.
• 23:36
  Speaker 1: Well, so what he was doing was he would draw
• 23:38
  Speaker 1: blood from a group of people. And when you look
• 23:41
  Speaker 1: at people's blood, if you've been infected by this parasite,
• 23:44
  Speaker 1: which you'll have forever, your immune system mounts a response
• 23:48
  Speaker 1: to it, and you always will have that signature of
• 23:51
  Speaker 1: the immune system response in your blood Forevermore So, if
• 23:54
  Speaker 1: you draw blood, you can look at the blood and say, Okay,
• 23:57
  Speaker 1: this person was definitely infected by the parasite at some point.
• 24:00
  Speaker 1: You don't know when, but you know that at some
• 24:02
  Speaker 1: point they were infected, and the parasite is probably just
• 24:04
  Speaker 1: chilling out in the brain.
• 24:05
  Speaker 2: Now, okay, Because if you have it, you have it forever, right,
• 24:07
  Speaker 2: So you're infected at some point, you're still infected, that's right.
• 24:10
  Speaker 2: This is just a way to tell who's got it
• 24:12
  Speaker 2: and who doesn't have it.
• 24:13
  Speaker 1: Yep, right, So by drawing blood, you don't need to
• 24:15
  Speaker 1: like invasively dissect someone's brain to know if they've got it.
• 24:18
  Speaker 1: You can just draw blood, and that way you know
• 24:20
  Speaker 1: who's got it and who doesn't, and then you can
• 24:22
  Speaker 1: give people personality tests, and you can look for correlations
• 24:26
  Speaker 1: between the answers that they give on those personality tests
• 24:29
  Speaker 1: and their infection status. Does that make sense?
• 24:32
  Speaker 2: It does, But these correlational studies are really hard to interpret, right,
• 24:35
  Speaker 2: Like you might just be selecting for cat people versus
• 24:38
  Speaker 2: dog people, and there's a whole lot of potential confounding
• 24:41
  Speaker 2: variables there, right.
• 24:43
  Speaker 1: Amen, So we have reached the first of my main
• 24:46
  Speaker 1: problems with this field. It could be that there's some
• 24:49
  Speaker 1: third behavior that predisposes people to getting infected, and then
• 24:54
  Speaker 1: when you give them this personality test which you're really measuring,
• 24:57
  Speaker 1: is that they have this behavior to begin with, and
• 24:58
  Speaker 1: that's what got them infected necessarily that the parasite gave
• 25:01
  Speaker 1: them the behavior.
• 25:02
  Speaker 2: So what you really need is some good control where
• 25:05
  Speaker 2: you take a person, you clone them, then you infect them,
• 25:08
  Speaker 2: then you create a perfectly identical world for them to experience,
• 25:12
  Speaker 2: and then you see their changes in behavior. Why don't
• 25:14
  Speaker 2: people just do that experiment? Kelly? Biology is so easy, that.
• 25:17
  Speaker 1: Sounds so ethical, it does, But maybe that's why we
• 25:20
  Speaker 1: have it yet.
• 25:22
  Speaker 2: See, I just don't have those scientific bones. Because particles
• 25:26
  Speaker 2: don't have consent forms, they don't have rights. We annihilate
• 25:29
  Speaker 2: them all the time. No big deal. They don't have
• 25:31
  Speaker 2: a union.
• 25:32
  Speaker 1: It's great, no IRB committees. I'm jealous. I mean, there
• 25:35
  Speaker 1: are some ways to get at this, Like if you
• 25:37
  Speaker 1: do cohort studies where you follow individuals from the beginning
• 25:40
  Speaker 1: of their lives and you regularly measure their behavior and
• 25:43
  Speaker 1: you regularly measure their infection status, then maybe you can
• 25:46
  Speaker 1: start to disentangle what parasites changed after infection. And these
• 25:51
  Speaker 1: cohort studies are really expensive, really time consuming. But without
• 25:55
  Speaker 1: doing controlled infections, that's probably the best we can do.
• 25:58
  Speaker 1: But there's not a lot of studies that have done all.
• 26:00
  Speaker 2: Right, so we've qualified this already by saying we don't
• 26:03
  Speaker 2: know what we can learn from these studies. But tell
• 26:06
  Speaker 2: us what do the studies reveal?
• 26:07
  Speaker 1: Okay, So here is the stuff that's sort of exciting
• 26:10
  Speaker 1: to talk about over tea or over beer or something. Okay.
• 26:13
  Speaker 1: So people who are infected tend to seek novelty less,
• 26:16
  Speaker 1: so they're less likely to want to go out and
• 26:18
  Speaker 1: try new things. Don't know why. There's a lot of
• 26:21
  Speaker 1: sex specific differences. So women who are infected tend to
• 26:24
  Speaker 1: be less suspicious, and men who are infected tend to
• 26:27
  Speaker 1: be more suspicious.
• 26:29
  Speaker 2: And are men who are infected less likely to wear
• 26:31
  Speaker 2: Halloween costumes?
• 26:33
  Speaker 1: Oh, it depends on how novel those costumes are. You know,
• 26:37
  Speaker 1: if they're comfortable with it, maybe they're.
• 26:39
  Speaker 2: Fine, non novel, non suspicious costumes. That's your pitch to
• 26:43
  Speaker 2: zact next time.
• 26:44
  Speaker 1: Well, I don't know if he's infected or not. It's
• 26:45
  Speaker 1: hard to say. He does work in the garden a lot.
• 26:47
  Speaker 2: There you go. See, I'm starting to ask questions.
• 26:49
  Speaker 1: Here you should. And then women who are infected tend
• 26:54
  Speaker 1: to be more warm and like caring, and men tend
• 26:57
  Speaker 1: to be either less warm or unchanged by the parasite.
• 27:01
  Speaker 2: Interesting.
• 27:02
  Speaker 1: I get a lot of questions about like does this
• 27:04
  Speaker 1: parasite turn people into crazy cat ladies? But actually the
• 27:09
  Speaker 1: evidence is that women who are infected tend to think
• 27:12
  Speaker 1: cat urine smells less good. They're like, oh, this is
• 27:14
  Speaker 1: an unpleasant smell.
• 27:15
  Speaker 2: Cat Urine already smells zero good. How can you be
• 27:18
  Speaker 2: hit less good than zero?
• 27:20
  Speaker 1: See, there's various levels of repulsion, okay, and infected women
• 27:24
  Speaker 1: are more repulsed, but infected men relative to uninfected men,
• 27:29
  Speaker 1: rate the smell of cat urine as being more pleasant.
• 27:32
  Speaker 1: What so maybe crazy cat men. I don't know. There
• 27:37
  Speaker 1: are some quantifiable effects at the country level. Also, a
• 27:41
  Speaker 1: friend of mine looked at personality aggregate scores by countries
• 27:45
  Speaker 1: and also the percent of people in a country who
• 27:47
  Speaker 1: are infected, and we tend to have like pretty good
• 27:49
  Speaker 1: data on percents because often when women are pregnant, they'll
• 27:52
  Speaker 1: get a test to see if they have the parasite.
• 27:54
  Speaker 1: Because if you have the parasite already, your immune system
• 27:58
  Speaker 1: probably has it in check and it's not going to
• 28:00
  Speaker 1: transmit to your fetus. But if you get infected, well
• 28:03
  Speaker 1: you're pregnant, it can transmit. So if you are pregnant
• 28:06
  Speaker 1: and you're not already infected, then you're often told like,
• 28:09
  Speaker 1: don't change any litter boxes. Have your partner do that.
• 28:12
  Speaker 1: But anyway, so we've got these country level scores and
• 28:14
  Speaker 1: countries with more toxoplasma gandhi I tend to be more neurotic.
• 28:18
  Speaker 2: Which countries are more neurotic?
• 28:19
  Speaker 1: Come on, oh all right, let's look up Lafferty's paper
• 28:22
  Speaker 1: real quick.
• 28:25
  Speaker 2: I want to slander some nations here. I'm gonna guess
• 28:28
  Speaker 2: more Pacific, more tropical, more equatorial, is more laid back.
• 28:32
  Speaker 2: And more northern colder, it's going to be more neurotic.
• 28:35
  Speaker 2: That's going to be my totally uninformed Basian prior on
• 28:38
  Speaker 2: this one.
• 28:39
  Speaker 1: So this paper was some two thousand and six, so
• 28:41
  Speaker 1: it looks like Yugoslavia, according to this study, had sixty
• 28:46
  Speaker 1: seven percent prevalence, and then Hungary had fifty nine percent.
• 28:50
  Speaker 1: Brazil was it sixty seven percent. So those are some
• 28:54
  Speaker 1: of the top countries. That doesn't necessarily mean that the
• 28:57
  Speaker 1: most neurotic. It's like an association, there's some move along
• 29:00
  Speaker 1: that correlation line, but those are some of the more
• 29:02
  Speaker 1: neurotic countries, some of the countries with the higher prevalence
• 29:05
  Speaker 1: of the parasite countries with the lowest prevalence. I'm seeing
• 29:09
  Speaker 1: Finland is at like sixteen percent, so is Israel. Norway
• 29:15
  Speaker 1: is at nine percent. South Korea is only at four percent.
• 29:18
  Speaker 2: That's basically the opposite of what I predicted. I predicted
• 29:21
  Speaker 2: like Norway and Finland would be very neurotic and Brazil
• 29:23
  Speaker 2: would be very chill.
• 29:24
  Speaker 1: So why would nor would be very neurotic? They were
• 29:27
  Speaker 1: pretty laid back when I was there. They take weekends
• 29:29
  Speaker 1: off in Norway, they were serious about that. They take
• 29:32
  Speaker 1: August off Man.
• 29:33
  Speaker 2: Yeah, they are like the richest nation on earth because
• 29:35
  Speaker 2: of their oil wealth, so maybe that helps. Maybe their
• 29:38
  Speaker 2: toxoplasma GANDHII infected them and told them where the oil
• 29:41
  Speaker 2: was going to be. Oh wait, no, you're saying they're
• 29:43
  Speaker 2: less infected, they're more infected. I'm confused.
• 29:45
  Speaker 1: They're less infected, so probably statistically they would be expected
• 29:50
  Speaker 1: to be less neurotic.
• 29:51
  Speaker 2: All right, So most of the zombies on Earth you're
• 29:53
  Speaker 2: saying are in Brazil, Hungary and the former Yugoslavia.
• 29:57
  Speaker 1: Yes, that's probably the right conclusion.
• 30:00
  Speaker 2: And maybe apology to all of our listeners in those countries.
• 30:04
  Speaker 1: That's right. So there's also a bunch of other correlations.
• 30:07
  Speaker 1: We probably don't want to spend too long on this
• 30:09
  Speaker 1: because I'd also like to get to the rodents real
• 30:11
  Speaker 1: quick and still leave you some time to talk about ghosts.
• 30:13
  Speaker 1: But there are some worrying things. There's like association with suicides,
• 30:17
  Speaker 1: association with schizophrenia, association with being more likely to be
• 30:21
  Speaker 1: in a traffic accident, which we think is maybe because
• 30:24
  Speaker 1: of a bit of a delay in reaction times. So
• 30:27
  Speaker 1: it's not like they're driving from one side of the
• 30:29
  Speaker 1: road to another like crazy people. Acting like they're drunk.
• 30:32
  Speaker 1: It's just that if they're in a moment where they
• 30:33
  Speaker 1: need to make a split decision, they're a little slower
• 30:35
  Speaker 1: to respond. And we don't know for sure that that's
• 30:38
  Speaker 1: what it is, but that's one of the working hypotheses
• 30:40
  Speaker 1: right now.
• 30:40
  Speaker 2: All right, So we see these correlations between infection and behavior.
• 30:44
  Speaker 2: We don't know the calls of mechanism. We don't really
• 30:46
  Speaker 2: understand how it works from like a micro biochemical point
• 30:50
  Speaker 2: of view. Do we understand things better in other creatures
• 30:53
  Speaker 2: where we can actually do experiments like cats and rodents
• 30:56
  Speaker 2: that life cycle, like, does it change the behavior of
• 30:58
  Speaker 2: cats and rodents in some way that benefits the parasite?
• 31:02
  Speaker 1: Well, for both humans and rodents, there are studies that
• 31:06
  Speaker 1: don't always say the same thing. So you collect to
• 31:08
  Speaker 1: the same data in two different studies and sometimes you
• 31:10
  Speaker 1: find an effect and sometimes you don't. That's complicating.
• 31:12
  Speaker 2: Science is hard.
• 31:13
  Speaker 1: Science is so hard. But at least with rodents you
• 31:16
  Speaker 1: can do the controlled infections that you can't do in humans,
• 31:19
  Speaker 1: so you can look at how behavior changes following infection.
• 31:22
  Speaker 1: And one of the most exciting things about rodents studies
• 31:25
  Speaker 1: is this thing that's become called fatal feline attraction.
• 31:29
  Speaker 2: I want to see that movie. That sounds great.
• 31:31
  Speaker 1: It is, Yeah, it's such an interesting idea. So the
• 31:33
  Speaker 1: idea is that rodents, when they're not infected, they smell
• 31:37
  Speaker 1: cat urine, they freak out. They avoid the area because
• 31:39
  Speaker 1: that's the smell of a predator. They don't want to
• 31:41
  Speaker 1: get eaten. So if they can smell that a cat
• 31:43
  Speaker 1: has been around, they don't want to be in that area.
• 31:46
  Speaker 1: Makes sense, whereas rodents that are infected tend to spend
• 31:51
  Speaker 1: more time in those areas, almost as though they're attracted
• 31:54
  Speaker 1: to those areas. And there were some studies done that
• 31:57
  Speaker 1: show that, like you know, when you have an uninfected rodent,
• 31:59
  Speaker 1: the part their brain associated with fear kind of lights
• 32:02
  Speaker 1: up when they smell cat urine, But when you have
• 32:05
  Speaker 1: infected animals, the part of their brain associated with getting
• 32:09
  Speaker 1: excited about a potential partner lights up. So it's almost
• 32:12
  Speaker 1: like the parasite is changing this response to this chemical
• 32:16
  Speaker 1: cue from absolutely petrifying to like something that's maybe kind
• 32:20
  Speaker 1: of sexy. But two problems here. One, you don't always
• 32:26
  Speaker 1: see this effect. Sometimes you do the controlled infections and
• 32:29
  Speaker 1: you don't see this attraction to the smell of cat urine,
• 32:32
  Speaker 1: and it looks like maybe it differs depending on like,
• 32:34
  Speaker 1: are you using an inbred rodent strain that's been living
• 32:37
  Speaker 1: in the lab for a really long time. Are you
• 32:39
  Speaker 1: looking at males or females? How long has the rodent
• 32:42
  Speaker 1: been infected? What strain of Toxoplasma gandhi are you using?
• 32:47
  Speaker 1: And so if you read the popular literature, they're like, oh, man,
• 32:50
  Speaker 1: rodents who are infected, they're attracted to cat urine. But
• 32:54
  Speaker 1: at the end of the day, the answer is much
• 32:55
  Speaker 1: more complicated. Sometimes we see the effects, sometimes we don't.
• 32:58
  Speaker 1: At the moment, we don't really understand why.
• 33:00
  Speaker 2: And even if the story we're true, the explanation would
• 33:03
  Speaker 2: be that the parasite wants the rat to get eaten
• 33:06
  Speaker 2: by a cat because it wants to get back into
• 33:09
  Speaker 2: the cat's gut for more reproductive.
• 33:11
  Speaker 1: Sexy time exactly. And then here's another problem. So I
• 33:15
  Speaker 1: was talking to one of the people who did the
• 33:17
  Speaker 1: original fatal feline attraction study, and I asked, when are
• 33:21
  Speaker 1: we going to see a study where rodents get infected,
• 33:25
  Speaker 1: we confirm that they're now more attracted to the smell
• 33:27
  Speaker 1: of cat urine, and then we release them into an
• 33:30
  Speaker 1: environment with cats and we see if that actually gets
• 33:33
  Speaker 1: them eaten, because right now we've got this story that
• 33:35
  Speaker 1: sounds super convincing, but we haven't actually shown it gets
• 33:37
  Speaker 1: them eaten. And her response was like, look, I would
• 33:41
  Speaker 1: never feel comfortable doing that to rodents. That's mean to
• 33:44
  Speaker 1: the rodents. We don't want to be infecting cats. I
• 33:47
  Speaker 1: don't want to have anything to do with that study.
• 33:50
  Speaker 1: And I think it would be hard to get past
• 33:51
  Speaker 1: an institutional Animal Care and Use Committee, which is the
• 33:55
  Speaker 1: organization that has to approve all of the experiments that
• 33:57
  Speaker 1: people at universities do. And so we don't actually have
• 34:01
  Speaker 1: that study. We don't actually have that connection. And you
• 34:04
  Speaker 1: can imagine that, you know, rodents who spend a lot
• 34:07
  Speaker 1: of time really examining an area where there's a cue
• 34:10
  Speaker 1: about a predator get a really good sense for like, Okay,
• 34:13
  Speaker 1: here's where the predator seems to go. Here are the
• 34:15
  Speaker 1: hiding places in the area. Maybe they're just like really
• 34:19
  Speaker 1: understanding the area, and when a cat shows up, they
• 34:22
  Speaker 1: know how to get out of there better then another
• 34:24
  Speaker 1: rodent who happens to be passing through. And I don't know,
• 34:26
  Speaker 1: I'm just making up stories now too, but The point
• 34:27
  Speaker 1: is we're all just making up stories.
• 34:29
  Speaker 2: The point is you're saying it's not so simple as
• 34:32
  Speaker 2: just rats who are attracted to cat here and get
• 34:34
  Speaker 2: eaten more. You're saying you could plausibly come up with
• 34:37
  Speaker 2: a scenario where it actually prevents them from getting eaten more,
• 34:40
  Speaker 2: and we actually need to go out and measure this
• 34:42
  Speaker 2: in the world. I think that's a huge lesson, right,
• 34:44
  Speaker 2: Like we're always attracted to these simple stories and science
• 34:47
  Speaker 2: and all of our science are stories. But just because
• 34:50
  Speaker 2: the story makes sense to us, doesn't mean it's the
• 34:52
  Speaker 2: way the world works. Right. We have to always go
• 34:54
  Speaker 2: out and do experiments and make measurements because the universe
• 34:57
  Speaker 2: is filled with surprises. Usually it's the kind of stuff
• 35:01
  Speaker 2: we're so certain about that turns out to be wrong.
• 35:03
  Speaker 1: And there have been some examples where we had this
• 35:05
  Speaker 1: great story and we thought it made sense, and then
• 35:07
  Speaker 1: when we did dig in a little bit more, it
• 35:09
  Speaker 1: fell apart. The behavior was not benefiting the parasite in
• 35:12
  Speaker 1: any way. So you do have to test these stories.
• 35:14
  Speaker 1: And I just want to tell you about one more
• 35:16
  Speaker 1: study that I think is the closest we've gotten so
• 35:19
  Speaker 1: far to trying to provide support for this, and this
• 35:22
  Speaker 1: is an indirect study that was done in Switzerland. So essentially,
• 35:25
  Speaker 1: there was this survey where people were asked like, okay,
• 35:28
  Speaker 1: when your cat catches something and they bring it home
• 35:30
  Speaker 1: to you, and they like, put it on your doorstep,
• 35:32
  Speaker 1: put it in a plastic bag, and bring it to us.
• 35:35
  Speaker 1: So they got this big collection of rodents that had
• 35:38
  Speaker 1: been killed by cats, and then they took blood from
• 35:42
  Speaker 1: all of these rodents and they looked to see what
• 35:44
  Speaker 1: percent of them were infected by the parasite, Okay, and
• 35:47
  Speaker 1: what they found was that for European water bowls, eleven
• 35:51
  Speaker 1: percent of them were infected by the parasite. So let's
• 35:54
  Speaker 1: walk through a really quick thought experiment to decide if
• 35:56
  Speaker 1: we're impressed by that or not. If one percent of
• 35:59
  Speaker 1: the poppylation of European water voles is infected and eleven
• 36:03
  Speaker 1: percent of the European water boles that are caught by
• 36:05
  Speaker 1: cats are infected, then that suggests that at least the
• 36:08
  Speaker 1: infected water bowls are selectively more likely to be killed
• 36:11
  Speaker 1: by cats. If eleven percent of the water bowls are
• 36:15
  Speaker 1: infected and eleven percent are being killed by cats, that's
• 36:18
  Speaker 1: just kind of random. You'd expect that from a random
• 36:20
  Speaker 1: draw of the population, So possibly the parasite isn't changing
• 36:23
  Speaker 1: behavior at all.
• 36:23
  Speaker 2: You're saying, if bowls are caught by cats more often
• 36:27
  Speaker 2: than their prevalence in the natural population, that suggests that
• 36:30
  Speaker 2: there's something making it easier for them to be.
• 36:32
  Speaker 1: Caught exactly, And that doesn't necessarily have to mean that
• 36:36
  Speaker 1: it's because the rodents are attracted to the smell of
• 36:38
  Speaker 1: cat urine. It could be because when you've got cysts
• 36:40
  Speaker 1: in your brain, you run into trees or something like that,
• 36:43
  Speaker 1: so totally different. But they looked at water voles in
• 36:47
  Speaker 1: another population and they put out traps and they found
• 36:50
  Speaker 1: that the percent of those water bowls that were infected
• 36:53
  Speaker 1: by the parasite was zero. So if you assume that
• 36:57
  Speaker 1: just about throughout all of Switzerland, most of the voles
• 37:00
  Speaker 1: are not infected by Toxoplasma gandhiy, but eleven percent of
• 37:03
  Speaker 1: them coming home in the mouth of a cat are,
• 37:07
  Speaker 1: then that does suggest that they're more likely than you
• 37:09
  Speaker 1: would expect to be getting caught by a cat after
• 37:14
  Speaker 1: they're infected.
• 37:15
  Speaker 2: So the cats are catching the ones that are infected
• 37:17
  Speaker 2: more than they're catching the ones that are not infected.
• 37:20
  Speaker 1: They're still bringing home more uninfected individuals because there's probably
• 37:25
  Speaker 1: still not loads of individuals who are infected by the
• 37:28
  Speaker 1: parasite in the environment. But of the population of les
• 37:32
  Speaker 1: that are out there, the ones that are infected are
• 37:33
  Speaker 1: more likely to get caught by cats than the ones
• 37:35
  Speaker 1: that are uninfected.
• 37:37
  Speaker 2: But these are water voles, like swimming around in lakes.
• 37:40
  Speaker 1: They don't spend all their time in the water. I
• 37:42
  Speaker 1: think they tend to be like associated with aquatic habitats.
• 37:45
  Speaker 2: I imagine like Brazilian voles, or like on the beach
• 37:47
  Speaker 2: all the time or something. I want to make a
• 37:49
  Speaker 2: connection to the human studies. But you know, that's just
• 37:52
  Speaker 2: me trying to tell a science story.
• 37:54
  Speaker 1: Yeah, I'm not sure that's supported by fact, but yeah, so,
• 37:57
  Speaker 1: I mean that's intriguing at least evidence. But I still
• 38:00
  Speaker 1: feel like that's not a slam dunk. So that's where
• 38:02
  Speaker 1: we are right now. We've got this cool story about zombies.
• 38:05
  Speaker 1: The evidence suggests that there's something happening. We know it's
• 38:08
  Speaker 1: in the brain that's enticing too, but we haven't really
• 38:11
  Speaker 1: locked up a bunch of loose ends that we have
• 38:13
  Speaker 1: to you know, slam dunk. Say this is definitely the
• 38:16
  Speaker 1: parasite manipulating rodent behavior to its own benefit. So there's
• 38:19
  Speaker 1: a lot of work left to do, all right.
• 38:21
  Speaker 2: So we know that this thing is out there, we
• 38:22
  Speaker 2: know it's infecting a lot of rats and other rodents.
• 38:25
  Speaker 2: We understand that it might be changing behavior, and it
• 38:28
  Speaker 2: might be changing the behavior of rudents in such a
• 38:30
  Speaker 2: way that gets them caught by cats more often, does
• 38:32
  Speaker 2: it also change the behavior of the cats or the
• 38:35
  Speaker 2: cats just the host for reproduction?
• 38:37
  Speaker 1: The cats are just the host for reproduction, and in general,
• 38:40
  Speaker 1: the hosts where the sexual reproduction is happening, we don't
• 38:43
  Speaker 1: often see a lot of behavior changes in those hosts.
• 38:46
  Speaker 1: We usually see behavioral changes in the hosts that need
• 38:49
  Speaker 1: to get eaten by those predators where the sexual reproduction
• 38:53
  Speaker 1: tends to happen.
• 38:54
  Speaker 2: And so tell me how this story then became so
• 38:57
  Speaker 2: prevalent in the popular media. There's a very simple story
• 39:00
  Speaker 2: about how this affects you and changes your behavior and
• 39:02
  Speaker 2: doctor thought you're a zombie. The science is much more
• 39:05
  Speaker 2: complicated and fuzzy, as it is always was there like
• 39:08
  Speaker 2: a seminal paper that overstated its claims, or like one
• 39:12
  Speaker 2: particular news coverage that misunderstood this or how did this
• 39:15
  Speaker 2: get centered in the popular mind is like the zombie parasite.
• 39:19
  Speaker 1: So there was a seminal paper. It was a Burdoi
• 39:22
  Speaker 1: at all two thousand, I think, and they were the
• 39:24
  Speaker 1: ones who identified fatal feline attraction. And it was a
• 39:29
  Speaker 1: good paper. The science was good. Sometimes you do find
• 39:32
  Speaker 1: this effect, sometimes you don't. They found it, and I
• 39:34
  Speaker 1: think that kind of blew up. And then Yaroslav Flager's
• 39:38
  Speaker 1: work suggesting that maybe it impacts human behavior too, came out,
• 39:41
  Speaker 1: and I think a bunch of people got excited. And
• 39:44
  Speaker 1: it could just be random chance that the first couple
• 39:46
  Speaker 1: papers that were looking for an effect hit on something,
• 39:50
  Speaker 1: and that's the story that made it out into the wild.
• 39:53
  Speaker 1: And in general, you know, the first study that finds
• 39:55
  Speaker 1: a cool effect is going to get a lot of press.
• 39:57
  Speaker 1: The second study that says they didn't find an effect
• 40:00
  Speaker 1: people don't usually want to talk about that. I did
• 40:02
  Speaker 1: work in another system that found that the effect of
• 40:05
  Speaker 1: a brain infecting parasite of fish on the fish's behavior
• 40:09
  Speaker 1: is like way less than we had previously thought. No
• 40:12
  Speaker 1: one cites my paper. They cite the first paper where
• 40:15
  Speaker 1: the effect was huge.
• 40:16
  Speaker 2: So even as a scientist. You're throwing cold water on theories,
• 40:19
  Speaker 2: not just in your popular science communication.
• 40:22
  Speaker 1: I didn't think this was going to be my niche.
• 40:24
  Speaker 1: I didn't want it to be my ditch. But yes,
• 40:26
  Speaker 1: that is the person that I am. So you know,
• 40:28
  Speaker 1: call me up and invite me to your parties if
• 40:30
  Speaker 1: you want to make sure they don't get too rowdy.
• 40:32
  Speaker 2: Well, you know, maybe the journalists that covered those papers
• 40:34
  Speaker 2: they were infected by the parasite, and the parasite influenced
• 40:38
  Speaker 2: them to write like hyperbolic statements about it because it
• 40:41
  Speaker 2: just wanted to be famous.
• 40:42
  Speaker 1: And that is the fun thing about talking about this system.
• 40:44
  Speaker 1: You always get new hypotheses and fun conversations. And yeah,
• 40:49
  Speaker 1: it's just exciting to think about. But you know what
• 40:51
  Speaker 1: else is exciting to think about?
• 40:52
  Speaker 2: What's that?
• 40:53
  Speaker 1: Ghosts? Oooooooo, it's as spooky as not having a enough dude.
• 41:03
  Speaker 1: Let's take a break and come back and talk about
• 41:05
  Speaker 1: the physics behind ghost busting. And we're back, and now
• 41:27
  Speaker 1: it's Daniel's turn to tackle ghosts. All right, Daniel, tell
• 41:32
  Speaker 1: me about the science behind ghost busting, and don't disappoint
• 41:35
  Speaker 1: me because when you first mentioned this topic, I'm like,
• 41:38
  Speaker 1: oh man, every once while you have a conversation with
• 41:40
  Speaker 1: someone and you're like, ah, I thought I understood you,
• 41:45
  Speaker 1: But you believe in ghosts, and that's fine, but that's
• 41:48
  Speaker 1: not what I would have predicted.
• 41:49
  Speaker 2: I've had that experience, I know, yeah, and I never
• 41:52
  Speaker 2: quite know how to approach that. I'm like, wow, okay,
• 41:55
  Speaker 2: how do you hold this in your mind? What is
• 41:57
  Speaker 2: it you believe or is this in some sort of
• 41:59
  Speaker 2: portion of your where you don't apply the same sort
• 42:01
  Speaker 2: of like rational careful thinking that I know you apply
• 42:04
  Speaker 2: in the rest of your life. I try to always
• 42:06
  Speaker 2: approach you sort of generally and carefully to keep the
• 42:08
  Speaker 2: lines of communication open.
• 42:09
  Speaker 1: Yes, you know, I usually just transition to my listening
• 42:13
  Speaker 1: face and I stop asking questions, and I'm like, I
• 42:16
  Speaker 1: am listening. There are some questions science can't tackle, and
• 42:19
  Speaker 1: I will just listen to you now. But okay, tell
• 42:22
  Speaker 1: me about how have people attempted to use scientific techniques
• 42:25
  Speaker 1: to answer questions about whether or not there's ghosts?
• 42:27
  Speaker 2: Mm hmm. Well, first of all, I want to applaud folks,
• 42:30
  Speaker 2: because while there's a lot of stories about ghosts out there,
• 42:33
  Speaker 2: there are people out there who are trying to sort
• 42:36
  Speaker 2: of nail this down from a scientific point of view,
• 42:38
  Speaker 2: just the same way like you can talk about esp
• 42:41
  Speaker 2: and you know, pircognition and whatever, and the right thing
• 42:44
  Speaker 2: to do there is to do experiments like can people
• 42:46
  Speaker 2: predict what card you're holding in your hand? Can people
• 42:49
  Speaker 2: predict the future? Like, as we were saying earlier, you
• 42:52
  Speaker 2: got to keep an open mind because the universe is
• 42:54
  Speaker 2: crazy and it will surprise you, and you can't hold
• 42:57
  Speaker 2: on to pre existing narratives. You've got to be open
• 42:59
  Speaker 2: to it. But the way to learn about the universe
• 43:02
  Speaker 2: is not to just tell crazy stories that some parasite
• 43:04
  Speaker 2: in your brain is telling you, but to go out
• 43:06
  Speaker 2: there and do experiments. So while there's a lot of
• 43:09
  Speaker 2: like spooky silliness out there about ghosts, there are also
• 43:11
  Speaker 2: folks out there who try to see is there something
• 43:14
  Speaker 2: we can detect scientifically? Are there sensors we can use
• 43:18
  Speaker 2: to discover the physics of ghosts? If they are real,
• 43:20
  Speaker 2: If they're out there, you know, that means they're part
• 43:23
  Speaker 2: of the universe, which means they're physical, which means we
• 43:25
  Speaker 2: should be able to detect them. And predominantly from my
• 43:27
  Speaker 2: research by watching ghost hunting television shows, which I did
• 43:31
  Speaker 2: for this podcast, people use basically electromagnetic field meters, Like
• 43:36
  Speaker 2: they have these EMF meters that measure electromagnetic radiation, So
• 43:41
  Speaker 2: you can use this if you're curious, like how much
• 43:44
  Speaker 2: cell signal am I getting my house or whatever. Electromagnetic
• 43:47
  Speaker 2: Radiation is just like a kind of light. You know,
• 43:49
  Speaker 2: light is a wiggle in the electromagnetic field. Light is
• 43:52
  Speaker 2: electromagnetic radiation. It's a very broad spectrum, all the way
• 43:56
  Speaker 2: from radio waves with very long frequency up to extra
• 44:00
  Speaker 2: rays and gamma rays. This are not weird and spooky
• 44:03
  Speaker 2: in any way, Like we know what electromagnetic radiation is,
• 44:06
  Speaker 2: but there's the thought that maybe ghosts create electromagnetic radiation
• 44:11
  Speaker 2: or are themselves ripples in the electromagnetic field, because you know,
• 44:15
  Speaker 2: the electromagnetic field is important to life. You and I
• 44:18
  Speaker 2: both have a lot of electrochemistry going on, and so
• 44:21
  Speaker 2: that's one way people try to like use science to
• 44:24
  Speaker 2: see is there anything actually out there going on?
• 44:27
  Speaker 1: Is there an explanation for why we think that the
• 44:30
  Speaker 1: electromagnetic field, which we know living organisms give off, why
• 44:35
  Speaker 1: would we expect the dead to also be doing that?
• 44:38
  Speaker 1: Like why is that the thing that we're looking for?
• 44:40
  Speaker 2: M hm, I don't have an answer, But I do
• 44:43
  Speaker 2: have a hypothesis. Okay, First of all, we don't know
• 44:45
  Speaker 2: what ghosts are, right, So in order to predict that
• 44:47
  Speaker 2: they're making some physical impact, you have to have a
• 44:49
  Speaker 2: physical model. You say, ghosts are this or ghost are
• 44:51
  Speaker 2: that here? You have to sort of work backwards and
• 44:53
  Speaker 2: try to say, well, if how could ghosts create this
• 44:56
  Speaker 2: kind of signal? And I don't have an answer for you.
• 44:59
  Speaker 2: It's true that the doctromagnetic field is capable of carrying information,
• 45:03
  Speaker 2: and that information is massless, right, photons have no mass,
• 45:07
  Speaker 2: And so imagine like I took Kelly, and I broke
• 45:10
  Speaker 2: her down into her constituent bits and extracted all the
• 45:13
  Speaker 2: useful Kelly information, the pieces that made Kelly Kelly, and
• 45:17
  Speaker 2: not like the details of your toenails, but just like
• 45:20
  Speaker 2: your mind and your thoughts. You can imagine making that
• 45:22
  Speaker 2: digital the way people imagine you could like upload your
• 45:25
  Speaker 2: consciousness into a computer and you could encode that in photons.
• 45:30
  Speaker 2: So you know, I could take Kelly, tear you apart
• 45:32
  Speaker 2: into your information, convert you into photons, beam you through space.
• 45:36
  Speaker 2: Would that be ghost Kelly? I don't know. Maybe could
• 45:40
  Speaker 2: somehow you know people's thoughts and ideas which we don't
• 45:44
  Speaker 2: fully understand, of course, be transmitted into the electromagnetic field.
• 45:48
  Speaker 2: I don't know that's sort of the direction people are going.
• 45:51
  Speaker 2: I think what's really happening here is that people are
• 45:53
  Speaker 2: trying to be creative about ways we could identify ghosts,
• 45:56
  Speaker 2: and they're looking for the sensors we have at hand.
• 45:59
  Speaker 2: And it's easy to get an EMF meter, like they're cheap,
• 46:02
  Speaker 2: they're reactive. And here's my hypothesis is that old houses
• 46:08
  Speaker 2: have bad wiring, and when you're in an old spooky house,
• 46:12
  Speaker 2: you're gonna measure em fields or fluctuations in the electricity
• 46:16
  Speaker 2: and you're gonna go, oh my god, look we just
• 46:18
  Speaker 2: saw something. I have no data to support this, but
• 46:23
  Speaker 2: that's my hunch.
• 46:25
  Speaker 1: If someone said, Okay, Daniel, we're giving your lab five
• 46:29
  Speaker 1: million dollars to do the best study you can think
• 46:32
  Speaker 1: of to look for the existence of ghosts, what would
• 46:35
  Speaker 1: you measure or who the heck knows?
• 46:39
  Speaker 2: That's a great question which I'm shockingly unprepared for. I
• 46:44
  Speaker 2: think if you gave me that money, I would try
• 46:47
  Speaker 2: to find some location where people are reporting sort of
• 46:50
  Speaker 2: paranormal activity that we couldn't explain and then take as
• 46:53
  Speaker 2: broad data as we could so yeah, including ef meters
• 46:57
  Speaker 2: and other kinds of things, to see if we can
• 46:59
  Speaker 2: make some coral between the data we're collecting and people's experience,
• 47:04
  Speaker 2: and that way we could start to get a handle
• 47:05
  Speaker 2: on the physical phenomena. If there are indeed any that
• 47:08
  Speaker 2: are connected to people's personal experience. I don't know. We
• 47:12
  Speaker 2: do know that there's some connections between electromagnetic fields and
• 47:15
  Speaker 2: people's experience. You know, there are these crazy studies where
• 47:20
  Speaker 2: a psychologist created what he called the God helmet, where
• 47:25
  Speaker 2: he created his helmet and he put very strong electromagnetic
• 47:28
  Speaker 2: field emitting coils in the helmet and he put this
• 47:31
  Speaker 2: on people and he turns it on. So basically he
• 47:33
  Speaker 2: immersed your brain in a strong electromagnetic field. And he
• 47:37
  Speaker 2: reported that once the helmet was activated, the wearer's temporal
• 47:40
  Speaker 2: lobes their brain were pounded with these fields, and eighty
• 47:44
  Speaker 2: percent of the people who wore this helmet reported feeling
• 47:47
  Speaker 2: quote a presence of some kind in the room with them,
• 47:49
  Speaker 2: including on some occasions visions of God. So you know,
• 47:54
  Speaker 2: we know the brain is made of neurons, and neurons
• 47:57
  Speaker 2: are electromagnetic. They send little pulses of signals, and so
• 48:00
  Speaker 2: it's not crazy to imagine that if your brain is
• 48:03
  Speaker 2: immersed in a strong field, it might change the way
• 48:05
  Speaker 2: that it behaves. So now we're talking physics zombies, right,
• 48:10
  Speaker 2: and it changes the way people feel, what they experience
• 48:12
  Speaker 2: and what they see. So it could be that if
• 48:15
  Speaker 2: you're in a crazy old house with strong electromagnetic fields,
• 48:18
  Speaker 2: those things change the way your brain behaves. Plus you're
• 48:22
  Speaker 2: expecting to see something sort of weird. There's a lot
• 48:25
  Speaker 2: of psychology and physics going on here, So it could
• 48:27
  Speaker 2: be that that's a physical phenomena that could connect people's
• 48:30
  Speaker 2: experience and like readings on an EMF meter.
• 48:33
  Speaker 1: And so I assume that this guy set out to
• 48:36
  Speaker 1: disprove that there are ghosts and just showing that you
• 48:40
  Speaker 1: can create this with EMFs, not to show that EMFs
• 48:43
  Speaker 1: are the way that we communicate with the undead.
• 48:45
  Speaker 2: Right, Yeah, exactly. I don't think he was saying that
• 48:47
  Speaker 2: God is electromagnetic. No, he was saying that our perception
• 48:51
  Speaker 2: of reality is influenced by electromagnetic fields in a way
• 48:55
  Speaker 2: that it could make you feel like spooky or haunted.
• 48:58
  Speaker 2: And so you see a lot of EMF meters on
• 49:01
  Speaker 2: TV with ghost hunters, and I'll say that this is
• 49:04
  Speaker 2: TV show called the ghost Hunters, and they're always showing
• 49:06
  Speaker 2: up at these spooky houses looking and they never see anything.
• 49:10
  Speaker 2: There's never any readings on the meters that are useful
• 49:13
  Speaker 2: or interesting or conclusive, you know, which is probably why
• 49:15
  Speaker 2: the show keeps going because if they found ghosts, they
• 49:18
  Speaker 2: would be done, Oh yeah, we found it, show over,
• 49:20
  Speaker 2: so it would ruin the drama.
• 49:22
  Speaker 1: So I think in those shows they also say something like, oh,
• 49:25
  Speaker 1: the temperature drops suddenly, what do we know about that?
• 49:29
  Speaker 2: Yeah. Another popular technique is just like gathered data about
• 49:32
  Speaker 2: the temperature. So there are these meters you can buy.
• 49:35
  Speaker 2: They're called kestrel meters. Again, they're cheap, they're effective, so
• 49:38
  Speaker 2: a lot of people have them, and they can do
• 49:40
  Speaker 2: things like detect change in airflow or temperature or barometric pressure.
• 49:44
  Speaker 2: They're very useful for understanding weather and like it's a
• 49:46
  Speaker 2: tornado coming. And some ghost hunters believe that like a
• 49:49
  Speaker 2: sudden drop in temperature is a sign of paranormal activity.
• 49:53
  Speaker 2: There's no actual data to support that. Nobody's actually found
• 49:56
  Speaker 2: a correlation between people's reports of paranormal activity and temperature dropping.
• 50:01
  Speaker 2: But you know, it's another thing we can detect about
• 50:03
  Speaker 2: our environment, and it's the kind of study I totally support, Like,
• 50:07
  Speaker 2: let's keep an up in mind, let's go out there,
• 50:08
  Speaker 2: let's take physical data rather than just say I saw
• 50:12
  Speaker 2: a ghost in the corner. Yeah, because even if people
• 50:15
  Speaker 2: believe stuff, eyewitness reports are very very hard to use
• 50:18
  Speaker 2: scientifically because, as we know, they're influenced by memory and
• 50:22
  Speaker 2: emotion and all sorts of stuff.
• 50:23
  Speaker 1: Okay, So I have been dying for us to get
• 50:26
  Speaker 1: to the point where we get to talk about Ghostbusters
• 50:28
  Speaker 1: because when I was a kid, I was obsessed with Ghostbusters.
• 50:31
  Speaker 1: It's possible that my first crush was on Egon Nice,
• 50:36
  Speaker 1: the character in the cartoon. So how good is the
• 50:41
  Speaker 1: science there. They've got those proton packs, they can like
• 50:44
  Speaker 1: catch them in that box and store them in that container.
• 50:47
  Speaker 1: What is the science there?
• 50:50
  Speaker 2: Yees? So I love Ghostbusters and it's not hard science fiction,
• 50:54
  Speaker 2: but I do like that they dress it up a
• 50:56
  Speaker 2: little bit sciencey, you know, and the scientists are kind
• 50:59
  Speaker 2: of heroes in that story. They're creating technology, they're understanding it.
• 51:03
  Speaker 2: They're not just running around.
• 51:04
  Speaker 1: And being woo woo very handsome too.
• 51:06
  Speaker 2: Yeah, exactly, they're good looking, they're charismatic. So what's going
• 51:10
  Speaker 2: on with the science Ghostbusters? While they have these PKE meters,
• 51:14
  Speaker 2: you know, which detect psychic activity. pKa stands for psychokinetic energy,
• 51:19
  Speaker 2: and I think this is just like a fancy version
• 51:21
  Speaker 2: of an EMF meter. They invent this device, they don't
• 51:24
  Speaker 2: go into the details, like what exactly is it measuring?
• 51:27
  Speaker 2: How is it detecting psychic energy? I think it's basically
• 51:30
  Speaker 2: inspired by real life EMF meters like measure fluctuations in
• 51:34
  Speaker 2: the electromagnetic field.
• 51:35
  Speaker 1: So there is no actual such thing as a pKa meter.
• 51:38
  Speaker 2: No, it's just a prop you know, it doesn't actually
• 51:41
  Speaker 2: do anything. There is no psychic kinetic energy as a
• 51:44
  Speaker 2: physical concept. That would be awesome. Wow, somebody could invent
• 51:48
  Speaker 2: that that detected this new field of energy, like huge,
• 51:51
  Speaker 2: huge discovery about the nature of the universe.
• 51:54
  Speaker 1: That would be incredible.
• 51:56
  Speaker 2: But my favorite part about Ghostbuster science are the proton packs.
• 52:00
  Speaker 1: Well, all right, but clearly those would work, right.
• 52:02
  Speaker 2: Those would work in some sense, Like what is a
• 52:05
  Speaker 2: proton pack? If you look at the picture on their backs,
• 52:08
  Speaker 2: they have these circles on them, and what they're really
• 52:10
  Speaker 2: doing there is they're creating a little particle accelerator. Like
• 52:13
  Speaker 2: what do we do with the Large had Drunk Collider.
• 52:15
  Speaker 2: We take protons, we speed them up, We bend them
• 52:17
  Speaker 2: around in a circle so we can keep speeding them
• 52:19
  Speaker 2: up many many times, and then we smash them into stuff.
• 52:22
  Speaker 2: That's what a proton pack is. Takes protons, it spins
• 52:25
  Speaker 2: them around, it shoots them out. It's basically a proton
• 52:28
  Speaker 2: beam generator. And the science of that is pretty solid.
• 52:31
  Speaker 2: Like we build those things, we have those things in
• 52:33
  Speaker 2: real life. I have some comments about like the size
• 52:35
  Speaker 2: of those things on their backs, but like those are details.
• 52:38
  Speaker 1: Do you think one day we could shrink them down
• 52:40
  Speaker 1: enough that you could actually fit them on your back.
• 52:42
  Speaker 2: You could definitely have a proton pack small enough to
• 52:44
  Speaker 2: put on your back. The question is could it have
• 52:47
  Speaker 2: enough energy. The reason the Large had Drunk Collider is
• 52:49
  Speaker 2: so large is that when protons are going really really
• 52:52
  Speaker 2: fast and they have so much energy, it gets harder
• 52:54
  Speaker 2: to bend them. So you need super powerful magnets. At
• 52:57
  Speaker 2: the Large had Drunk Collider, we have like amazing souper
• 53:00
  Speaker 2: conducting magnets that are really awesome, and they can just
• 53:02
  Speaker 2: barely bend those protons around in a circle that's like
• 53:05
  Speaker 2: thirty three kilometers, So to get them within like half
• 53:09
  Speaker 2: a meter at very very high energy would require incredible magnets,
• 53:13
  Speaker 2: which would also be pretty dangerous, like you'd be walking
• 53:15
  Speaker 2: through the streets in New York and like everybody's keys
• 53:17
  Speaker 2: would be flying out of their pockets and like killing people.
• 53:21
  Speaker 2: So very small would require very high magnets. So that
• 53:24
  Speaker 2: part I'm a little skeptical of. The real question is
• 53:27
  Speaker 2: could you use a proton beam to somehow capture ghosts?
• 53:32
  Speaker 1: Okay, so how would that work? What would that have
• 53:34
  Speaker 1: to say about the ghosts in order for this to
• 53:35
  Speaker 1: all work out?
• 53:36
  Speaker 2: Yeah, exactly, Well, protons are positive, so you're shooting a
• 53:39
  Speaker 2: beam of positive charges and you're somehow hemming the ghosts
• 53:42
  Speaker 2: in with that. I mean, in the show, the beam
• 53:45
  Speaker 2: doesn't move perfectly straight. It's sort of like a whip,
• 53:48
  Speaker 2: more like Wonder Woman's lasso or something, which is definitely
• 53:51
  Speaker 2: not scientific, like the protons would move in a straight
• 53:53
  Speaker 2: line or be bent by a magnet. But I guess
• 53:56
  Speaker 2: if ghosts were like negatively charged, you know, some know,
• 54:00
  Speaker 2: then they would get attracted to the beam and you
• 54:03
  Speaker 2: could like stick the beam to them and even pull
• 54:05
  Speaker 2: them around with the beam. So yeah, if ghosts are
• 54:08
  Speaker 2: for some reason negatively charged, then protons are the right
• 54:11
  Speaker 2: way to hem them in.
• 54:13
  Speaker 1: So next year at this time, we'll be reviewing the
• 54:15
  Speaker 1: science about whether or not ghosts or negatively charged, because
• 54:18
  Speaker 1: people will probably follow up on your work here.
• 54:21
  Speaker 2: Well, if ghosts were positively charged, you could just use
• 54:23
  Speaker 2: an electron beam to capture them, but then you got
• 54:25
  Speaker 2: to know the charge of the ghost before you shoot
• 54:27
  Speaker 2: the beam at them, right, So you could do it
• 54:29
  Speaker 2: either way positive or negative, and new restriction there.
• 54:32
  Speaker 1: Gets very complicated, So let us know if you have
• 54:35
  Speaker 1: any data on this question. But actually, Barry Rich wrote
• 54:37
  Speaker 1: a really great book where she interacted with the community
• 54:40
  Speaker 1: of people who ask questions about this kind of stuff,
• 54:42
  Speaker 1: and I highly recommend every book ever written by Mary Roach.
• 54:45
  Speaker 2: She's excellent.
• 54:46
  Speaker 1: Yeah, okay, everybody, Happy Halloween. We hope you have an
• 54:49
  Speaker 1: amazing spooky day, and if you want to send us
• 54:52
  Speaker 1: any questions or suggestions for future shows, drop us a
• 54:56
  Speaker 1: line at Questions at Daniel and Kelly dot org.
• 54:58
  Speaker 2: Happy Halloween, everyone, and this episode goes to show you
• 55:01
  Speaker 2: there's science in everything, in me and you and even
• 55:04
  Speaker 2: in Halloween.
• 55:06
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