SGU Episode 883

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SGU Episode 883
June 11th 2022
(brief caption for the episode icon)
SGU 882                      SGU 884
Skeptical Rogues
S: Steven Novella
B: Bob Novella
C: Cara Santa Maria
J: Jay Novella
E: Evan Bernstein
Quote of the Week
What I love about experts, the best of them anyway, is that they get to their humility early. They have to. It's part of who they are; it's necessary for what they're doing. They set out to get to the bottom of something that has no bottom, and so they're reminded constantly of what they don't know. They move through the world focused not on what they know, but on what they might find out.
Michael Lewis, American author
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Introduction, What are the Rogues watching?

Voice-over: You're listening to the Skeptics' Guide to the Universe, your escape to reality.

S: Hello and welcome to the Skeptics' Guide to the Universe. Today is Wednesday, June 8^th 2022, and this is your host, Steven Novella. Joining me this week are Bob Novella...

B: Hey, everybody!

S: Cara Santa Maria...

C: Howdy.

S: Jay Novella...

J: Hey guys.

S: ...and Evan Bernstein.

E: Good evening folks!

S: So guys what are you all watching on TV recently? Anything good?

B: There's so much on right now. I gotta say the thing that got me pretty much the most excited is The Offer which is the making behind the scenes all the drama that went into the creation of The Godfather. I mean if half of this stuff is true. It's like kind of like a docudrama. I mean it's definitely not a documentary but a lot of the stuff a lot of the stuff that's happening really happened. And it's just the acting is great, the writing is fantastic, the characters just love them. Can't wait for every episode. So if you liked the Godfather definitely check out The Offer what's it on is that on?

S: Paramount+ because it was produced by Paramount. That's how you remember.

E: That would make sense.

C: I'm watching a few things on HBO and Showtime. Like some comedies. I'm watching First Lady and I Love That for You and a couple like fun things. But I think the thing that I saw most recently that like had me gripped and I could not wait until it would come out each week was Under the Banner of Heaven.

S: Yeah I hear really good things about them.

C: Ugh it's so good. So that's based on, it's on Hulu, it's based on John Krakauer's book that came out I think in the early 2000s. Like quite a famous book. Got a lot of buzz. Made the Mormon church none too pleased.

B: Good.

C: And of course, yeah, for me personally having been raised Mormon it hits in all the right places and it's a very deep dive into the misogyny of the religion. It's the story basically of a detective and he's played by Andrew Garfield we love him, right? Do you guys love him? I love him.

B: Oh yeah.

C: He's so good in this role too. I don't know there's just something about like he plays a Mormon guy so well. But yeah it's a story of a detective who is investigating, actually a true crime, a murder that took place in Utah more than a couple now. We're old. And it parallels him sort of learning about the foundings of the Mormon church. And seeing inconsistencies and questioning the morality of it and really questioning his own faith. So it's this really cool parallel story where they've got pioneer town scenes and then they've got modern day scenes. And then it's also a murder story. It's like all the good things.

S: I just binged my way through the first two seasons of The Umbrella Academy.

B: Oh how was that? I've been meaning to see that.

S: You haven't seen that? You haven't seen that at all?

B: No no. It's been on my list.

S: Oh my god. It's awesome. It's one of the best written shows on television.

B: Really?

C: Is it a comic book show?

S: It's a comic book.

E: It's based on Gerard Ways comic. Gerard Way was the lead singer for My Chemical Romance.

S: Yeah dark horse comics.

B: Oh man.

S: So it has good source material but just this the script writing is so tight and it does that thing where it anticipates like questions the audience might have and it deals with them, you know what I mean? Like everything has a is foreshadowed or explained somehow. It ties back together without necessarily hitting you over the head with it. Just so that the characters are are all wonderful. So the third season's coming out June 22^nd so I re-watched the first two seasons to remind myself of everything that happened. It's a good thing that I did because you forget so much. There's so much detail in there. But just so enjoyable. If you haven't seen it I highly recommend it.

J: Well I watched, we're reviewing a lot of science fiction shows for Alpha Quadrant 6 and I have two little kids and it's it's been really hard for me between work and my kids to find time for TV. But my wife went away this week and I had a little free time and I was able to watch the what is it five episodes of Stranger Things oh man and I really, going into it I just felt like third season I'm not really expecting much because the─

B: Wait, fourth.

J: ─oh, I'm sorry you're right. The fourth season. Not expecting really anything. All the actors are pretty much grown up now. They're not the same people.

B: [inaudible recognizable.

J: I gotta tell you I was shocked at how much I enjoyed it and how great they all were. They all connect, you know what I mean? Like it's funny you a lot of times with children actors like you think but what are they going to be like when they grow up? Because there's lots of examples of actors not being able to do it anymore. But that is not the case and I love this show. I'm just into it. I really really like how complex the story is. It's not a light story. It's definitely, like there's a lot of darkness and seriousness and it's really good horror. It's just really really good.

S: I was worried about it because the first season was magic. It was just so different. Very very enjoyable. The whole 80s vibe was really fun. Everything about it was was really enjoyable. And then second and third seasons we're good but you can't capture that magic again but the fourth season I think is better than two and three. Nothing's gonna be as good as the first one.

C: Do I need to have seen three?

S: Sort of. Yeah.

C: Because I kind of gave up. I loved season one also but season two just became like overly fantasy and like not... It didn't have enough other stuff to hook me. It was a little just bit just like too fantastic and so I kind of gave up in season two.

E: I watched it at two times speed. Half the time.

'C: (laughs) It'll be chipmunks.

S: Yeah I mean season three was good but four I think is the best season since one.

B: I mean just from a pure consistency point of view I mean this is the fourth season and they have maintained. They did not have a big drop off where you're like oh what happened. Cara's comments not outstanding of course but they kept it up. They kept it up and kept most of our interests and enjoyed that. But now four is actually even better. It's the best one since the first and if you enjoyed the first season definitely jump back in. Because it's good stuff. Those Duffer brothers I want to research them because they're kind of killing it. Good for them.

S: What about you Evan?

E: Well it was June 6^th recently which was of course the anniversary of D-Day and always around this that time of year there's all sorts of shows on television. War stories, war movies, documentaries, interviews, all having to do with a lot of World War II stuff obviously. So something that popped up recently on my Netflix account was what? Operation Mincemeat.

S: Yeah.

E: Which is a movie I had not seen before.

S: Saw that. Really good.

E: And the reason I, yeah and I bring it up because I'm familiar with the background of the story what the operation was by. A spy operation or to throw the Germans off. But there were certain things I learned about the operation that I learned through the movie that apparently are true that I hadn't learned before in other books that I've read or shows that I've watched. So I was very satisf--I'm always satisfied to learn more after having seen something and I walk away with something a little extra.

S: I love watching stuff about World War II. I don't know why. And there's like so many different stories to tell. So much happened in those four years. Yeah it's endless. But there's just something fascinating about. I guess because you're dealing with like the Nazis are just great villains, you know I mean?

E: Yeah.

S: They're iconic villains.

C: And there's a moral like we all agreed morally. I mean it took us a while to get there sadly but once we did we all agreed morally it wasn't like a divisive war the way that pretty much every war since then has been.

S: It was militarily very complicated. Every time I watched something about it I learned something new you. Really was just fascinating from so many different levels.

J: I don't think I could ever truly wrap my head around that entire war and all the little jigs and jags that happened. I mean so many people were involved and so many different big things happened that I never seemed to really understand like the big brush strokes of that war.

C: Right and on two completely different fronts.

E: Two theaters.

C: Yeah two theaters with multiple countries involved in both and yeah it was you're right very complicated.

J: But think about like there is an endless supply of drama that could be linked to that war. I've seen horror movies about World War II. I've seen thrillers about World War II.

B: Comedies.

C: Comedies, yeah. Video games.

J: Everything is in there. Like it literally encompasses like the spectrum of a human experience. You know what I mean?

E: Yeah it is overwhelming. It's a lifetime of consumption of information that you could have. And you can and walk away wanting more. Wanting to learn more.

S: All right well talking about learning more we're going to move on with our news items. We got some interesting stuff lined up for you today.

News Items

Infantile Amnesia (9:25)

• Why can't you remember being born, learning to walk or saying your first words? What scientists know about 'infantile amnesia'

S: Cara you're going to start us off with a discussion of infantile amnesia. Why don't we remember things from when we were like one year old.

C: Yeah. And I think this is a it's a fun story that I came across that was published in the Conversation by a psychologist at Rutgers named Vanessa LoBue or Lobu. I'm not sure. Yeah this isn't really based on any new big discovery. No big new publication but sort of a compilation of what she knows because this is her I guess area of expertise and she teaches child development. And so let's pose that question to you all because it's, as you might guess, a multifaceted answer. Why do you think we don't remember things from when we're babies?

J: I would say that parts of our brain aren't developed enough.

E: Yeah the recorder part of our brain isn't fully functioning at that point.

C: We're missing some hardware, yeah. Okay

B: Something about the hippocampus?

C: Something about the hippocampus, yeah.

S: I don't think it's anything like that because we learn, right? When you're one or two years old. You're not like you haven't learned stuff. It's really─

B: But that's different memory though.

S: ─ I always thought it was mainly due to the fact that we don't have a language. We don't have something to anchor those memories. But it could just be also that just it is a brain development thing.

C: And so researchers think it's kind of all of the above and then some additional stuff that we'll talk about. But I think you brought up something important Steve that Bob you questioned which I think is also an important conversation to be had here which is what's the difference between learning and memory? I think in some ways I come from psychology but by way of neuroscience. And it's also it's always been really interesting to me having one foot in kind of each pool to see how neurobiologists and how psychologists describe similar concepts using their own sort of constructions. And so very often you'll see that in cognitive psychology there are descriptions of things like memory that are somewhat different than the way neuroscientists might describe memory. For me personally learning and memory are sort of flavors of the same thing. And I'm curious Steve if is it safe for me to assume that based on your statement that you kind of see them the same way. They're sort of interpretations and different utilizations of very similar neural processes.

S: But we know that there are different kinds of memory. There is operational memory learning stuff. And then there's autobiographical memory learning, remembering your life. And it's what infants lack is the autobiographical memory. But they're still learning about the world. They're learning language, they're learning to recognize people etc.

C: Absolutely so when we think about memory we can kind of divide it into two main types. We often divide it into long term and short term or working memory. Long term memory is all the stuff that actually is retrievable. And short term memory, working memory is sort of it's the very short time that you're keeping something in mind before encoding it or before transferring it into this long-term memory. Short time memory is seconds. It's like active attention. Maybe 20-30s or less. Then working memory is the memory that we're implicitly deciding to utilize or not. We're comparing it to other things matching it up with our experience and we're starting to figure out whether or not it gets encoded. If it doesn't get encoded then it's lost. Long term memory is anything that's encoded but I think there are briefer engagements with long term memory. You can encode something and then never access it again. Or you can encode something and then rehearse it all the time and access it a lot. Which as we know, we've talked about this a lot on the show, we're not tape recorders. Every time we rehearse something it changes a little bit. So short term the shortest. Then working. Then long term. But regardless, Bob you're right, when we talk about these big those are the big distinctions. But when we really talking about today is types of long term memory. And as you mentioned Steve there's autobiographical memory. There's also declarative memory sometimes we call it explicit memory. Then there's implicit memory. So think about it this way: autobiographical is parts of our life. It's our relationship to our memory. It's sort of our narrative. Our chronology. Explicit memory is like in 1492 Columbus sailed the ocean blue. It's things that are conscious that you can declare. That you can say out loud. And then implicit memory is think about things like rote repetition it's sort of like remembering how to get somewhere─

B: Yeah, unconscious.

C: Yeah like a procedural memory. Things like that. There's so many different labels for this stuff. But sort of implicit, unconscious and very often you would relate that to sort of rote learning.

B: So I think for this task for this specific topic we're definitely gonna we need to focus on explicit memory which is conscious. Not implicit. We're talking about conscious explicit memories from when we were really young.

C: Really we're talking about autobiographical memory like Steve said.

B: But I think that's a labeling thing because my understanding when you talk about long term you use explicit and implicit─

C: [inaudible]

B: ─as you said. But then explicit is something that I think where you need to go down that road And there you see things like declarative memory which is facts and events. And then they further brake that down into these are the two that I think are the crooks. Episodic which is events and experiences which is what we forget. then there's semantic which is facts and concepts. So facts and concepts are retained it seems from that young age. But the episodic events and experiences that's what really that we don't remember. At least according to this labeling system. Episodic and semantic.

C: And some people my argue that the episodic is only even that that it's not explicit. That really you're not retaining much of that but you really only retaining explicit memory because of the age and because some of the factors that we've described. There are million different ways to, we talk about this constantly actually. This is a larger conversation but about taxonomy. About categorization. And there's again, I always recommend this book when we get on this topic, by Lulu Miller called Why Fish Don't Exist. And it's really about this concept. How do label things. How do we make meaningful distinctions. And sometimes they're meaningful depending on the field you're in. Depending on the specific topic you're talking about. But let's use a term which is not a perfect term. It has fuzzy boundaries. But this term autobiographical memory. This sort of self-referential memory. This memory for our own lives. Because that seems to be what a lot of researchers do sort of home in on when we talk about infantile amnesia. Infantile, I don't know why that word makes me laugh. Sounds like a rectile.

E: Describes an adult over [inaudible].

B: Oh my gosh.

C: Infantile dysfunction. That's like, I don't know why that's funny to me.

B: I'll always link those words.

C: (laughs) Sorry. So but basically if we were to say tell me a memory from where you were young very often people recall memories from like starting around 3-4-5 years old. Very rarely if at all─

E: And who knows how accurate.

C: ─and who knows how accurate, right.

B: [inaudible]

E: It'd be totally contaminated.

C: But very rarely do we hear much about something that happened when somebody was one. And researchers think that we may not be able to develop these autobiographical memories at that age. But it is very true as Steve mentioned as we were just grappling with Bob but of course we're learning when we're young. And learning requires that you hold things in your memory. So there are super early examples of experiments that show kind of without a shadow of a doubt that infants know their own mother's face. They can recall it. They can distinguish it from strangers. The longer that they're exposed to faces the more they can recognize them and we have different ways of measuring this that aren't always perfect. There are gaze tests that are often used with with infants. Some people argue that these aren't appropriate because kids will look at things for longer periods for lots of reasons. Sometimes it's about novelty. Sometimes it's about memory. But there is a study that was detailed in this article that I'm referencing that, well not a study, a series of studies that were done by Carolyn Rovee-Collier and she was a Rutgers psychologist who unfortunately died in I think 2014 but she was kind of really instrumental in helping us understand learning and memory in infants. And she did these really cool experiments where she would put babies in cribs and they would watch a mobile and they would they would see how often. So babies would watch a mobile because it was interesting to them. And babies also kick because that's what babies do. They kick their legs. And then what they did after they got baseline measurements of gaze and of kick activity. Is they tied a string between the baby's leg and the mobile. This is very low tech and I love it. And very quickly the baby learns hey if I kick the mobile moves. That's fun. And so babies often will kick significantly more often once they learn that. And so there is a certain amount of learning that you're seeing there because they change their behavior based on this feedback. And they did they adapt it for older children as well. But what we don't see for example. And this is I think an important aspect of autobiographical memory is we don't see children passing the mirror test when they're really really young. Takes them a while. I think not until they're about 18 to 24 months will babies when they're looking at a mirror notice a mark on their face. Recognize that it is their own face and start to try and wipe it off. Prior to that they don't seem to recognize themselves in the mirror. They see a baby. Like their eyes are fine but they don't have that concept of self. And so then that raises the question. Can we form memories about ourselves if we don't even have a concept of what selfness is. That's I think it's somewhat philosophical. I don't know if we could ever answer it neurologically but I think it's an important question. And then of course we add to that the fact that until like later in the second year we don't develop language and of course how much is memory tied to language as you mentioned Steve. We've all we've often talked about embodied cognition that language helps us label things and we label them in a way that they relate to to our person. If you think about the way that the words that we often use prepositionally speaking they're very much geometrically relational. Above, beneath, under, within. They have to do with this concept of space and of where we fit within space. And as we develop language we're also developing, or actually a little bit later, first we're developing this kind of sense of self. Then we're developing language. And then as you mentioned I think Bob mentioned it and Jay did as well. The hippocampus simply isn't developed in infancy. So there probably are some purely neurological limitations as well. And really what are we talking about? We may be talking about emergent properties here. All of these things aren't it's not a sense of self and language, and hippocampal development, and frontal lobe development. I mean these things all play off of each other. And in some ways are the same thing. They rely on one another and they're just different ways that we conceptualize them. So it does seem to be that there are some fundamental limitations for developing autobiographical memory. But! I'm catching myself even in that statement. Maybe we do develop them. Maybe we do encode them. We just can't retrieve them. And there's really no way to know.

B: They're there waiting for us to [inaudible]

E: We need AI.

J: What like you like Cara are you saying that these things are encoded in like a baby brain format that we no longer can access?

C: Could be. I mean there's really no I mean I don't know. That's a gross hypothesis but there's really no way to know i mean the thing about memory is that we don't know it's there unless we can evoke it. And so we are capable of retrieving through will. There are also examples where we can prime memories and then there are examples, there are some really cool examples, and Steve you've probably been just as fascinated by these studies as I have through the years where during deep brain stimulation surgeries memories are evoked simply through neurology. Like they're actually evoked. And that's kind of cool too because very often this is more of a cognitive process than a physiological process. But really it's hard to know because memory isn't a memory or it's not a memory that we can discuss unless we have both aspects. First we have to encode it but then we have to access it. We have to retrieve it.

E: Is there, what would be the advantage for a person, a small, young, an infant to be able to store the memory in such a way that it could be retrieved later in life? Is there an advantage or are we or is the brain wasting resources at that point?

C: I don't think I think in some ways that it might be a bias to think of it that way. Similar to like when we think about evolution as being advantageous. Like this is advantageous over that. Like that it's there's a goal at the end of it. I mean it just is a process that we develop with life. That's like kind of like saying what's the advantage of having memory as an adult. I mean there's a million reasons for it and it has to develop somehow and at some point in time. So I think I don't know. I mean correct me if you disagree with this but I think that this is just a function of we can point to the sort of developmental era at which this becomes codified. At which this becomes functional. But I don't think it's there's a why. There's a how but I don't know if there's a why.

E: I mean how busy is the six month old brain sort of just doing what it is.

C: Banana's busy. (laughs)

E: Yeah.

C: Well baby brains are so taxed. But we're they also sleep so so much because of that. But if you think about the amount of metabolism that's necessary for just starting to develop associations. Starting to learn. Pruning. So much of this neurological pruning is happening at this point. Neurons are firing. We're developing these hebbian synapses. So neurons are firing together and associations are being made. And we're actually laying down architecture and sort of losing other associations. There's a lot going on in those first few months. A lot. So yeah I mean that is an interesting question Evan and now now I guess I'm kind of seeing it for what I'm, correct me if I'm wrong, for what I'm thinking maybe you were pointing to which is from a purely efficiency. Like a metabolic efficiency perspective.

E: Right.

C: Why waste resources. Gotcha, gotcha.

E: Right, right. Yeah if it's running full capacity doing what it needs to do.

C: Right.

E: Why spend time doing something else that is, what, superfluous.

C: And it could be as simple as again not a why but a how. It not that there's any sort of choice in this but that it just isn't as important. It's taking a backseat to some of the more important processes and eventually it becomes more important.

E: It's low priority.

C: Yeah but it's a fascinating. I think we all sort of take for granted that babies don't remember stuff. It's like he won't remember it anyway but they are actively learning all the time. And we know little kids are total sponges the older they get too. But when they are infants, one and two years old, they are one and one and a half years old they're actively learning all the time but switch over to being able to tell stories about themselves. Understand who they are how they fit into the world. Develop language all of these things do seem to have a role. And it's clearly like most of the things we talk about on SGU, it's complicated. (laughs)

E: It's very complicated.

S: Cara what's your youngest autobiographical memory?

C: I can tell you that I have a like what I like to think of as a flashbulb memory. My first sort of evocative emotional memory. And I have no idea how old I was. I was maybe three or four. But we used to go to, what was it called? It was a burger place. Fuddruckers in Texas.

E: Yeah. We had one in Connecticut.

C: And the reason I think we went there is because kids under a certain age ate free with every adult. And I grew up when I was really really young it's still my mom and my dad. It was just me and my sister. So two free kid meals. But so we went there and I don't remember being there. I don't remember anything except having the balloon. They used to give you a balloon when you were a kid and you would eat there. And I came home, and I had the balloon wrapped around my wrist, and I was so excited. And we had these prickly bushes in front of our house.

E: Oh no.

C: And the balloon popped on the prickly bush. And it's, it's so funny but it's like my first feeling─

E: Of loss?

C: ─memory feeling of loss. And it's actually evokes like a lot of sadness in me when I think about it.

E: Oh gosh.

C: Isn't that funny? Like it's fundamental to later much more complicated and sophisticated experience of loss but I felt inconsolable. I had lost this thing that I loved. As in so far as a two or three year old or four-year-old can form those kinds of attachments. And I remember that feeling. What about you Steve? What's your first?

S: Yeah I was three. I have a couple of again those flash memories from being in daycare. One, probably the strongest is I was like in the kitchen area. Remember I was standing up but the table was over my head. So the room is huge in my memory. And I guess we were getting soup. It was beef and barley soup. And I remember that because I remember the smell and the smell always brings back that memory.

C: Oh right.

E: Interesting.

C: I love smell associations with memory.

S: A very strong odor-related memory.

The Age of Giants (27:23)

• Why don't we have many giant animals anymore?

S: All right Jay. This is an interesting question that I think many people may have asked themselves at one point or another. How come there aren't any giant animals anymore like the dinosaurs?

J: Yeah why were they able to grow so big and then what happened to the big animals?

E: So big.

J: (laughs) So you guys have all been to a museum of natural history. I mean I'm sure most of the people─

S: Oh yeah.

E: Several.

J: ─listening to this podcast. You've seen the bones, right? They're huge.

B: Look at the bones.

E: Look at the bones.

J: You stand at the base of a of some dinosaur displays and the thing is what 3040 feet tall? There's dinosaurs that were just absolutely strikingly enormous. And as a side note there was a lot of other animals that were huge too. Which you might not be aware of. There were giant ground sloths. There was a giant penguin that was six and a half feet or two meters tall and it weighed 250 pounds or 115 kilograms. That's a lot bigger than me. Dragonflies that used to have a wingspan of about 12 inches or 30 centimeters. And there is a 4.5 times the size. I'm sorry . Ad that is 4.5 times the size of a modern dragonfly. That's big. And of course a creature that can only be described as a monster: the Megalodon. It's a monster. It makes Jaws look like a joke. And these things were real.

E: I know I saw that.

J: And everybody seems to be okay with this. I just don't get it. (laughter) Anyway. So dinosaurs existed during the Triassic, Jurassic and Cretaceous periods. And one of those words had a movie named after it. And at the time the climate was a lot warmer as you guys know. CO₂ levels were over four times higher than they are today. So dinosaur remains have been found as far back. I mean this goes way back to the sixth century BC. When paleontology took off in the 19th century, since then scientists have been trying to explain why are these animals so big. Why were these freaking dinosaurs so big? What was it? What was it about the distant past that was different. And why aren't they anything like that here today. And the answer is... it's complicated. (laughter)

C: Yeah.

B: Got me again.

E: Oh gosh.

J: There are potentially a lot of answers. It's not one thing. It's not like oh because of blah they were big. It's like because of tons of things. First off let's talk about teeth. So let's say you're a baby dinosaur who is one day going to be huge. You're not huge yet but you're just a little tiny little critter there. Well you'd start out eating small prey. If you were that kind of animal that eats other animals. And you were lucky because you had these tiny little sharp teeth. They're perfect for killing small prey. And as you lost your teeth new ones would replace them like a shark, right? Now you're getting bigger and so do your teeth. Your teeth are getting bigger as well. And on top of that your teeth not only got bigger but they would change in type to suit the new prey that you were hunting.

B: Whoa.

J: Yeah. like it was already programmed of course into them. At this age the teeth are like this. And at this age they're bigger and they're like this. So they evolved to have different sets of teeth for different types of prey at different times in their lifespan. That's freaking amazing. Now let's go to bones. Dinosaurs could be as big as 100 feet long and weighing upwards of 45 tons. They were big so their bones had to be strong but their bones had to also be light. So some dinosaur bones had channels for air sacs that came from their circulatory system. This is like modern birds. They have extensive air sac systems. And this gives the bones the ability to be extraordinarily light but gives them strength as well. And this means that since dinosaurs had a lighter skeleton. They needed less muscle to power their movement. And this in turn reduce the amount of body heat that they produce. And this is the case this is not the case with modern mammals. Land mammals can only get to the size of roughly about an elephant maybe a little bit bigger but that's the limit. And warm-blooded animals require a lot more food as you know. If anyone has had a meal with me recently we require lots and lots of food. So a huge cold-blooded dinosaur would eat one-fifth of food of a modern elephant. Think about that.

S: Yeah but Jay I was reading that article and it struck me that it was a little out of sync with the news item from last week. Because the largest dinosaurs, the sauropods, were warm-blooded.

J: No we talked about it. I know I mean these are all, these are generalities you know what I mean?

S: This article was sort of like didn't update itself to that information yet. So they were partly speculating. Maybe they were only on the low end of the warm blooded sides. Like no actually they were fully warm blooded. So that wasn't really a factor in the size. Remember the whole gigantothermic thing was just not true.

B: [inaudible] consensus now?

S: This is news item from last week.

B: Yeah. I mean it's still percolating through.

S: Yeah, right. It just hadn't get it wasn't updated yet. So I think that one piece that doesn't jive with the most recent evidence on dinosaur warm bloodedness.

J: Well if they were cold-blooded they would have eaten one-fifth of food of a modern elephant. But yeah there is more recent information. The environment. So let's talk about what was their environment like. So another factor that allowed dinosaurs to be as big had to be their environment. There had to be plenty of oxygen and food to cover their needs. Their habitat in particular. It had to be just right. It had to be the perfect mix of things in order for these giant creatures to come into being. They required ecologies that were at the beginning of when the dinosaurs first started to appear the environment was already there. Like it was waiting for them. So since CO₂ levels were higher like I said this gave plant life this huge boost of making. It was a great time to be an herbivore let me put it to you that way. Plants of all varieties were everywhere. And we're talking about like everywhere. Like north and south pole as well. Wherever there was land and dinosaurs were living there was plants and they were in it and there was tons of herbivores eating through these plants and they had a seemingly endless supply of food. Now as we know more carbon dioxide is directly correlated with increased global temperature. So I've read that the daytime average temperature was 90 to 100°F or 32 to 38°C.

E: That's average.

J: Yeah. Yep.

B: That's nuts.

J: That's f--ing hot. That's really hot. (Cara laughs)

E: That is balmy. That is humid. So more oxygen also likely played a big role in allowing for giant insects as well.

B: So insects were critical. I think that you could say that the oxygen was probably overwhelmingly critical. More so perhaps than dinosaurs. This increase in oxygen. How high did it get? Was it like 20%? Yeah. Compared to that was like the main reason. The main reason. Otherwise insects just couldn't get that big without that much oxygen.

S: Do you know why that is, why that's so important for insects? Because they don't really have circulatory systems. The oxygen diffuses through their tissue so there's just a limit on the distance that the oxygen can diffuse. So you increase the oxygen tension even by a few percent─

B: More diffusion.

S: ─more diffusion. They can get bigger. They can have basically they could have parts of their body farther from their skin.

E: Huh.

J: All right let now let's click over to size. So once large bodies did evolve, which took a very long time, it gave those dinosaurs more protection from predators. If the dinosaurs grew big enough like for instance the hadrosaur even a pack of tyrannosaurus couldn't bring it down because it was just too big. Now let's talk about skull size. Some dinosaurs had large head ornamentation. You've seen tons of pictures of really weird shaped dinosaur heads and all this stuff. So they used these heads to fight. They were very very very likely to attract mates and the sheer size of the head itself could have given dinosaurs more protection. Think about this. The skull is bigger, thicker, heavier. One study showed that dinosaurs with large head features evolved to larger sizes 20 times faster than those without. So there was a huge boon to having a large bulky head. Not so much today but back then it was really in. Now time was another factor. Another thing that we have to consider here is that it took the dinosaurs an incredible amount of time to evolve to be this huge. There's so many things that had to change in order for the dinosaurs to get up to these sizes. During that time the habitats had to be very stable and consistent. Which it happened to be. So that's why they were able to live for so long and be so prosperous. Now as the environment slowly changed again. So millions of years going by and the environment is now getting cooler. It's possible, right? Like that an asteroid impact hit and if that did it probably very quickly killed off all the largest creatures out there because their food supply and environment and habitats were significantly disrupted. Now we have this big dying off of these large creatures. So now it comes in the smaller animals. And smaller animals were also during these times learning to have their social structures were starting to develop. And they were learning to hunt in packs which enabled them to take down larger prey. That was another thing that even reduced the size of the remaining largest animals, however large they were, all the way up into modern times where we killed off the closest thing to an elephant at the time. Because we were hunting them into extinction. So like I said. Tons of factors. All mish-mashed together. There's probably dozens and dozens more that we don't even know about of course because we don't have live specimens, we don't really know what the environment was exactly like. A lot of things are speculation. But these are very likely things that had an impact on why they could get that big and then the dying off and the larger animals kept getting killed and taken down and the environment kept changing. Until we get to the point where the largest creatures today live in the ocean. We have whales as the largest creatures and they're supported by the their body weight is supported by water. Of course they couldn't live on land. So land animals really have come way down in size to where we're looking at modern day elephants.

S: And average sizes. I mean they increased for a while among the mammals. There was the age of gigantism. Not anything close to dinosaur size but everything was big. Mainly because of competition. So the prey gets bigger so they're protected from predators so predators get bigger to eat the bigger prey. So there's like an─

B: Arms race.

S: ─arms race of size. So but then that takes time to play out. But then the trend reversed which a lot of researchers attribute to human hunting. We basically kill off the biggest animals because they're the most meat. And so the average size of mammals has been decreasing over the last twenty-thirty thousand years. One argument I didn't buy was the there just hasn't been enough evolutionary time to get that big. Because the biggest creatures to ever live are alive now. The whales. As you said. And they evolved in the last 60 million years. There has been enough time for creatures to get bigger than the biggest dinosaurs. I think the it's just that mammals can't get that big. Reptiles are just different. Reptiles continue to grow throughout their life unlike mammals. They have the lighter bone structure. They replace their teeth more often so they can adapt to larger stages in feeding strategies etc. So there's like a lot of features that reptiles have that mammals simply don't have.

B: Yeah plus how fair is it to compare land dwelling reptiles to sea going mammals? In terms of size. It's probably it might be just easier to to grow big in the water because you got all the water supporting you so it's not it's difficult.

S: Yeah you don't need to evolve as many adaptations. That's true.

B: Just stay streamlined.

S: But tells you how complicated a question it is. There's so many factors involved.

E: Huge.

AI and Traffic Jams (40:05)

• AI Can Help Traffic Jams

Special Segment: Green Bank Observatory (55:45)

• Bob visits the Green Bank Observatory

Who's That Noisy? (1:10:12)

Answer to previous Noisy:

Bugle of a bull Elk during Elk rut

New Noisy (1:14:12)

[bellowing, buzzing, and low chirping, chittering animal sounds]

J: ... If you think you know this week's Noisy or you heard something cool--because you must have, because you have ears--please email me at WTN@theskepticsguide.org.

Questions/Emails/Corrections/Follow-ups (1:15:44)

Question #1: Science of Gun Regulation (1:17:04)

What Do We Know About the Association Between Firearm Legislation and Firearm-Related Injuries?

Science or Fiction (1:40:30)

Hidden Theme: Counterintuitive Results Steve reveals this _hidden theme_ after the Rogues make their guesses Item #1: A new study in yeast finds that about 75% of synonymous (or silent) genetic mutations are actually significantly harmful. Item #2: In a large Danish study researchers found that having shingles increased the risk of being diagnosed with dementia over the next 21 years by 10%. Item #3: An analysis of air pollution in China finds a significant association with higher socio-economic status and higher exposures to ambient air pollution.

Answer	Item
Fiction	Shingles and dementia
Science	Silent mutations are harmful
Science	Higher S.E.S., higher exposure

Host	Result
Steve	swept

Rogue	Guess
Jay	Shingles and dementia
Evan	Shingles and dementia
Cara	Shingles and dementia
Bob	Shingles and dementia

Voice-over: It's time for Science or Fiction.

Skeptical Quote of the Week (1:54:51)

What I love about experts, the best of them anyway, is that they get to their humility early. They have to. It's part of who they are; it's necessary for what they're doing. They set out to get to the bottom of something that has no bottom, and so they're reminded constantly of what they don't know. They move through the world focused not on what they know, but on what they might find out.
– Michael Lewis, American author

Signoff/Announcements

S: —and until next week, this is your Skeptics' Guide to the Universe.

S: Skeptics' Guide to the Universe is produced by SGU Productions, dedicated to promoting science and critical thinking. For more information, visit us at theskepticsguide.org. Send your questions to info@theskepticsguide.org. And, if you would like to support the show and all the work that we do, go to patreon.com/SkepticsGuide and consider becoming a patron and becoming part of the SGU community. Our listeners and supporters are what make SGU possible.

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Today I Learned

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References

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