WEBVTT - From the Vault: Humans Throwing Stuff 0:00:06.240 --> 0:00:08.480 Hey, you welcome to Stuff to Blow Your Mind. My 0:00:08.600 --> 0:00:09.800 name is Robert Lamb. 0:00:09.880 --> 0:00:12.039 And I am Joe McCormick, and Rob and I are 0:00:12.039 --> 0:00:14.480 out this week, so we're bringing you an episode from 0:00:14.760 --> 0:00:17.600 the vault. This is sort of part four in our 0:00:17.640 --> 0:00:21.119 series that we started reairing last week about throwing behaviors 0:00:21.120 --> 0:00:23.280 in non human animals. But here we're getting, of course, 0:00:23.320 --> 0:00:27.360 to the emergence of throwing behaviors in humans and human ancestors. 0:00:28.040 --> 0:00:30.640 I hope you enjoy and oh this one originally published 0:00:30.680 --> 0:00:36.080 January twelfth, twenty twenty three. 0:00:36.159 --> 0:00:44.159 Welcome to Stuff to Blow Your Mind, production of iHeartRadio. 0:00:46.040 --> 0:00:48.080 Hey, welcome to Stuff to Blow Your Mind. My name 0:00:48.120 --> 0:00:49.000 is Robert Lamb. 0:00:49.320 --> 0:00:52.120 And I'm Joe McCormick, and we're back with part four 0:00:52.479 --> 0:00:56.200 of our series on throwing behavior. Now, in previous parts 0:00:56.200 --> 0:00:59.880 we focused mainly on non human animals. We've looked at 0:01:00.320 --> 0:01:06.640 alleged throwing behaviors in octopuses, in elephants, in the mongoose. 0:01:07.120 --> 0:01:09.920 We definitely had a digression about dogs with air Bud 0:01:10.040 --> 0:01:13.639 in the previous episode. But also in the previous episode 0:01:13.760 --> 0:01:17.480 we ended up talking about the evolution of the human 0:01:17.720 --> 0:01:22.120 capacity for throwing, which we are particularly apt at Humans 0:01:22.319 --> 0:01:25.800 are very good at throwing, especially compared to our nearest 0:01:25.920 --> 0:01:30.080 primate relatives. So like a chimpanzee maybe on average three 0:01:30.160 --> 0:01:32.800 or four times stronger than a human, But a human, 0:01:32.920 --> 0:01:36.560 even without specialized training, can generally throw a lot more 0:01:36.560 --> 0:01:39.200 forcefully and a lot better than a chimpanzee can. So 0:01:39.240 --> 0:01:41.759 why are we so specialized for throwing? Well, we took 0:01:41.760 --> 0:01:46.160 a look at some evolutionary hypotheses about where our capacity 0:01:46.200 --> 0:01:49.200 for throwing comes from. But there was another thing that 0:01:49.280 --> 0:01:53.160 I came across while researching this subject that I did 0:01:53.160 --> 0:01:56.280 not get into in the previous episode, and I wanted 0:01:56.320 --> 0:01:57.760 to come back to it here because I found it 0:01:57.800 --> 0:02:02.080 really interesting. And this is the idea of what if 0:02:02.120 --> 0:02:07.120 the evolution of throwing was somehow a necessary precursor for 0:02:07.200 --> 0:02:12.320 the evolution of probably the most distinctly human trait language, 0:02:13.880 --> 0:02:16.400 So not just that humans are good at throwing and 0:02:16.639 --> 0:02:20.440 good at language, but that there is actually a neurobiological 0:02:20.560 --> 0:02:24.799 link between the two one comes from the other. So 0:02:25.040 --> 0:02:29.120 to look at this question, I wanted to refer to 0:02:29.160 --> 0:02:32.560 a paper by William D. Hopkins, Jamie L. Russell, and 0:02:32.639 --> 0:02:36.600 Jennifer A. Schaeffer published in Philosophical Transactions of the Royal 0:02:36.639 --> 0:02:41.200 Society b Biological Sciences, published in twenty twelve, called the 0:02:41.320 --> 0:02:47.000 Neural and Cognitive Correlates of Aimed Throwing in Chimpanzees a magnetic, resonance, image, 0:02:47.040 --> 0:02:50.720 and behavioral study on a unique form of social tool use. 0:02:52.200 --> 0:02:55.160 So to begin, they cover some of the same ground 0:02:55.200 --> 0:02:59.680 we did in the previous episode. You know how unusual 0:02:59.760 --> 0:03:02.960 he when throwing behavior is in a way, and despite 0:03:02.960 --> 0:03:05.720 all the interesting examples we've discussed in these episodes of 0:03:05.760 --> 0:03:09.160 animals throwing things for various reasons, whether trained by humans 0:03:09.240 --> 0:03:11.960 or just doing it as part of their natural instinctual behaviors, 0:03:12.800 --> 0:03:17.120 the authors here argue that in general, throwing remains unsystematic, 0:03:17.320 --> 0:03:19.320 in their words, in other animals, And I think this 0:03:19.360 --> 0:03:24.440 is fair. No other animal practices the kind of generalized, 0:03:24.639 --> 0:03:28.720 skillful habitual throwing that we do, certainly not without training 0:03:28.760 --> 0:03:29.440 by humans. 0:03:30.200 --> 0:03:31.920 Yeah, as we discussed in the previous episode, it goes 0:03:31.960 --> 0:03:36.120 way back in human behavior, and it's something that even today, 0:03:36.200 --> 0:03:38.839 with all our other tools and ways of doing things 0:03:38.920 --> 0:03:44.120 at a distance, we still engage in throwing. I think 0:03:44.160 --> 0:03:46.360 in the very first episode we discussed that sort of 0:03:47.560 --> 0:03:51.600 at least in my case, this strange pull to need 0:03:51.640 --> 0:03:54.520 to throw a ball with my son when he was younger, 0:03:55.520 --> 0:03:59.240 even though we're not a baseball or softball family. But 0:03:59.320 --> 0:04:00.720 it was just kind of the thing that I guess 0:04:00.800 --> 0:04:03.680 was like nostalgic in the culture, but also very satisfying 0:04:03.720 --> 0:04:06.200 to do and something that even if you're not very 0:04:06.200 --> 0:04:08.720 practiced at you can do with some or at least 0:04:08.720 --> 0:04:11.040 I found that I could do with some degree of precision, 0:04:12.560 --> 0:04:15.640 despite being very rusty at the whole softball baseball thing. 0:04:16.200 --> 0:04:19.120 I totally sympathize with you there. I mean, I think 0:04:19.200 --> 0:04:21.719 neither of us are really sports guys. I don't really 0:04:21.720 --> 0:04:23.920 want rules, I don't really want teams, but I do 0:04:24.000 --> 0:04:29.200 want ball or frisbee. Frisbee just as good in my opinion. 0:04:29.839 --> 0:04:32.240 Yeah, And I mean there's also there's a lot more 0:04:32.279 --> 0:04:35.080 throwing that goes on too, Like how often do we 0:04:35.080 --> 0:04:37.880 find ourselves across the room from someone We request something 0:04:38.200 --> 0:04:40.120 and they give it a tok, they throw it to us, 0:04:40.400 --> 0:04:41.680 and you want to be able to catch it for 0:04:41.760 --> 0:04:44.920 various reasons. And then that's without even getting into the 0:04:45.000 --> 0:04:47.159 various sports that even if we don't engage in, we 0:04:47.240 --> 0:04:51.560 may watch and the throwing of balls is often an 0:04:51.640 --> 0:04:54.320 essential part, or at least one aspect of a given 0:04:54.320 --> 0:04:55.520 sport right. 0:04:56.200 --> 0:04:59.520 But of course, apart from these recreational concerns, you know, 0:04:59.640 --> 0:05:03.839 throwing has been crucial to the survival of our ancestors. 0:05:03.880 --> 0:05:06.200 That seems pretty clear. And in the last episode we 0:05:06.200 --> 0:05:10.560 talked about arguments from evolutionary anthropology that throwing was positively 0:05:10.640 --> 0:05:14.120 selected for in human ancestors, and the bodies of hominin 0:05:14.200 --> 0:05:18.760 species like Homo erectus show anatomical changes that seem to 0:05:18.800 --> 0:05:24.520 favor forceful overhand throwing. I remember those changes. They're changes 0:05:24.560 --> 0:05:27.000 in the shoulder and the waist and the upper arm, 0:05:27.120 --> 0:05:30.440 all of which combined to allow for a more substantial 0:05:30.600 --> 0:05:33.200 wind up, sort of a pulling back of tension of 0:05:33.680 --> 0:05:38.200 the biomechanical bowstring to be released rapidly during the throw. 0:05:38.839 --> 0:05:41.360 And we also talked about the argument that these changes 0:05:41.400 --> 0:05:44.760 appear to coincide with evidence of meat becoming a bigger 0:05:44.800 --> 0:05:48.200 part of the diet of these hominins, showing that throwing 0:05:49.080 --> 0:05:53.640 was likely useful for obtaining food, either through power scavenging 0:05:53.760 --> 0:05:56.479 like driving predators away from a kill in order to 0:05:56.480 --> 0:05:59.760 take the meat for yourself, or direct hunting, and either 0:05:59.760 --> 0:06:04.159 way increasing the availability of food energy. Now, one very 0:06:04.160 --> 0:06:07.800 interesting thing about the adaptation for throwing is that it 0:06:07.880 --> 0:06:11.960 implies not only changes in the muscles and the skeletal system. 0:06:12.080 --> 0:06:14.000 Of course, you know, you can see all those changes 0:06:14.040 --> 0:06:16.679 around the scapula and the shoulder blade, changes in the waist, 0:06:16.800 --> 0:06:20.520 the arm, and so forth, But it also implies changes 0:06:20.640 --> 0:06:25.720 in cognition. An animal that can throw objects sourced from 0:06:25.800 --> 0:06:30.120 the environment is showing a specialized way of thinking, and 0:06:30.160 --> 0:06:33.359 not just a specialized way of moving. Now what do 0:06:33.400 --> 0:06:36.039 I mean by this? Well, as one example, the authors 0:06:36.120 --> 0:06:40.240 reference a specific captive chimpanzee who came up in the 0:06:40.279 --> 0:06:43.560 last episode. Robie, remember the story of Santino, the chimpanzee 0:06:43.560 --> 0:06:45.880 who was in a zoo and I believe Sweden was it? 0:06:46.440 --> 0:06:46.839 I believe? 0:06:46.880 --> 0:06:51.480 So, yes, Ip Santino, Yeah, poor Santino. The authors right 0:06:51.600 --> 0:06:54.960 that Santino, who I guess was alive at the time 0:06:55.000 --> 0:06:58.400 this paper was written. Quote hydes rocks out of sight 0:06:58.480 --> 0:07:01.200 of the care staff, waiting to reveal and throw them 0:07:01.200 --> 0:07:04.960 at approaching visitors at the most opportune time. Evidence of 0:07:05.080 --> 0:07:08.520 planning comes from the observation that Santino searches for the 0:07:08.640 --> 0:07:12.280 rocks from a moat inside the enclosure prior to the 0:07:12.360 --> 0:07:15.800 arrival of the care staff and the visitors, and cashes 0:07:15.880 --> 0:07:18.360 the rocks out of sight, only to pull them out 0:07:18.400 --> 0:07:22.600 when the visitors arrive. That is a crafty chimp, and 0:07:22.240 --> 0:07:28.480 that is forethought. Adding to this, the authors throw in 0:07:28.520 --> 0:07:32.200 their own observations of similar pre planning behavior in chimpanzees 0:07:32.200 --> 0:07:35.400 in two other research environments, and they argue that the 0:07:35.440 --> 0:07:40.000 throwing quote, though often agonistic in function and consequence, agonistic 0:07:40.040 --> 0:07:45.200 meaningless confrontational aggressive behavior, is not part of the ape's 0:07:45.280 --> 0:07:49.520 display behavior. Indeed, most instances of aimed throwing that we 0:07:49.560 --> 0:07:53.840 have observed occur without any accompanying display behavior such as 0:07:53.840 --> 0:07:58.640 pilo erection, hooting, and charging, further suggesting an element of 0:07:58.720 --> 0:08:02.120 planning on the part of the individual ape. So I 0:08:02.160 --> 0:08:04.480 think that's interesting too if you understand what they're saying there, 0:08:04.640 --> 0:08:09.040 that there is a sort of standard display behavior algorithm, 0:08:09.160 --> 0:08:12.840 like when an ape is doing an agonistic display when 0:08:12.840 --> 0:08:15.960 trying to be dominant and aggressive and maybe scare you off. 0:08:17.080 --> 0:08:19.680 It includes all of these sub features like the pilo 0:08:19.720 --> 0:08:23.560 erection meaning the bristling of body hair, hair stands on end, hooting, 0:08:23.720 --> 0:08:27.200 charging back and forth, all that stuff. And they say 0:08:27.240 --> 0:08:30.080 that when the apes throw stuff at people, they do 0:08:30.160 --> 0:08:33.040 it without all of these other features of a typical 0:08:33.160 --> 0:08:37.000 instinctual display. Another way that throwing is different from most 0:08:37.000 --> 0:08:40.680 other forms of tool use and apes. The most commonly 0:08:40.720 --> 0:08:44.480 observed types of tool use by wild chimpanzees are all 0:08:44.640 --> 0:08:49.600 things where the tool is used to extract otherwise unreachable food, 0:08:49.760 --> 0:08:52.360 often like from a hole or enclosure of some kind, 0:08:52.920 --> 0:08:55.720 and then is eaten immediately. So examples here would be 0:08:55.800 --> 0:08:58.959 cracking of nuts with stones like nut cracking is an 0:08:58.960 --> 0:09:02.320 example of ape tool use, but also termite fishing with sticks, 0:09:02.440 --> 0:09:05.760 ant dipping, and so forth. All of these give rise 0:09:05.800 --> 0:09:10.040 to an immediate food reward for executing the behavior, meaning 0:09:10.360 --> 0:09:15.440 that these behaviors are subject to regular operant conditioning rules. 0:09:16.280 --> 0:09:19.480 You know, if a behavior leads to an immediate food reward, 0:09:19.720 --> 0:09:23.320 an animal can learn to repeat basically any arbitrary set 0:09:23.360 --> 0:09:27.200 of actions. So you know, chimpanzee gets delicious termites every 0:09:27.200 --> 0:09:30.160 time it. Of course, if it dips for them, that's 0:09:30.160 --> 0:09:32.200 one thing. But maybe if it stands on one foot 0:09:32.440 --> 0:09:35.040 and gets termites every time, it may learn to stand 0:09:35.080 --> 0:09:36.520 on one foot to get the meat. 0:09:37.120 --> 0:09:40.920 Yeah, and we see this reflected and so many experiments 0:09:40.960 --> 0:09:44.200 involving animals over the years. You know, can you get 0:09:44.600 --> 0:09:48.320 an animal to manipulate some sort of technological gadget in 0:09:48.440 --> 0:09:50.200 order to get a food reward. 0:09:50.240 --> 0:09:52.320 Yeah, pressing a button or something that would have no 0:09:52.400 --> 0:09:56.720 relevance in the natural environment. So other tool use behaviors 0:09:56.760 --> 0:10:00.839 could easily be learned and reinforced through this kind of conditioning. 0:10:00.920 --> 0:10:04.800 But throwing, as practiced by apes does not lead to 0:10:04.840 --> 0:10:07.720 an immediate food reward. In fact, it rarely, if ever, 0:10:08.280 --> 0:10:12.720 leads to a food reward at all the author's right quote. 0:10:12.880 --> 0:10:15.960 What appears to be the main reward for throwing is 0:10:16.000 --> 0:10:20.040 the simple ability to control or manipulate the behavior of 0:10:20.080 --> 0:10:24.480 the targeted individual ape or human, which, though you could 0:10:24.520 --> 0:10:27.400 consider it a goal, I mean that is much more 0:10:27.559 --> 0:10:31.200 complicated and ambiguous than a direct food reward. 0:10:32.120 --> 0:10:35.439 Yeah, because it's not like the ape in this scenario 0:10:36.120 --> 0:10:39.719 is throwing the rock, hitting the human, and then by 0:10:39.800 --> 0:10:42.160 hitting the human they drop an apple, right. 0:10:42.280 --> 0:10:46.160 Yeah. Now, from here, the authors go on to discuss 0:10:46.200 --> 0:10:49.760 the underappreciated complexity of throwing. We also talked about this 0:10:49.800 --> 0:10:52.520 at length in the previous episode. But you know, suffice 0:10:52.520 --> 0:10:56.240 to say, force full, precise overhand throwing is an extremely 0:10:56.280 --> 0:10:59.960 demanding task, not only for the muscles but for the brain, 0:11:00.160 --> 0:11:04.360 requiring split second coordination of perceptual judgments all kinds of things. 0:11:04.400 --> 0:11:06.160 You know, how far away is the target, is it 0:11:06.240 --> 0:11:08.880 moving in what direction? And how fast? What are the 0:11:08.880 --> 0:11:12.160 physical properties of the projectile and so forth. But then 0:11:12.200 --> 0:11:16.600 the other thing is the sequential motor control. To throw 0:11:16.920 --> 0:11:21.720 an object, you have to precisely time a rapid sequence 0:11:21.840 --> 0:11:27.800 of muscular movements, and other authors have previously suggested that 0:11:28.000 --> 0:11:33.239 quote the increased selection for neural synchrony of rapid muscular sequencing. 0:11:33.320 --> 0:11:37.880 Routines associated with actions such as throwing are similar to 0:11:38.240 --> 0:11:43.040 the motor programming demands of language and speech, and therefore 0:11:43.120 --> 0:11:50.160 engage similar neural systems, notably Broca's area. In other words, 0:11:50.240 --> 0:11:53.720 there are similarities between what the brain is doing and 0:11:53.760 --> 0:11:56.959 what parts of the brain are being used to coordinate 0:11:57.000 --> 0:12:02.560 a throw and to process language and speech. And one 0:12:02.559 --> 0:12:04.800 idea that gets wrapped up in this is the role 0:12:04.880 --> 0:12:10.600 of brain lateralization, segmenting of brain processes to one hemisphere 0:12:10.720 --> 0:12:13.600 or side of the brain or the other. So in 0:12:13.640 --> 0:12:16.240 cultures where throwing behavior has been studied, the authors say 0:12:16.280 --> 0:12:18.840 the majority of people pretty much always prefer to throw 0:12:19.040 --> 0:12:22.800 with the right hand. Studies in chimpanzees also show a 0:12:22.840 --> 0:12:26.840 bias toward right handedness for throwing, and these right hand 0:12:26.920 --> 0:12:31.320 preferences suggest left hemisphere dominance in the brain in these 0:12:31.400 --> 0:12:34.760 majorities of both populations, because when it comes to controlling 0:12:34.800 --> 0:12:38.360 the body's movements, of course, you know, the hemispheres are flipped. Generally, 0:12:38.400 --> 0:12:40.800 the left hemisphere links to the right hand, the right 0:12:40.800 --> 0:12:44.880 hemisphere to the left, and so forth. Some researchers have 0:12:45.000 --> 0:12:48.320 pointed this out in the context of the fact that 0:12:48.360 --> 0:12:53.520 the left hemisphere also contains the brain regions, notably Broca's area, 0:12:54.160 --> 0:12:57.400 that dominate the production of speech. Broker's area is also 0:12:57.480 --> 0:13:01.360 known as the motor speech area, and one researcher who 0:13:01.440 --> 0:13:05.280 has focused on this is the American neurophysiologist William H. Calvin, 0:13:05.320 --> 0:13:08.760 who was actually, I think maybe still is a professor 0:13:08.800 --> 0:13:14.280 at the University of Washington at Seattle, who observing that 0:13:14.360 --> 0:13:16.760 eighty nine percent of people prefer to throw with the 0:13:16.880 --> 0:13:21.680 right arm, Calvin hypothesized that the left hemispher's capacity for 0:13:21.840 --> 0:13:26.800 language may have actually evolved from a pre existing adaptation 0:13:27.440 --> 0:13:31.400 for right handed throwing. He apparently published a book that 0:13:31.480 --> 0:13:35.360 contained this hypothesis. In nineteen eighty three, it was called 0:13:35.400 --> 0:13:36.640 The Throwing Madonna. 0:13:37.440 --> 0:13:40.600 Oh didn't they adapted this into the film a lead 0:13:40.640 --> 0:13:41.360 of their own right? 0:13:43.280 --> 0:13:44.080 Was Madonna in that? 0:13:44.600 --> 0:13:45.040 I believe? 0:13:45.080 --> 0:13:45.120 So? 0:13:45.320 --> 0:13:45.520 Yeah? 0:13:45.520 --> 0:13:47.880 Oh, okay? Was she the picture in the movie? 0:13:48.320 --> 0:13:50.960 Ah? Oh, I don't remember, but I mean surely she 0:13:51.040 --> 0:13:52.640 threw a ball at least once. I mean there's a 0:13:52.679 --> 0:13:55.120 lot of throwing in baseball. 0:13:55.400 --> 0:13:57.319 Yeah, you throw, no matter what position you are. I 0:13:57.320 --> 0:13:58.600 guess the picture throws the most. 0:13:58.840 --> 0:14:01.280 There's no crying in baseball, but there was throwing in baseball. 0:14:01.440 --> 0:14:03.280 There's a lot that much. I remember for the film. 0:14:03.760 --> 0:14:06.680 Okay, so Madonna was definitely throwing, no matter what position 0:14:06.760 --> 0:14:10.440 she played. No, but it unfortunately did not become the 0:14:10.440 --> 0:14:12.880 basis of the movie as far as I know. Instead, 0:14:13.040 --> 0:14:15.959 it was a place where Calvin laid out an interesting 0:14:17.240 --> 0:14:21.280 sort of story, a possible series of developments that could 0:14:21.320 --> 0:14:25.800 have led to the development of language via the stepping 0:14:25.840 --> 0:14:30.760 stone of capacity for throwing. So the story goes like this, 0:14:31.760 --> 0:14:36.640 lateralization evolved for one handed throwing with the right hand, 0:14:36.800 --> 0:14:41.680 specifically so that parents, typically mothers, could cradle an infant 0:14:41.840 --> 0:14:45.520 on their left side and then they'd be free to 0:14:45.760 --> 0:14:49.360 throw with the right hand if they needed to. So, 0:14:49.440 --> 0:14:51.800 I mean, obviously things like this are hard to prove 0:14:51.920 --> 0:14:55.080 for sure, but that is an interesting idea because I 0:14:55.160 --> 0:14:59.040 started thinking about how I recently became a father, and 0:14:59.240 --> 0:15:02.840 without thinking about it at all, I pretty much always 0:15:02.880 --> 0:15:05.720 when I hold my baby, hold her on the left 0:15:05.760 --> 0:15:08.640 side of my torso, and so if she like falls 0:15:08.680 --> 0:15:11.560 asleep against me, her head is going to be on 0:15:11.680 --> 0:15:15.320 the left side of my chest and from my point 0:15:15.320 --> 0:15:18.000 of view, which is also the side where the heartbeat 0:15:18.080 --> 0:15:20.880 is closer. I never planned it that way, that that 0:15:21.040 --> 0:15:24.240 just sort of happened, and I was talking to my 0:15:24.320 --> 0:15:27.080 wife and she said, yeah, most often she's on the 0:15:27.120 --> 0:15:29.920 left side there too, So I don't know that that's 0:15:30.000 --> 0:15:32.200 kind of interesting. I mean, it could be totally unrelated, 0:15:32.200 --> 0:15:32.720 but I don't know. 0:15:33.640 --> 0:15:36.360 Yeah, yeah, yeah, I would always scoop up on the 0:15:36.440 --> 0:15:38.720 left side as well. My son is now I think 0:15:38.760 --> 0:15:42.240 finally too big for me to do that without seriously 0:15:42.240 --> 0:15:43.000 injuring myself. 0:15:43.040 --> 0:15:46.040 But yes, and I guess at a certain point you 0:15:46.120 --> 0:15:49.320 become less desiring of the heartbeat sound that like maybe 0:15:49.360 --> 0:15:52.360 loses some of the power it has over really young infants. 0:15:52.920 --> 0:15:55.280 Yeah, I don't know. I guess it varies from child 0:15:55.280 --> 0:15:58.440 to child, depends on how big they get and at 0:15:58.480 --> 0:15:59.920 what point they want that distance. 0:16:10.000 --> 0:16:11.960 Okay, well, so it's hard to know for sure if 0:16:11.960 --> 0:16:13.920 the need to scoop a child and hold them on 0:16:13.960 --> 0:16:15.960 the left side of the body, close to the heartbeat 0:16:16.080 --> 0:16:19.760 is the real reason driving brain lateralization. I find it 0:16:19.840 --> 0:16:23.520 more compelling than some other hypotheses that seemed to be 0:16:24.400 --> 0:16:27.160 on offer at the time, one that cited I was 0:16:27.200 --> 0:16:30.200 reading a review of this book by Calvin that cited 0:16:30.200 --> 0:16:35.120 a previous hypothesis that the right handedness evolved because men 0:16:35.240 --> 0:16:39.160 in battle I guess prehistoric battle needed to hold a 0:16:39.240 --> 0:16:42.320 shield above their above their heart on the left side. 0:16:42.400 --> 0:16:43.720 I was like, I get out of here. 0:16:45.800 --> 0:16:49.680 This discussion reminds me of a painting, an eighteen eighty 0:16:49.720 --> 0:16:51.520 eight painting that I hadn't thought of in a bit, 0:16:52.080 --> 0:16:54.120 I believe what if The title of this piece is 0:16:54.160 --> 0:17:01.680 Two Mothers by Leon Maxim of Favre. I'm pronouncing that correctly. 0:17:01.720 --> 0:17:05.040 It's f A I v R. But it's a pretty 0:17:05.320 --> 0:17:09.600 stunning piece in which we see this vision of a 0:17:10.119 --> 0:17:13.800 of a prehistoric mother with very modern touches to it. 0:17:14.400 --> 0:17:17.080 But she's standing here in some sort of a you know, 0:17:17.119 --> 0:17:21.760 a hide garment, and she has this heavy looking infant 0:17:22.000 --> 0:17:25.480 in her left arm, and then there's another child sort 0:17:25.480 --> 0:17:28.439 of hanging on to her left arm. In her right hand, 0:17:28.680 --> 0:17:32.880 she has uh like some sort of a stone weapon, 0:17:33.400 --> 0:17:37.960 like a wooden half with a with a stone blade, 0:17:38.000 --> 0:17:41.000 some sort of like you know, primitive acts or club. 0:17:41.440 --> 0:17:44.520 And she's staring back into the shadows behind her with 0:17:44.640 --> 0:17:47.560 there's this kind of like cave environment, and there's clearly 0:17:47.800 --> 0:17:51.840 an animal lurking there or an animal emerging from the shadows. 0:17:51.840 --> 0:17:53.960 And I think this is supposed to be the other mother, 0:17:54.320 --> 0:17:56.720 the mother that is hunting her. And I have no 0:17:56.800 --> 0:17:59.959 idea of this. This this piece has has any connection 0:18:00.040 --> 0:18:01.840 what we're talking about here, But it is interesting that 0:18:01.920 --> 0:18:07.080 we do see left arm cradling children, right arm brandishing 0:18:07.080 --> 0:18:10.000 a weapon to protect those children against some threat. 0:18:10.720 --> 0:18:12.399 It is a kind of beautiful painting. Yeah. 0:18:12.520 --> 0:18:15.600 Yeah, her hair is perfect too, like this mom's really 0:18:15.600 --> 0:18:19.280 got it together, perfect hair, protecting the children, ready to 0:18:19.560 --> 0:18:22.480 brain a panther with some sort of a stone weapon. 0:18:23.240 --> 0:18:27.600 Anyway, whatever the cause of the right hand lateralization for 0:18:28.000 --> 0:18:33.520 sequential motor control in throwing, The hypothesis goes on from 0:18:33.560 --> 0:18:37.920 here to suggest that sequential motor control regions that made 0:18:37.960 --> 0:18:41.399 us so good at tossing a stone with one hand 0:18:41.840 --> 0:18:47.720 were eventually commondeered by selection pressure for communication and shifted 0:18:47.760 --> 0:18:50.840 to a different kind of sequential motor control, which was 0:18:51.080 --> 0:18:54.320 language production. Now, when we think of language production, we 0:18:54.359 --> 0:18:57.280 think of speech, and that could be the case. I 0:18:57.400 --> 0:19:00.760 think Calvin argued for a transitional state where the original 0:19:00.800 --> 0:19:04.560 language was more gesture based, like gesturing with the hands maybe, 0:19:05.400 --> 0:19:10.000 which would have then transitioned into speech production with the mouth. Again, 0:19:10.080 --> 0:19:12.520 like many things here, that's not something we know for sure, 0:19:12.560 --> 0:19:14.800 so we're in very speculative territory. But I do find 0:19:14.840 --> 0:19:18.199 this really interesting. So again, if there's anything to this story, 0:19:18.520 --> 0:19:21.040 it would go that for some reason, there is an 0:19:21.080 --> 0:19:26.000 original right hand left brain motor lateralization for the majority 0:19:26.040 --> 0:19:29.840 of the population for throwing objects. Human ancestors get really 0:19:29.880 --> 0:19:32.240 good at throwing with that one hand, maybe cradling a 0:19:32.240 --> 0:19:35.560 baby in the other arm or doing something else. And 0:19:35.600 --> 0:19:39.600 then you could argue that the lateralization for precise sequential 0:19:39.600 --> 0:19:44.000 motor activity and the left brain to power throwing eventually 0:19:44.040 --> 0:19:48.240 provides the neurological scaffolding for the left brain's capacity for 0:19:48.400 --> 0:19:52.840 language and speech. Now, what was the actual experiment in 0:19:53.040 --> 0:19:56.240 this study, Well, it was looking at our closest primate 0:19:56.280 --> 0:20:00.280 relatives to see if they could provide any insight on 0:20:00.720 --> 0:20:02.280 what might have been going on in the brains of 0:20:02.400 --> 0:20:07.120 very distant human ancestors. So they were looking at chimpanzees. Now, again, 0:20:07.200 --> 0:20:10.600 chimpanzees don't throw nearly as well or as often as 0:20:10.640 --> 0:20:15.760 we do, but some throw sometimes, So what if anything 0:20:15.920 --> 0:20:19.639 is different in the brains of chimpanzees that reliably throw 0:20:20.000 --> 0:20:23.639 versus those that don't. Specifically, the authors looked at the 0:20:23.760 --> 0:20:27.320 ratio of two different types of brain tissue, white matter 0:20:27.400 --> 0:20:31.080 and gray matter in the areas of chimpanzee brains that 0:20:31.119 --> 0:20:34.000 would be most similar to the areas of the human 0:20:34.040 --> 0:20:37.600 brain involved in motor control for throwing and for speech. 0:20:38.040 --> 0:20:41.119 And this would be quote the homologue to Broca's area. 0:20:41.160 --> 0:20:44.520 I remember again Broker's areas involved in speech production in humans. 0:20:45.119 --> 0:20:47.320 And then they also say as well as the motor 0:20:47.480 --> 0:20:51.480 hand area of the precentral gyrus termed the knob, K 0:20:51.640 --> 0:20:54.600 and OB. And what they found was that in both 0:20:54.640 --> 0:20:58.000 of these areas, in the chimpanzee equivalent of Broker's area 0:20:58.080 --> 0:21:01.000 and in the knob. The ratio of white matter to 0:21:01.160 --> 0:21:06.000 gray matter was higher in chimpanzees that throw versus those 0:21:06.040 --> 0:21:10.840 that don't. Also quote, we further found that asymmetries in 0:21:10.920 --> 0:21:14.800 white matter within both brain regions were larger in the 0:21:14.840 --> 0:21:20.679 hemisphere contralateral to the chimpanzee's preferred throwing hand. So what 0:21:20.680 --> 0:21:22.920 they're saying is it's not just that the ratio of 0:21:22.960 --> 0:21:25.440 white matter was higher in these regions on both sides 0:21:25.480 --> 0:21:28.679 of the brain. It's that whichever hand the chimpanzee liked 0:21:28.720 --> 0:21:32.880 to throw with those particular regions had a higher proportion 0:21:33.000 --> 0:21:37.399 of white matter on the opposite side of the brain. Also, 0:21:37.480 --> 0:21:40.960 they assessed the chimpanzees in this study with what is 0:21:41.080 --> 0:21:46.040 called a Primate Cognition Test BATTERY or pct B, which is, 0:21:46.480 --> 0:21:50.680 you know, a sort of an SAT for chimpanzees, standard 0:21:50.840 --> 0:21:54.480 tests on all kinds of mental abilities, you know, tons 0:21:54.520 --> 0:22:00.480 of things, spatial memory, causality, inference, tool property, recognition, gaze following, 0:22:00.640 --> 0:22:03.200 and so forth. And they were looking at, well, are 0:22:03.200 --> 0:22:06.840 there any differences between apes that throw and apes that 0:22:07.040 --> 0:22:12.040 don't throw? And out of this entire test battery generally 0:22:12.119 --> 0:22:15.840 not generally, there were no cognitive differences except in one area. 0:22:16.000 --> 0:22:19.920 There was only one aptitude where there was a significant difference, 0:22:20.400 --> 0:22:23.760 and it was that researchers found chimpanzees that were more 0:22:23.760 --> 0:22:29.159 inclined to throw were also better at social communication. So 0:22:29.240 --> 0:22:32.520 the author's right quote. These results suggest that chimpanzees that 0:22:32.600 --> 0:22:37.280 have learned to throw have developed greater cortical connectivity that's 0:22:37.400 --> 0:22:40.840 correlating with the white matter between the primary motor cortex 0:22:41.240 --> 0:22:45.200 and the Broca's area. Homologue, it is suggested that during 0:22:45.280 --> 0:22:49.320 hominine evolution, after the split between lines leading to chimpanzees 0:22:49.359 --> 0:22:53.400 and humans, there was intense selection on increased motor skills 0:22:53.440 --> 0:22:57.440 associated with throwing, and that this potentially formed the foundation 0:22:57.640 --> 0:23:02.600 for left hemisphere specialization associated with language and speech found 0:23:02.680 --> 0:23:06.399 in modern humans. So this is another case where I 0:23:06.440 --> 0:23:08.560 think this is far from proven. We would need much 0:23:08.600 --> 0:23:12.640 more robust evidence before you could endorse this specific evolutionary 0:23:12.640 --> 0:23:17.399 story as likely. But I find this very intriguing and 0:23:17.520 --> 0:23:20.080 it does seem possible to me that the capacity for 0:23:20.240 --> 0:23:23.840 throwing gave rise to the capacity for language. 0:23:24.920 --> 0:23:28.679 So ape throws the bone, the bone spins around the 0:23:28.720 --> 0:23:33.080 bone becomes a space station, just as Kubrick promised us. 0:23:33.200 --> 0:23:34.280 Yeah, I didn't think about that. 0:23:34.359 --> 0:23:37.280 Yeah, I want to get back into this idea of 0:23:37.720 --> 0:23:42.600 early humans, especially throwing stones as weapons and throwing other 0:23:42.680 --> 0:23:45.200 things as weapons. You know, as we discussed in the 0:23:45.240 --> 0:23:48.000 last episode, we talked about some of the ideas concerning 0:23:48.000 --> 0:23:51.760 the development of ranged weapon technology and prehistoric humans. This 0:23:51.880 --> 0:23:54.600 idea that what first begins as a way of engaging 0:23:54.680 --> 0:23:59.040 in agonistic communication could transform into just a way of 0:23:59.240 --> 0:24:03.000 physically sin a message to another species via projectile. But 0:24:03.040 --> 0:24:05.760 then eventually that begins to get into this way to 0:24:05.800 --> 0:24:09.720 manipulate their behavior at range, especially in the case of 0:24:09.760 --> 0:24:12.639