WEBVTT - Where Did Human Intelligence Come From? 0:00:01.440 --> 0:00:04.240 Welcome to Stuff you should know, a production of I 0:00:04.360 --> 0:00:13.239 Heart Radio. Hey, and welcome to the podcast. I'm Josh, 0:00:13.320 --> 0:00:16.040 and there's Chuck and Jerry's here too, and this is 0:00:16.079 --> 0:00:23.319 stuff you should know, the brainiac condition. That's right. I 0:00:23.480 --> 0:00:26.240 was trying to think of something and I was truly blank. 0:00:26.920 --> 0:00:30.760 That's uh, that's how appropriate. It totally Chuck, because we 0:00:30.800 --> 0:00:33.600 are talking today about human intelligence in the origin of 0:00:33.680 --> 0:00:36.600 human intelligence, and it just seems super stuff you should 0:00:36.600 --> 0:00:38.720 know me for us to not be able to come 0:00:38.800 --> 0:00:43.320 up with a decent joke, you know, well Ed did 0:00:43.360 --> 0:00:45.720 that for us, actually, because I did want to shut out. 0:00:45.760 --> 0:00:49.360 We usually don't mention like section titles and stuff like 0:00:49.440 --> 0:00:53.320 that that's actually in our notes, but Ed drops because 0:00:53.320 --> 0:00:54.920 it's you know, it's for our eyes. But Ed dropped 0:00:54.920 --> 0:00:59.960 to Simpson's reference in his section title one of the 0:01:00.040 --> 0:01:05.720 great Simpsons references chimpan A to Chimpanzee was so great. 0:01:05.840 --> 0:01:08.240 That was from the Planet of the Apes musical, right, 0:01:09.000 --> 0:01:10.760 that's right. And I just I like to think is 0:01:10.800 --> 0:01:12.720 that as a little gift from Ed to us? Yeah, 0:01:12.959 --> 0:01:15.280 it definitely was, and it was well received too, So 0:01:15.400 --> 0:01:19.840 thanks ed Um and the reason Ed created a section 0:01:19.840 --> 0:01:22.800 called chimpaneze to chimpanzees because we're gonna talk about the 0:01:23.440 --> 0:01:28.039 lineage of humanity like where humans came from UM And 0:01:28.120 --> 0:01:32.080 despite that hilarious and clever um section title, we did 0:01:32.160 --> 0:01:36.000 not actually evolve from chimpanzees, but we do share a 0:01:36.040 --> 0:01:40.480 common ancestor from chimpanzee. So chimps and humans split off 0:01:40.480 --> 0:01:43.760 from a shared ancestor about six to eight million years 0:01:43.760 --> 0:01:48.080 ago UM, and that really kicked off a long line, 0:01:48.480 --> 0:01:55.280 very long process um of evolution where intelligence started to 0:01:55.360 --> 0:02:00.360 develop fairly early on. It just was really slow to start, 0:02:00.480 --> 0:02:04.160 and then over time it kind of picked up speed. Yeah, 0:02:04.360 --> 0:02:06.800 you found this some kind of cool statistic. There's a 0:02:06.880 --> 0:02:12.560 researcher writer named Richard Leakey and H Richard, and I 0:02:12.600 --> 0:02:16.760 think most people agree. They posit that there was what's 0:02:16.800 --> 0:02:20.280 called a big bang of human culture around the Upper 0:02:20.320 --> 0:02:25.200 Paleolithic time period where things were, like you said, slow 0:02:25.280 --> 0:02:29.080 going for so long, and things were measured in in 0:02:30.320 --> 0:02:34.639 eras before that, very very slowly over like hundreds of millennia, 0:02:35.440 --> 0:02:39.440 and then all of a sudden, like sixty two thirty 0:02:39.480 --> 0:02:42.840 thousand years ago or so, things started to really ramp 0:02:42.960 --> 0:02:48.040 up in terms of innovation and intelligence. And uh, just 0:02:48.160 --> 0:02:51.720 really moving the ball forward to use a football metaphor, 0:02:52.200 --> 0:02:56.200 and we're talking about you know, clothing and uh, social 0:02:56.200 --> 0:02:59.480 structure and in art and creativity and stuff like that. 0:02:59.560 --> 0:03:01.840 So it's kind of cool to think, and you know, 0:03:02.200 --> 0:03:04.040 we're going to talk about why that might have happened, 0:03:04.040 --> 0:03:08.200 but uh, the fact that that did happen got us 0:03:08.320 --> 0:03:11.160 on the moon in short order over the last few 0:03:11.200 --> 0:03:13.680 thousand years. It's kind of like if you look at 0:03:13.720 --> 0:03:16.799 the development of intelligence as a train that's starting from 0:03:16.800 --> 0:03:19.760 a stop, it starts out with kind of a chuck 0:03:20.120 --> 0:03:23.800 good chug good chug chug chugga chug a chuga, and 0:03:23.800 --> 0:03:27.840 then that um, that Upper Paleolithic Revolution, the big bang 0:03:27.880 --> 0:03:32.400 of culture. That's the cho choo part that really punctuates 0:03:32.440 --> 0:03:35.160 the whole thing. I was thinking more along the lines 0:03:35.200 --> 0:03:38.320 of it like a Japanese bullet train. But sure, I 0:03:38.320 --> 0:03:42.280 don't think we're OK. We still do some really stupid stuff. 0:03:42.360 --> 0:03:45.840 So we can also create a bullet train. We can, 0:03:46.120 --> 0:03:50.000 but we just can't be the bullet train intellectual. Oh man, 0:03:50.400 --> 0:03:53.880 mind blown. So chuck. The fact that thirty to sixty 0:03:53.920 --> 0:03:57.720 thousand years ago there was that Upper Paleolithic Revolution where 0:03:58.080 --> 0:04:03.440 humanity just suddenly blossom into what we recognize today as humanity. 0:04:03.600 --> 0:04:07.360 It's really tempting to think that human intelligence just was 0:04:07.440 --> 0:04:12.280 suddenly born all of a sudden, like geologically speaking, overnight 0:04:12.880 --> 0:04:15.840 at that time. But that's just not the case. Um. 0:04:16.440 --> 0:04:20.000 It seems like something definitely happened there, like some wire 0:04:20.080 --> 0:04:23.440 connected with another wire that really made a big difference. 0:04:23.839 --> 0:04:26.440 But instead, again, it was this part of this very 0:04:26.560 --> 0:04:33.080 long line of seemingly random and unconnected um developments in 0:04:33.160 --> 0:04:36.120 the in the history of humanity. And I guess our 0:04:36.200 --> 0:04:40.760 our genus Homo um that led to that point and 0:04:40.800 --> 0:04:43.799 actually led to that point today, because we're still evolving 0:04:43.800 --> 0:04:46.880 and developing. Yeah, I guess uh. If you look at 0:04:46.880 --> 0:04:50.240 it on a timeline, it looks like a mechanic came 0:04:50.279 --> 0:04:53.240 along and said, well, here's your problem. You forgot to 0:04:53.279 --> 0:04:56.320 plug you forgot to plug it in. That's right, you 0:04:56.400 --> 0:04:58.520 gotta plug these two wires together and then you're all 0:04:58.520 --> 0:05:04.480 set totally. But we like to talk about Homo sapiens 0:05:04.560 --> 0:05:09.960 in in terms of human intelligence for good reason. Homo sapiens, 0:05:10.000 --> 0:05:13.520 that is to say, us a k a. Modern humans 0:05:13.560 --> 0:05:17.520 evolved about three hundred thousand years ago, um. But we 0:05:17.600 --> 0:05:22.560 are just one of a collection of uh in in 0:05:22.600 --> 0:05:27.279 this big lovely family called the Hominem's yeah, cominens comin 0:05:27.400 --> 0:05:30.440 in Yeah, I think it's at ms. Yeah. So the 0:05:30.480 --> 0:05:35.840 hominins are everybody that um that started off branching from 0:05:35.839 --> 0:05:39.200 that common ancestor with chimps. That's the hominin line, and 0:05:39.360 --> 0:05:42.200 humans in our genus Homo that Homo sapiens are a 0:05:42.200 --> 0:05:44.800 part of, is just part of that hominin. There are 0:05:44.800 --> 0:05:48.560 other entirely different genus or genie i that make up 0:05:48.760 --> 0:05:52.040 the hominin line, right, that's right, And we should point 0:05:52.040 --> 0:05:54.560 out that sapiens actually is taken from the Latin word 0:05:54.560 --> 0:05:57.320 for knowledge, so it kind of all makes sense. It does. 0:05:57.640 --> 0:05:59.520 So the whole thing starts out it seems like as 0:05:59.560 --> 0:06:02.680 far back because we can tell um something again, like 0:06:02.800 --> 0:06:05.960 somewhere around six or so million years ago, there was 0:06:06.120 --> 0:06:11.839 a group of homonyms called Artipithecus um who basically walked upright. 0:06:11.920 --> 0:06:15.960 But that was essentially the big difference between them and chimpanzees. 0:06:16.400 --> 0:06:21.080 But as we'll see, that was a really really big difference, right, Yeah, 0:06:21.080 --> 0:06:23.000 I mean we'll we'll get into this in more detail, 0:06:23.040 --> 0:06:26.039 but obviously if you're walking up right, then you have 0:06:26.080 --> 0:06:28.640 a very important thing at your disposal, which is use 0:06:28.680 --> 0:06:33.800 of your hands. Right, So then, um, you've got Australopithecus uh, 0:06:33.839 --> 0:06:36.760 and some a few other different kinds of branches that 0:06:36.839 --> 0:06:41.400 kind of branch off. It's a really tangled, convoluted family tree, um, 0:06:41.440 --> 0:06:44.400 where some kind of lead to blind alleys, others lead 0:06:44.400 --> 0:06:48.320 to others. But um, they think that Australopithecus is was 0:06:48.360 --> 0:06:51.799 a really big, long lasting group that was a little 0:06:51.800 --> 0:06:55.400 more human, definitely more human than art Epithecus um, but 0:06:55.480 --> 0:06:59.680 not quite as human as the genus Homo um, which 0:07:00.200 --> 0:07:03.600 off all of these different species of human Because we're 0:07:03.640 --> 0:07:06.359 we're alive today, we're on you know, planet Earth, living 0:07:06.440 --> 0:07:09.880 here in two and every single human alive is a 0:07:09.880 --> 0:07:13.760 member of the same species. So like there's different kinds 0:07:13.760 --> 0:07:16.480 of cats, there's different kinds of fish species, there's different 0:07:16.560 --> 0:07:19.960 kinds of bird species. Um, there's only one kind of 0:07:20.040 --> 0:07:22.360 human species. But that wasn't always the case. There are 0:07:22.360 --> 0:07:26.400 plenty of different human species, some living alongside one another 0:07:26.760 --> 0:07:30.160 for tens or hundreds of thousands of years, that's right. 0:07:30.480 --> 0:07:34.560 And almost all the hominins used tools, it seems like, 0:07:34.600 --> 0:07:37.720 and make made tools, and for a long time we 0:07:37.760 --> 0:07:40.640 thought that that was sort of it, that only the 0:07:40.680 --> 0:07:43.800 Homo genus was the one who did use tools, which 0:07:43.840 --> 0:07:45.720 is and you know, we talk about things like being 0:07:45.760 --> 0:07:48.679 bipedal and using tools as sort of some of the 0:07:48.760 --> 0:07:52.320 building blocks of what would become human intelligence. But now 0:07:52.320 --> 0:07:56.280 we know that there are uh some older you know, 0:07:56.720 --> 0:08:00.000 we found evidence that they use tools before that. Uh 0:08:00.080 --> 0:08:03.760 that's kind of fairly recently, right, Yeah. We we wanted 0:08:03.800 --> 0:08:07.920 to say that toolmaking started sometime after the Homo genus 0:08:07.960 --> 0:08:10.920 showed up of a couple million years ago, um, but 0:08:11.080 --> 0:08:14.640 we found even older tools. So it seems like austral Epithecus, 0:08:14.640 --> 0:08:17.640 which again their hominance, they're part of the branch that 0:08:17.760 --> 0:08:20.720 led to us humans, but they're not human in any way, 0:08:20.720 --> 0:08:23.400 shape or form um. So the fact that they're using 0:08:23.440 --> 0:08:26.320 tools was kind of mind blowing, and it also really 0:08:26.400 --> 0:08:29.559 kind of undermined kind of like what you were saying, 0:08:29.880 --> 0:08:32.400 like our idea of using tools, like that's a big 0:08:32.440 --> 0:08:35.680 sign of intelligence, and and humans are intelligent, so it's 0:08:35.720 --> 0:08:38.480 weird to find out that non humans were using tools 0:08:38.880 --> 0:08:43.520 millions of years ago. That's right. Um, should we move 0:08:43.559 --> 0:08:46.840 on to the hardware software thing? Yeah, So if if 0:08:46.880 --> 0:08:50.640 tools and fire are not, um, because we found use 0:08:50.679 --> 0:08:53.480 of fire dating back at least a million years. UM. 0:08:53.559 --> 0:08:57.520 So if if tools fire hanging out with one another collectively, 0:08:57.840 --> 0:09:01.800 if these aren't like the indicators that make human intelligence, 0:09:02.600 --> 0:09:05.439 we've got to like get a little more granular. Unfortunately 0:09:05.480 --> 0:09:08.520 for you and I sitting here today, chuck, UM, scientists 0:09:08.520 --> 0:09:09.960 have done that, and they've come up with some really 0:09:10.000 --> 0:09:14.200 interesting like ways of looking at this. Yeah, and UM, 0:09:14.280 --> 0:09:16.520 there's a bit more of a preamble before we get 0:09:16.600 --> 0:09:19.719 actually to the intelligence. UM. And I like the way 0:09:19.840 --> 0:09:23.880 ed put this, sort of like talking about hardware versus software. Um, 0:09:24.000 --> 0:09:28.360 they were very intertwined and um, you know, sort of 0:09:28.400 --> 0:09:30.760 happening at the same time. So it's not like one 0:09:31.000 --> 0:09:33.400 couldn't happen without the other as far as the hardware 0:09:33.440 --> 0:09:38.000 software thing goes. But Uh, if we're looking at hardware 0:09:38.040 --> 0:09:42.040 and we're talking about um changes that made us like 0:09:42.360 --> 0:09:44.560 better at walking up right, Like you can you all 0:09:44.600 --> 0:09:46.480 of a sudden just don't stand up and start walking 0:09:46.520 --> 0:09:49.079 like this happens over a long long period of time. 0:09:49.480 --> 0:09:52.600 Our hind legs got longer, Uh, the shape of our 0:09:52.679 --> 0:09:57.600 pelvis changed. Um. There's something called the Foreman magnum, which 0:09:57.679 --> 0:09:59.839 is a hole in the base of the skull where 0:09:59.880 --> 0:10:02.760 the spinal cord and lots of nerves and things passed 0:10:02.920 --> 0:10:06.000 like sort of open up those neural pathways, and that 0:10:06.160 --> 0:10:10.880 changed its location. So these literal physical changes are happening 0:10:10.880 --> 0:10:13.680 over great periods of time in order just to be 0:10:13.760 --> 0:10:17.240 able to walk up right right and and bipedalism it's 0:10:17.280 --> 0:10:20.959 like the defining characteristic of prominence. Right. There's there's not really, 0:10:21.160 --> 0:10:23.240 as far as I can tell, any other animals that 0:10:23.760 --> 0:10:27.520 that walk upright like by default. Um, so there had 0:10:27.559 --> 0:10:30.960 to be physiological changes, but they're not entirely certain why 0:10:31.040 --> 0:10:33.320 we started walking up right. But the fact that we 0:10:33.400 --> 0:10:36.719 did and it's lasted for this long means that there 0:10:36.760 --> 0:10:40.280 was some advantage to it because enough people walking upright 0:10:40.559 --> 0:10:43.080 were able to pass along their genes. And they think 0:10:43.120 --> 0:10:46.920 one one big theory is that it helped us survive 0:10:47.120 --> 0:10:50.040 climate change where maybe things got colder and there were 0:10:50.120 --> 0:10:53.199 less trees. So since we weren't arboreal anymore, we didn't 0:10:53.200 --> 0:10:56.079 hang out and live and eating trees. We were able 0:10:56.120 --> 0:10:58.800 to kind of move around and find different like food 0:10:58.800 --> 0:11:02.920 sources in different shelters, whereas the like our cousins the chimps, 0:11:02.960 --> 0:11:07.079 were in big trouble. They were up the proverbial creek. Yeah, 0:11:07.120 --> 0:11:09.160 and I love that you point out that we, uh, 0:11:09.280 --> 0:11:11.920 we're the only ones who walk upright by default, because 0:11:12.280 --> 0:11:14.439 I think we can all agree there's nothing more fun 0:11:15.120 --> 0:11:18.400 than YouTube videos of like a dog or a cat 0:11:18.480 --> 0:11:21.319 or something just walking on its hind legs for some reason. Definitely, 0:11:21.679 --> 0:11:23.960 and and it's the coolest and most fun thing ever. 0:11:24.160 --> 0:11:26.200 It totally is. And I mean, now I'll take like 0:11:26.400 --> 0:11:29.040 a Jesus lizard running across some water once in a 0:11:29.040 --> 0:11:31.800 while too. There's nothing wrong with watching. Is that what 0:11:31.840 --> 0:11:34.520 those are called? Yeah? I think I saw one of 0:11:34.520 --> 0:11:39.360 those in Mexico, but that was surprising. Are they not there? 0:11:39.679 --> 0:11:41.640 I don't know. I'm just saying I've I've never seen 0:11:41.640 --> 0:11:43.400 one in real life, so I'm sure that was surprising 0:11:43.440 --> 0:11:48.200 to see. I saw a lizard that was walking, and 0:11:48.280 --> 0:11:50.440 it wasn't walking on water, but I think it was 0:11:50.559 --> 0:11:52.440 one of those kinds that can I just didn't know 0:11:52.480 --> 0:11:55.120 the name of it. Had you recently eaten the worm 0:11:55.240 --> 0:11:59.680 from the bottom of the bottom of most cow? Very funny. 0:12:00.400 --> 0:12:03.440 Another thing we should point out is that walking upright 0:12:04.200 --> 0:12:07.199 is an energy saver. I mean, it's they've done studies 0:12:07.240 --> 0:12:10.520 and they found that um, you use about the energy 0:12:11.160 --> 0:12:14.040 um rather than you know, bounding around on all fours 0:12:14.080 --> 0:12:16.560 like a chimp mte right or like a chimp does. 0:12:17.120 --> 0:12:20.640 But to save that energy, to conserve it um, our 0:12:20.720 --> 0:12:23.240 pelvis has had to change shape. Like you mentioned, that 0:12:23.320 --> 0:12:27.080 was just a consequence of walking upright. Um. And the 0:12:27.120 --> 0:12:29.720 reason to change shape is when you walk up right, 0:12:29.720 --> 0:12:32.520 if you're a chimp, your body swings side to side. 0:12:32.559 --> 0:12:34.760 You have to hold your arms up to balance yourself. 0:12:35.120 --> 0:12:38.600 That takes a lot of energy. UM. So we developed 0:12:38.600 --> 0:12:41.800 like gluteal muscles and other muscles that can cling to 0:12:42.280 --> 0:12:46.200 a specific shaped in size pelvis so that we don't 0:12:46.240 --> 0:12:48.120 have to spend all the energy. Our muscles are just 0:12:48.200 --> 0:12:51.400 kind of keeping us much more balanced. But one of 0:12:51.440 --> 0:12:54.560 the consequences of that of walking upright and our pelvis 0:12:54.640 --> 0:12:58.679 changing means that the size of the birth canal afforded 0:12:58.720 --> 0:13:00.880 by the hole in the all of us the child 0:13:00.920 --> 0:13:06.400 passes through during birth. UM got smaller, a lot smaller. 0:13:06.880 --> 0:13:10.640 And it's really strange to think that this the the 0:13:10.760 --> 0:13:14.880 decreasing in size of the birth canal actually was one 0:13:14.920 --> 0:13:18.920 of the factors that led to an increase in intelligence. Yeah, 0:13:18.960 --> 0:13:20.640 and you know, we should point out this is just 0:13:21.160 --> 0:13:24.040 the first of what will be a lovely cascade of 0:13:24.080 --> 0:13:28.440 theories that we're gonna lay lay on your brains today. Uh, 0:13:28.440 --> 0:13:30.800 and that, like you said earlier, there there is no one, 0:13:30.920 --> 0:13:33.160 single one. It's kind of when you put all of 0:13:33.200 --> 0:13:35.720 this stuff together. I think that's sort of the beauty 0:13:35.760 --> 0:13:39.120 of of human intelligence, is it took all of these 0:13:39.280 --> 0:13:42.640 great things sort of coalescing um. But the whole thing 0:13:42.640 --> 0:13:47.120 with the brain is interesting because the size of the 0:13:47.160 --> 0:13:50.520 brain is is one of nature's kind of controversies. Like 0:13:51.320 --> 0:13:53.560 we know that as far as humans go, just because 0:13:53.600 --> 0:13:56.280 you have a bigger brain doesn't mean that you definitely 0:13:56.320 --> 0:14:00.760 will be smarter. But there are some correlations cross species 0:14:00.760 --> 0:14:04.360 in nature, uh, and in humans there can be, you know, 0:14:04.440 --> 0:14:08.320 evidence that bigger brain means you're more intelligent. But it's 0:14:08.360 --> 0:14:10.320 not one of those things where it settles science where 0:14:10.320 --> 0:14:11.959 they just say, hey, if you've got a bigger brain, 0:14:12.000 --> 0:14:14.440 you're gonna be smarter. No, And in fact, like there's 0:14:14.480 --> 0:14:17.960 all sorts of evidence in nature that suggests that's not 0:14:18.000 --> 0:14:22.280 the case. Because our brain to body size ratio among 0:14:22.400 --> 0:14:25.440 humans is one to forty, So our brain makes up 0:14:25.440 --> 0:14:29.080 about our body mass, and that's the same ratio that 0:14:29.120 --> 0:14:32.120 a mouse has. My mice just I don't care how 0:14:32.160 --> 0:14:35.000 you cut it. They're just not as intelligent as humans. 0:14:35.000 --> 0:14:38.280 But on the other hand, an elephants brain to body 0:14:38.400 --> 0:14:41.720 ratio is one to five hundred and sixty and elephants 0:14:41.720 --> 0:14:46.240 are super smart. So, um, you you can't really find 0:14:46.360 --> 0:14:50.760 much there that says, you know, there's no direct correlation 0:14:50.800 --> 0:14:53.440 where it's like the bigger the brain, the more intelligent 0:14:53.520 --> 0:14:57.680 the being. Um. But there does have to be some 0:14:57.840 --> 0:15:02.880 minimum amount of brain size because it seems like the 0:15:02.880 --> 0:15:06.080 connections of the brain is we'll see, are what really matter. 0:15:06.440 --> 0:15:08.880 And the more brain tissue you have up to a 0:15:08.880 --> 0:15:12.640 certain point, the more connections that can be made. Right, 0:15:12.720 --> 0:15:15.880 So that brings us back to the birth canal situation. 0:15:15.960 --> 0:15:18.480 Like you mentioned you're walking upright, that changes in the 0:15:18.480 --> 0:15:21.120 shape of the pelvis, you have a much smaller birth 0:15:21.120 --> 0:15:25.120 canal all of a sudden. So evolutionarily speaking, you might think, well, 0:15:25.680 --> 0:15:27.360 does that mean we're going to have to have babies 0:15:27.360 --> 0:15:30.840 with tiny, tiny little heads and therefore tiny tiny little 0:15:30.840 --> 0:15:33.680 brains that may not be able to grow very fast 0:15:33.800 --> 0:15:37.640 because it's enclosed in a skull that's sort of locked down, 0:15:38.840 --> 0:15:41.400 but that didn't happen to us. What happened was we 0:15:41.440 --> 0:15:46.040 have Fontanell's and we have this delayed fusing of the 0:15:46.080 --> 0:15:49.640 skull kind of you know, closing for good, and so 0:15:49.880 --> 0:15:52.760 it allows and it's you know, it's remarkable still to 0:15:52.760 --> 0:15:56.080 think about this to me, but it allows that little 0:15:56.120 --> 0:15:59.680 baby head to squish down to get through the birth canal, 0:15:59.760 --> 0:16:02.320 and it through the vagina and out into the world 0:16:02.960 --> 0:16:05.920 and stay that way for a while. And it's during 0:16:05.960 --> 0:16:09.560 that for a while period before that skull completely fuses 0:16:10.040 --> 0:16:14.240 that a human brain really really grows a lot, and 0:16:14.400 --> 0:16:18.080 chimps don't have that ability. No, a chimp, uh, their 0:16:18.200 --> 0:16:21.080 skull fuses mostly in the womb, and their brain, as 0:16:21.080 --> 0:16:24.880 a consequence, grows mostly to what size it's going to 0:16:24.920 --> 0:16:27.120 reach in the womb. So, on the one hand, a 0:16:27.200 --> 0:16:31.240 chimp baby, you could say, is much smarter and much 0:16:31.360 --> 0:16:35.320 less helpless than a human baby. But given enough time, 0:16:35.360 --> 0:16:37.520 the human baby is going to start to exceed the 0:16:37.600 --> 0:16:42.560 chimp's abilities very quickly. And it's because our development is delayed. 0:16:42.600 --> 0:16:44.720 We do a lot of developing outside of the womb, 0:16:44.880 --> 0:16:47.800 and that's afforded by that skull that's not fused. For 0:16:47.880 --> 0:16:51.160 a couple of years after birth. And this was not 0:16:52.080 --> 0:16:55.600 there is no intelligent design, so there this was not like, um, 0:16:55.640 --> 0:16:59.440 like a good solution or work around. This was just 0:16:59.640 --> 0:17:05.360 a natural selected, naturally selected trait, the skull not fusing. 0:17:05.640 --> 0:17:09.800 That was a solution to the smaller birth canal, not 0:17:09.880 --> 0:17:15.000 to not to increase intelligence, but the advent of babies 0:17:15.040 --> 0:17:18.919 being born that didn't have few skulls allowed for the 0:17:19.040 --> 0:17:22.960 advent of intelligence. Yeah, a solution to the problem of 0:17:23.560 --> 0:17:27.000 walking up right, which is really interesting to think about. Yeah, 0:17:27.040 --> 0:17:30.200 And it also just goes to show like it's like 0:17:30.560 --> 0:17:34.040 nature is not always like elegantly simple. Sometimes it's really 0:17:34.080 --> 0:17:37.679 convoluted and organisms including us are held together by like 0:17:38.000 --> 0:17:41.440 duct tape and bubblegum, you know. And that's a good 0:17:41.440 --> 0:17:44.560 example of it. I think that's a good time for 0:17:44.600 --> 0:17:48.800 the break, yea, yea. And we'll come back and drop 0:17:48.880 --> 0:18:13.040 some plasticity on your brain right after this, So, Chuck, 0:18:13.119 --> 0:18:15.720 this is the point we're about to talk about brain plasticity. 0:18:16.119 --> 0:18:22.600 This seems to be, uh, what if anything explains human intelligence, 0:18:22.640 --> 0:18:25.760 and certainly the burst of intelligence that happened thirty to 0:18:25.840 --> 0:18:30.360 sixty thou years ago. Yeah, And I think the opening 0:18:30.359 --> 0:18:32.440 statement to this whole thing is all you gotta do 0:18:33.200 --> 0:18:37.160 is look at the fact that we learn almost everything 0:18:38.240 --> 0:18:42.080 as humans, like from the moment we're born. There there 0:18:42.200 --> 0:18:45.159 is some maybe instinctive knowledge, but like you said, like 0:18:45.240 --> 0:18:48.879 human babies are kind of helpless, little dumb dumbs. And 0:18:48.960 --> 0:18:53.439 from that point forward, our brains are are learning and 0:18:53.480 --> 0:18:56.560 they're growing, and they're capable of learning, and they're capable 0:18:56.600 --> 0:19:01.160 of adapting. And this all has to do with plasticity, right, So, 0:19:01.400 --> 0:19:04.919 just if you aren't familiar, plasticity is the brain's ability 0:19:04.960 --> 0:19:10.160 to um basically rewire and create new connections as new 0:19:10.200 --> 0:19:13.520 experiences come along. Uh, And you can even take old 0:19:13.560 --> 0:19:17.639 experiences that you experience more than once and the second 0:19:17.640 --> 0:19:20.480 and third and fourth time, those neural connections are going 0:19:20.520 --> 0:19:24.719 to become more sophisticated and more connected than they were before. 0:19:24.920 --> 0:19:27.720 So our brains are plastic. They can be molded and 0:19:27.760 --> 0:19:31.000 shaped kind of like in the rhinoplastic um sense of 0:19:31.040 --> 0:19:33.760 the word. They're not made of plastic. They can be 0:19:33.840 --> 0:19:36.400 molded and they're molded by the connections that they make. 0:19:36.680 --> 0:19:39.560 So it's not necessarily that you have a giant brain. 0:19:40.080 --> 0:19:42.919 It's that you human being have a brain that is 0:19:43.119 --> 0:19:48.800 really highly capable of creating new connections, and it's those 0:19:48.800 --> 0:19:52.960 connections that forms the basis of intellect. Yeah, and that 0:19:53.320 --> 0:19:55.840 really frees up, Like once you have a brain that's 0:19:55.880 --> 0:19:59.640 plastic and that can evolve, you know, to figure out 0:19:59.680 --> 0:20:03.359 a pro ablem rather than taking eons and eons to 0:20:04.000 --> 0:20:07.840 have like genetic to genetically adapt to a solution to 0:20:07.880 --> 0:20:09.760 a problem. If all of a sudden you have a 0:20:09.760 --> 0:20:11.639 brain that can figure something out, you do it so 0:20:11.720 --> 0:20:14.640 much quicker, and that frees you up to do more 0:20:14.800 --> 0:20:18.840 and learn more, and it creates this feedback loop all 0:20:18.840 --> 0:20:21.399 of a sudden where the process really really speeds up. 0:20:21.440 --> 0:20:25.000 And that's you know, basically what we saw thirty sixty 0:20:25.359 --> 0:20:27.920 years ago. Yeah, and the reason and we're still seeing 0:20:27.920 --> 0:20:30.119 it today, Chuck. I mean, like you know, a thirty 0:20:30.200 --> 0:20:32.399 to sixty thousand years ago, it was a huge burst 0:20:32.440 --> 0:20:36.760 of creativity and intelligence, but we're still talking about changes 0:20:36.800 --> 0:20:39.520 that took place over thousands of years. Now. We're seeing 0:20:39.720 --> 0:20:43.920 changes to the human condition in our society that takes 0:20:43.920 --> 0:20:46.760 place over like tens of years. So it still seems 0:20:46.800 --> 0:20:48.560 to be speeding up and we're still going through the 0:20:48.600 --> 0:20:51.679 same process. But the I guess the best way to 0:20:51.720 --> 0:20:56.520 think about what you've just described as evolution, which typically 0:20:56.680 --> 0:21:02.160 you know, UM forces changes on us based on environmental conditions, 0:21:02.680 --> 0:21:06.200 goes into the brain, and now it's the brain that's 0:21:06.240 --> 0:21:08.919 able to change, and like you said, it changes much faster, 0:21:09.600 --> 0:21:13.240 and that leaves genetic evolution or genetic natural selection to 0:21:13.600 --> 0:21:17.879 focus on UM selecting for traits that create more and 0:21:17.960 --> 0:21:20.800 more intelligence. So it creates that positive feedback loop like 0:21:20.800 --> 0:21:23.879 you said, and speeds things up. It's pretty brilliant. So 0:21:23.960 --> 0:21:28.159 there's been a lot of really interesting research, especially in 0:21:28.160 --> 0:21:30.360 that it seemed like the early to mid nineteen nineties 0:21:30.400 --> 0:21:33.480 about plasticity UM. There are a couple of researchers name 0:21:34.000 --> 0:21:38.359 to Be and Cosmides great names, and they had a 0:21:38.480 --> 0:21:43.119 theory basically that human intelligence UH evolved with all these 0:21:43.760 --> 0:21:47.840 UM encapsulated cognitive models, so they did not have the 0:21:47.880 --> 0:21:51.520 ability to excess each other. Each each of these modules, 0:21:52.200 --> 0:21:55.480 and each one was very specialized for a very specialized 0:21:56.080 --> 0:21:58.320 problem or task that was trying to do our problem 0:21:58.320 --> 0:22:03.920 that was trying to solve, and that's like a language module, UH, 0:22:04.160 --> 0:22:07.800 spatial relation module. UH, here's how to make and use 0:22:07.840 --> 0:22:10.640 a tool that kind of a module. And that all 0:22:10.680 --> 0:22:13.920 these modules are still around, uh and basically the same 0:22:13.960 --> 0:22:18.919 form that they were back then, because it's there on 0:22:18.960 --> 0:22:22.199 the timeline of you know, humanity, that that hasn't been 0:22:22.240 --> 0:22:26.320 a lot of time to undergo any kind of modifications basically, 0:22:26.720 --> 0:22:28.879 So I disagree with that. I think I think on 0:22:29.000 --> 0:22:33.199 a speaking about classic evolution natural selection, that's true, but 0:22:33.440 --> 0:22:37.600 brain based evolution and natural selection like cultural natural selection, 0:22:37.640 --> 0:22:42.200 I think that that's false. You hear that to be. So. 0:22:42.359 --> 0:22:45.359 The the idea about all this is that these modules 0:22:45.359 --> 0:22:47.960 that we developed over time is like we came upon 0:22:48.080 --> 0:22:51.360 new problems in our environments and had to figure out 0:22:51.400 --> 0:22:54.520 new solutions to them. They started to kind of get 0:22:54.560 --> 0:22:59.000 cross referenced here there, Like you could say, um, you know, 0:22:59.119 --> 0:23:05.000 the same the same ability to UM to to follow 0:23:05.080 --> 0:23:08.080 the sunset, right, Yeah, I wish I would have come 0:23:08.160 --> 0:23:11.320 up with something better can also can also be used 0:23:11.359 --> 0:23:16.320 to UM to follow herds of game, right. And so 0:23:16.480 --> 0:23:18.600 all of a sudden we now not only just know 0:23:18.760 --> 0:23:21.200 to to follow the sunset if we want to follow 0:23:21.240 --> 0:23:23.120 the sunset, we also know we can use that same 0:23:23.160 --> 0:23:25.840 ability to follow game around. And all of a sudden, 0:23:25.840 --> 0:23:29.080 our diet expands that kind of thing. So as these 0:23:29.119 --> 0:23:33.560 different modules started cross referencing themselves and and got more 0:23:33.600 --> 0:23:36.760 and more connected. We were able to apply these different 0:23:36.800 --> 0:23:39.199 things to more and more situations and got more and 0:23:39.240 --> 0:23:43.560 more intelligent. All right, So that's UM. That's one sort 0:23:43.600 --> 0:23:48.280 of grand theory which I love. Another one that we're 0:23:48.280 --> 0:23:51.880 going to talk about is I think super interesting because 0:23:51.880 --> 0:23:55.879 some of this stuff is so kind of rudimentary in 0:23:55.920 --> 0:23:57.720 it when you just sort of look at it from 0:23:57.720 --> 0:24:00.359 a macro view, but when you really have to think 0:24:00.400 --> 0:24:04.160 about how important that ended up being, it's it's fascinating 0:24:04.200 --> 0:24:06.800 to me. And in this case, we're talking about the 0:24:06.800 --> 0:24:10.399