WEBVTT 00:00:00.000 --> 00:00:03.419 Okay, so let's unpack this. Ivan Pavlov. You 00:00:03.419 --> 00:00:06.200 hear that name, and I mean... Instantly a bell 00:00:06.200 --> 00:00:08.820 rings. Literally. Literally a bell rings or maybe 00:00:08.820 --> 00:00:11.460 a metronome ticks. And you just get this image 00:00:11.460 --> 00:00:14.160 of a dog drooling on cue. Right. It's almost 00:00:14.160 --> 00:00:16.879 a caricature. He's probably the single most famous 00:00:16.879 --> 00:00:19.300 scientist who's been reduced entirely to one 00:00:19.300 --> 00:00:22.739 single pop culture experiment. The ultimate reduction 00:00:22.739 --> 00:00:24.620 is trap. You know, the general understanding 00:00:24.620 --> 00:00:28.079 of Pavlov is just stuck somewhere between a cartoon 00:00:28.079 --> 00:00:31.160 of a salivating dog and maybe a page in a Psych 00:00:31.160 --> 00:00:33.659 101 textbook. It really is. But when you actually 00:00:33.659 --> 00:00:36.679 dive into this. I mean, the historical record 00:00:36.679 --> 00:00:40.079 of his career, you find this profound, almost 00:00:40.079 --> 00:00:42.799 unbelievable duality in his professional life. 00:00:42.920 --> 00:00:44.780 A duality that starts with him being a master 00:00:44.780 --> 00:00:47.799 physiologist first, operating czarist, and then 00:00:47.799 --> 00:00:50.880 early Soviet Russia. And what stands out immediately, 00:00:51.100 --> 00:00:52.840 and this is the insight we really want to drill 00:00:52.840 --> 00:00:55.140 into for you today, is that his Nobel Prize. 00:00:55.320 --> 00:00:57.799 Yeah. It had absolutely nothing to do with bells 00:00:57.799 --> 00:01:00.539 or dogs or conditioning. Not a thing. He won 00:01:00.539 --> 00:01:03.280 it for completely transforming our surgical understanding 00:01:03.280 --> 00:01:06.299 of the digestive system. And that's our mission 00:01:06.299 --> 00:01:08.939 for this deep dive. Moving beyond the conditional 00:01:08.939 --> 00:01:11.560 reflex to the revolutionary scientists behind 00:01:11.560 --> 00:01:14.560 it all. We're going to explore the vast kind 00:01:14.560 --> 00:01:17.879 of complex career of a man who was first and 00:01:17.879 --> 00:01:21.439 foremost a surgical genius and a pioneer in physiological 00:01:21.439 --> 00:01:24.319 methodology. We're diving into his whole journey 00:01:24.319 --> 00:01:26.640 from this strict religious seminary background 00:01:26.640 --> 00:01:29.239 all the way to becoming the first Russian Nobel 00:01:29.239 --> 00:01:31.739 laureate. And we'll focus on the specific, really 00:01:31.739 --> 00:01:34.459 complex details of his surgical innovations and 00:01:34.459 --> 00:01:36.859 his surprisingly turbulent political life under 00:01:36.859 --> 00:01:39.560 the Soviet state, where he was somehow both a 00:01:39.560 --> 00:01:42.120 favored son and a very open critic. And here's 00:01:42.120 --> 00:01:44.420 where it gets really interesting for me. That 00:01:44.420 --> 00:01:47.780 meticulous nature, that absolute drive for scientific 00:01:47.780 --> 00:01:51.099 purity and just measuring things, that is precisely 00:01:51.099 --> 00:01:53.859 what led him to his most famous yet completely 00:01:53.859 --> 00:01:56.920 unplanned discovery in psychology. He was actually 00:01:56.920 --> 00:01:59.640 trying to eliminate a variable. And instead, 00:01:59.840 --> 00:02:03.120 he just discovered a whole new field of study. 00:02:03.219 --> 00:02:05.019 An incredible story. So let's start at the very 00:02:05.019 --> 00:02:08.379 beginning, in Ryazan, Russia. Because his affirmative 00:02:08.379 --> 00:02:11.879 years, they gave absolutely no indication he 00:02:11.879 --> 00:02:13.699 would end up changing the whole landscape of 00:02:13.699 --> 00:02:16.240 scientific psychology and medicine. So when we 00:02:16.240 --> 00:02:19.599 look at his birth year, 1849, you have to picture 00:02:19.599 --> 00:02:22.650 the heart. of Tsarist Russia. It's a society 00:02:22.650 --> 00:02:25.030 deeply rooted in tradition and, of course, the 00:02:25.030 --> 00:02:28.270 Orthodox Church. Right. And Ivan Petrovich Pavlov 00:02:28.270 --> 00:02:31.270 was the first of 10 children born to a Russian 00:02:31.270 --> 00:02:34.289 Orthodox priest, Peter Dmitrovich Pavlov. 10 00:02:34.289 --> 00:02:38.050 children? 10. And his wife, Varvara Ivanovna 00:02:38.050 --> 00:02:41.400 Uspenskaya, was, you know... a diligent homemaker. 00:02:41.520 --> 00:02:43.879 You can just imagine the atmosphere of a large 00:02:43.879 --> 00:02:45.879 religious household. A lot of structure, a lot 00:02:45.879 --> 00:02:49.000 of faith. Exactly. Young Ivan willingly participated 00:02:49.000 --> 00:02:51.120 in house duties, things like gardening, doing 00:02:51.120 --> 00:02:53.099 the dishes, caring for his younger siblings. 00:02:53.360 --> 00:02:55.759 It was just a life of structure. It sounds like 00:02:55.759 --> 00:02:57.840 the kind of traditional pious upbringing that's 00:02:57.840 --> 00:03:00.000 designed to produce the next generation of clergy, 00:03:00.219 --> 00:03:02.500 which, you know, makes his eventual pivot to 00:03:02.500 --> 00:03:04.520 radical science all the more dramatic. It does. 00:03:04.620 --> 00:03:07.020 And his early life was also marked by a pretty 00:03:07.020 --> 00:03:08.919 serious setback that delayed his trajectory. 00:03:09.500 --> 00:03:12.020 Yeah, he was able to read by seven, but he didn't 00:03:12.020 --> 00:03:13.840 actually start formal schooling until he was 00:03:13.840 --> 00:03:16.439 11 years old. And that delay was because of a 00:03:16.439 --> 00:03:19.300 really consequential childhood injury. He fell 00:03:19.300 --> 00:03:22.780 from a high wall onto a stone pavement and sustained 00:03:22.780 --> 00:03:25.900 some very serious injuries. Wow. It required 00:03:25.900 --> 00:03:28.580 a long recovery time, and it kind of illustrates 00:03:28.580 --> 00:03:31.120 the fragility of life and, you know, the limitations 00:03:31.120 --> 00:03:33.659 of medicine back in the 19th century. You have 00:03:33.659 --> 00:03:35.860 to wonder if that experience subconsciously planted 00:03:35.860 --> 00:03:38.120 the seeds of a deep interest in how the body 00:03:38.120 --> 00:03:40.819 works, how it recovers. It's very possible. So 00:03:40.819 --> 00:03:43.400 he initially attended the Ryazan Church School 00:03:43.400 --> 00:03:46.240 and then the local theological seminary, which 00:03:46.240 --> 00:03:48.800 was strictly the expected path for a priest's 00:03:48.800 --> 00:03:52.330 son. But the scientific and... Progressive seeds 00:03:52.330 --> 00:03:54.789 were already being planted through literature 00:03:54.789 --> 00:03:57.629 and intellectual exchange. Yes. This is where 00:03:57.629 --> 00:04:00.729 he encounters the ideas that completely rerouted 00:04:00.729 --> 00:04:03.210 his entire life, a real intellectual rupture. 00:04:03.229 --> 00:04:05.689 He was inspired by the progressive materialist 00:04:05.689 --> 00:04:09.379 philosophy of this literary critic. Dmitry Pisarev. 00:04:09.419 --> 00:04:11.960 Pisarev was critical for that whole generation 00:04:11.960 --> 00:04:14.860 of Russian intellectuals. His ideas promoted 00:04:14.860 --> 00:04:18.300 radical social reform and, really importantly 00:04:18.300 --> 00:04:21.319 for Pavlov, a skeptical approach to traditional 00:04:21.319 --> 00:04:23.959 dogma. Emphasizing science and observation as 00:04:23.959 --> 00:04:27.240 the only path to truth. Exactly. That gave Pavlov 00:04:27.240 --> 00:04:30.060 the intellectual rationale he needed to abandon 00:04:30.060 --> 00:04:32.319 his religious training. And then there was his 00:04:32.319 --> 00:04:35.139 scientific hero, the physiologist Ivan Sekhanov. 00:04:35.259 --> 00:04:38.920 Ah, yes. A man Pavlov would later revere. He 00:04:38.920 --> 00:04:40.939 even called him the father of Russian physiology. 00:04:41.500 --> 00:04:44.180 So what was Sekunov's big idea? Sekunov's work 00:04:44.180 --> 00:04:47.040 was all about reflexology. He proposed that even 00:04:47.040 --> 00:04:49.500 complex psychological phenomena could be explained 00:04:49.500 --> 00:04:51.720 through physiological reflexes, particularly 00:04:51.720 --> 00:04:54.829 those that start in the brain. Okay, so for Pavlov, 00:04:54.870 --> 00:04:56.810 who's already leaning toward empirical truth 00:04:56.810 --> 00:04:59.769 because of Pisarev, Sekhonov provides the perfect 00:04:59.769 --> 00:05:02.589 scientific framework. The perfect one. The belief 00:05:02.589 --> 00:05:05.110 that the nervous system was the key to unlocking 00:05:05.110 --> 00:05:08.470 all of organic life. So in 1870, at 21 years 00:05:08.470 --> 00:05:11.170 old, he makes this monumental shift. He just 00:05:11.170 --> 00:05:13.490 abandons his religious career without even graduating 00:05:13.490 --> 00:05:15.990 from the seminary. And devotes his life entirely 00:05:15.990 --> 00:05:18.449 to natural science, enrolling in the physics 00:05:18.449 --> 00:05:20.170 and mathematics department at the University 00:05:20.170 --> 00:05:22.319 of St. Petersburg. That must have taken immense 00:05:22.319 --> 00:05:25.300 personal courage. I mean, given his family's 00:05:25.300 --> 00:05:28.360 position as clergy. It absolutely did. And his 00:05:28.360 --> 00:05:30.839 motivation wasn't really career ambition in the 00:05:30.839 --> 00:05:34.040 way we think of it. It was this inherent driving 00:05:34.040 --> 00:05:36.740 force. He called it the instinct for research. 00:05:37.000 --> 00:05:39.620 He wasn't pursuing wealth or status. He was just 00:05:39.620 --> 00:05:42.439 pursuing knowledge. And he didn't waste any time. 00:05:42.829 --> 00:05:45.170 We see immediate success in his research track 00:05:45.170 --> 00:05:47.370 while he's still an undergraduate. That's right. 00:05:47.470 --> 00:05:49.990 In his fourth year, he won a prestigious university 00:05:49.990 --> 00:05:52.769 award for his research on the physiology of the 00:05:52.769 --> 00:05:55.829 nerves of the pancreas. That's a huge early validation, 00:05:56.069 --> 00:05:58.290 like a sign saying you're on the right path. 00:05:58.629 --> 00:06:01.209 It really was. And it gave him the momentum he 00:06:01.209 --> 00:06:03.990 needed to dive into medicine proper. After he 00:06:03.990 --> 00:06:05.870 got his degree of candidate of natural sciences 00:06:05.870 --> 00:06:09.430 in 1875, he went on to the Imperial Academy of 00:06:09.430 --> 00:06:11.870 Medical Surgery. And he spent two intensive years 00:06:11.870 --> 00:06:14.529 just investigating the circulatory system for 00:06:14.529 --> 00:06:16.810 his medical dissertation, so his interests were 00:06:16.810 --> 00:06:19.329 already firmly rooted in the body's involuntary 00:06:19.329 --> 00:06:22.250 systems. He was also attracting powerful mentors. 00:06:22.629 --> 00:06:25.709 He worked with Elias von Sion and later the renowned 00:06:25.709 --> 00:06:28.689 clinician Professor Sergei Botkin. Botkin was 00:06:28.689 --> 00:06:31.990 clearly impressed by Pavlov's rigor. He invited 00:06:31.990 --> 00:06:34.209 him to be the chief of the physiological laboratory 00:06:34.209 --> 00:06:37.300 at his clinic. That whole trajectory led him 00:06:37.300 --> 00:06:39.399 to graduate from the Medical Military Academy 00:06:39.399 --> 00:06:43.300 in 1879, winning a gold medal for his research. 00:06:43.560 --> 00:06:46.639 And the culmination of this early period came 00:06:46.639 --> 00:06:50.759 in 1883 with his doctor's thesis. On the centrifugal 00:06:50.759 --> 00:06:53.060 nerves of the heart. Yes, and that thesis was 00:06:53.060 --> 00:06:55.399 foundational because it introduced one of his 00:06:55.399 --> 00:06:57.779 most important early theoretical contributions. 00:06:58.379 --> 00:07:01.399 Okay, so let's pause on that contribution. The 00:07:01.399 --> 00:07:03.439 basic principles of the trophic function of the 00:07:03.439 --> 00:07:05.079 nervous system. That's a term we need to define. 00:07:05.069 --> 00:07:07.009 find clearly because it really sets the stage 00:07:07.009 --> 00:07:09.550 for everything he did later with digestion and, 00:07:09.629 --> 00:07:12.850 well, conditioning. Absolutely. So the nervous 00:07:12.850 --> 00:07:15.029 system had long been understood to govern movement 00:07:15.029 --> 00:07:17.829 and immediate reflexes, what we might call action 00:07:17.829 --> 00:07:19.709 commands. Right, like pulling your hand away 00:07:19.709 --> 00:07:22.649 from a hot stove. Exactly. But the trophic function 00:07:22.649 --> 00:07:25.569 is much subtler. The word trophic comes from 00:07:25.569 --> 00:07:28.389 the Greek word trophos, which means feeder or 00:07:28.389 --> 00:07:30.949 nourisher. So how did Pavlov define it? What 00:07:30.949 --> 00:07:33.100 was he proposing? He was proposing that the nervous 00:07:33.100 --> 00:07:36.180 system had a regulatory function that went way 00:07:36.180 --> 00:07:39.040 beyond immediate reaction. It actually influenced 00:07:39.040 --> 00:07:41.199 the fundamental health, the growth, the nutrition, 00:07:41.319 --> 00:07:44.240 and the structure of organs and tissues. So think 00:07:44.240 --> 00:07:46.339 of the nervous system not just as the accelerator 00:07:46.339 --> 00:07:48.160 and the brake. But as the engine maintenance 00:07:48.160 --> 00:07:50.920 light, the oil pressure gauge, and the fuel mixture 00:07:50.920 --> 00:07:53.800 control all rolled into one. It's constantly 00:07:53.800 --> 00:07:56.759 regulating the internal metabolic state of the 00:07:56.759 --> 00:07:59.199 tissue itself. That significantly changes how 00:07:59.199 --> 00:08:01.620 we view the nervous system's role. It's not just 00:08:01.620 --> 00:08:03.939 about signal transmission anymore. No, it's about 00:08:03.939 --> 00:08:06.980 long -term biological maintenance. So how did 00:08:06.980 --> 00:08:09.579 proving this change the scientific conversation 00:08:09.579 --> 00:08:12.480 at the time? Well, it suggested that nervous 00:08:12.480 --> 00:08:15.279 disorders could have profound systemic effects 00:08:15.279 --> 00:08:18.220 on the body's actual structure and health, not 00:08:18.220 --> 00:08:21.199 just its immediate movement or feeling. And his 00:08:21.199 --> 00:08:23.139 collaboration with the Botkin Clinic during this 00:08:23.139 --> 00:08:25.639 period, it provided solid empirical evidence 00:08:25.639 --> 00:08:28.279 for a basic pattern in how reflexes regulate 00:08:28.279 --> 00:08:31.980 the circulatory organs. mapping the entire involuntary 00:08:31.980 --> 00:08:34.700 system with this incredible precision, and that 00:08:34.700 --> 00:08:38.620 set the stage for his major breakthrough. So 00:08:38.620 --> 00:08:40.620 his foundational work on the autonomic system, 00:08:40.740 --> 00:08:43.860 it demanded exposure to the best European techniques. 00:08:44.039 --> 00:08:47.700 It did. From 1884 to 1886, he studied in Germany. 00:08:47.779 --> 00:08:50.940 He was in Leipzig with Carl Lidwig, who was a 00:08:50.940 --> 00:08:53.720 giant in physiology, and then in Breslau with 00:08:53.720 --> 00:08:56.019 Rudolf Heidenhain. And Heidenhain was already 00:08:56.019 --> 00:08:58.860 studying digestion using an exteriorized section 00:08:58.860 --> 00:09:01.230 of the stomach. That European apprenticeship 00:09:01.230 --> 00:09:04.350 was absolutely critical. It showed Pavlov the 00:09:04.350 --> 00:09:06.990 cutting edge of surgical physiology, but also, 00:09:07.129 --> 00:09:09.710 and this is key, the methodological limitations 00:09:09.710 --> 00:09:12.490 of the existing techniques. Heidenhain's method 00:09:12.490 --> 00:09:15.230 was good. But it was flawed. It was flawed because 00:09:15.230 --> 00:09:18.149 the isolated stomach section, it behaved abnormally. 00:09:18.149 --> 00:09:20.529 And Pavlov, with his background in the trophic 00:09:20.529 --> 00:09:23.909 nerve function, he realized why it behaved abnormally. 00:09:23.929 --> 00:09:25.210 And here's where it gets really fascinating, 00:09:25.370 --> 00:09:27.049 the part that actually won him the Nobel. Yeah. 00:09:27.129 --> 00:09:29.090 The surgical innovation that gave rise to the 00:09:29.090 --> 00:09:31.490 Pavlov pouch. You mentioned the organ behaved 00:09:31.490 --> 00:09:34.690 abnormally after Heidenhain surgery. What was 00:09:34.690 --> 00:09:37.470 the massive technical challenge that Pavlov overcame? 00:09:37.799 --> 00:09:39.700 The challenge was maintaining the physiological 00:09:39.700 --> 00:09:43.220 normalcy of the subject, specifically the structural 00:09:43.220 --> 00:09:45.419 and functional integrity of the stomach tissue 00:09:45.419 --> 00:09:48.539 being studied. When Heidenhain isolated a section 00:09:48.539 --> 00:09:51.779 of the stomach to collect pure digestive secretions, 00:09:51.779 --> 00:09:55.399 the surgery often meant severing the vagus nerve 00:09:55.399 --> 00:09:58.360 supply to that isolated pouch. So the pouch was 00:09:58.360 --> 00:10:00.299 no longer under the control of the central nervous 00:10:00.299 --> 00:10:03.019 system. Precisely. And because the central nervous 00:10:03.019 --> 00:10:06.159 system via that vagus nerve controls the rate 00:10:06.159 --> 00:10:08.940 and the composition of gastric juices, severing 00:10:08.940 --> 00:10:10.879 that connection meant any results you gathered 00:10:10.879 --> 00:10:13.679 from the pouch were physiologically unreliable. 00:10:13.759 --> 00:10:15.440 It was a failure to account for that trophic 00:10:15.440 --> 00:10:18.090 function he was so interested in. Exactly. Pavlov 00:10:18.090 --> 00:10:20.990 perfected the exteriorization technique by overcoming 00:10:20.990 --> 00:10:24.009 this problem. He engineered a specific surgical 00:10:24.009 --> 00:10:26.570 procedure that created what's now called the 00:10:26.570 --> 00:10:29.590 Pavlov pouch, an isolated, smaller stomach section, 00:10:29.809 --> 00:10:32.429 while meticulously maintaining the external nerve 00:10:32.429 --> 00:10:34.950 supply. Especially branches of the vagus nerve. 00:10:35.210 --> 00:10:37.870 Especially the vagus nerve. And this allowed 00:10:37.870 --> 00:10:40.549 him to study the digestive process under far 00:10:40.549 --> 00:10:43.529 more natural, regulated conditions. That just 00:10:43.529 --> 00:10:46.919 sounds like genius -level surgical mastery. How 00:10:46.919 --> 00:10:49.039 difficult was it mechanically to perform that 00:10:49.039 --> 00:10:51.940 procedure without causing nerve damage or infection? 00:10:52.200 --> 00:10:54.539 Oh, it was incredibly difficult. The vagus nerve 00:10:54.539 --> 00:10:56.860 is a very delicate structure, and the surgery 00:10:56.860 --> 00:10:59.399 required separating a small portion of the stomach 00:10:59.399 --> 00:11:02.559 lining while preserving all the vascular and, 00:11:02.580 --> 00:11:04.740 most critically, the nervous connections. It 00:11:04.740 --> 00:11:06.700 must have required a long recovery for the animals. 00:11:06.840 --> 00:11:09.700 Days, weeks, sometimes even months of recovery, 00:11:09.840 --> 00:11:12.519 which illustrates Pavlov's dedication to long 00:11:12.519 --> 00:11:15.759 -term care and observation. This technical feat... 00:11:15.820 --> 00:11:17.899 was really the foundation for his entire reputation. 00:11:18.379 --> 00:11:20.860 And that surgical skill allowed for a monumental 00:11:20.860 --> 00:11:24.019 shift in scientific methodology, the shift to 00:11:24.019 --> 00:11:26.960 chronic experimentation. Yes. I understand previous 00:11:26.960 --> 00:11:30.279 experiments were acute, meaning they involved 00:11:30.279 --> 00:11:32.580 a vivisection, which resulted in the death of 00:11:32.580 --> 00:11:34.389 the animal during the procedure. That's a key 00:11:34.389 --> 00:11:36.610 distinction, and it reflects Pavlov's commitment 00:11:36.610 --> 00:11:39.990 to real -world physiology. Acute experiments 00:11:39.990 --> 00:11:42.610 could only observe immediate reactions or post 00:11:42.610 --> 00:11:45.090 -mortem structure. You were essentially studying 00:11:45.090 --> 00:11:47.889 a system in shock, not a system functioning normally. 00:11:48.129 --> 00:11:51.190 But Pavlov insisted on chronic experiments. These 00:11:51.190 --> 00:11:53.470 long -term studies where the canines were not 00:11:53.470 --> 00:11:55.850 only kept alive, but were kept healthy, treated 00:11:55.850 --> 00:11:59.590 well, and observed repeatedly. Yes, his lab actually 00:11:59.590 --> 00:12:01.950 housed a full -scale kennel for the experimental 00:12:01.950 --> 00:12:04.889 canines, not just a surgical theater. He saw 00:12:04.889 --> 00:12:07.450 these animals as research partners, not disposable 00:12:07.450 --> 00:12:09.970 specimens. Because he recognized that only a 00:12:09.970 --> 00:12:12.529 healthy, relaxed animal could provide valid data 00:12:12.529 --> 00:12:15.350 on normal digestive function. Absolutely. This 00:12:15.350 --> 00:12:17.450 approach dramatically improved the scientific 00:12:17.450 --> 00:12:20.309 validity and, you know, it offered a moral counterpoint 00:12:20.309 --> 00:12:22.710 to the prevailing, often brutal, vivisection 00:12:22.710 --> 00:12:24.909 methods of the time. That makes perfect sense. 00:12:25.110 --> 00:12:27.870 If you are studying how a system works when you 00:12:27.870 --> 00:12:30.409 are healthy and eating a meal, you can't study 00:12:30.409 --> 00:12:32.549 that on an animal that is actively dying on the 00:12:32.549 --> 00:12:35.889 table. Exactly. And his team was so meticulous 00:12:35.889 --> 00:12:38.149 in how they conducted these long term studies. 00:12:38.509 --> 00:12:41.789 They surgically implanted fistulas, these permanent 00:12:41.789 --> 00:12:44.570 openings between organs and external pouches 00:12:44.570 --> 00:12:47.289 to examine contents and secretions. And sometimes 00:12:47.289 --> 00:12:49.470 they went even further. Oh, yeah. The legendary 00:12:49.470 --> 00:12:52.029 sham feeding mechanism. Can you explain that 00:12:52.029 --> 00:12:55.080 specific detail? The sham feeding procedure was 00:12:55.080 --> 00:12:58.860 just pure methodological brilliance. So to study 00:12:58.860 --> 00:13:02.259 the pure secretion of gastric juices that was 00:13:02.259 --> 00:13:04.679 prompted by just the sight or smell of food. 00:13:04.840 --> 00:13:06.580 Without the food actually getting into the stomach. 00:13:06.679 --> 00:13:08.799 Correct. Without the complications of the food 00:13:08.799 --> 00:13:11.080 physically entering the main stomach, they would 00:13:11.080 --> 00:13:13.899 surgically create a separate opening in the esophagus, 00:13:13.980 --> 00:13:16.980 diverting the chewed food outside the body. Wait. 00:13:17.279 --> 00:13:19.559 So the dog would eat, it would enjoy the flavor, 00:13:19.600 --> 00:13:22.019 chew the meat. Everything. But the food would 00:13:22.019 --> 00:13:23.919 never actually enter the stomach. Correct. The 00:13:23.919 --> 00:13:26.220 chewing, the tasting, the swallowing, it all 00:13:26.220 --> 00:13:28.779 provided the immediate nervous signals to the 00:13:28.779 --> 00:13:31.879 stomach, the psychic phase of digestion, without 00:13:31.879 --> 00:13:34.399 the mechanical or chemical stimulation of food 00:13:34.399 --> 00:13:37.100 touching the stomach lining. Which allowed Pavlov 00:13:37.100 --> 00:13:39.700 to isolate the pure nervous control of the digestive 00:13:39.700 --> 00:13:43.210 glands. and prove definitively that the vagus 00:13:43.210 --> 00:13:46.110 nerve played the primary role in initiating digestion, 00:13:46.490 --> 00:13:49.909 based purely on external cues like sight and 00:13:49.909 --> 00:13:53.070 anticipation. Twelve years of this kind of meticulous 00:13:53.070 --> 00:13:55.990 research, the Pavlov pouch, Chronic studies, 00:13:56.309 --> 00:13:59.110 sham feeding it all, culminated in his major 00:13:59.110 --> 00:14:01.210 publication, The Work of the Digestive Glands, 00:14:01.309 --> 00:14:04.429 in 1897. And after four successive nominations 00:14:04.429 --> 00:14:06.669 for the Nobel Prize in Physiology or Medicine, 00:14:06.950 --> 00:14:10.289 he finally won in 1904. That recognition was 00:14:10.289 --> 00:14:12.529 immense. It made him the first Russian Nobel 00:14:12.529 --> 00:14:14.909 laureate. Yes, and the Nobel Committee was very 00:14:14.909 --> 00:14:17.570 specific. They said the award was in recognition 00:14:17.570 --> 00:14:20.990 of his work on the physiology of digestion, through 00:14:20.990 --> 00:14:23.289 which knowledge on vital aspects of the subject 00:14:23.289 --> 00:14:25.929 has been transformed. enlarged. He proved that 00:14:25.929 --> 00:14:28.169 digestion was a finely coordinated reflex arc 00:14:28.169 --> 00:14:30.370 regulated by the nervous system, not just some 00:14:30.370 --> 00:14:33.070 localized chemical process. He literally transformed 00:14:33.070 --> 00:14:36.929 the field. The genius of guts, indeed. He transformed 00:14:36.929 --> 00:14:39.250 medical research by making the animal subject 00:14:39.250 --> 00:14:42.370 an ongoing, dynamic laboratory rather than a 00:14:42.370 --> 00:14:45.509 one -time specimen, all based on a profound understanding 00:14:45.509 --> 00:14:48.809 of nerve function. Now, here's where the world 00:14:48.809 --> 00:14:52.710 shifted. All of this dedication to pure, long 00:14:52.710 --> 00:14:55.309 -term physiological observation, these chronic 00:14:55.309 --> 00:14:58.269 experiments, is what led, almost by accident, 00:14:58.549 --> 00:15:00.889 to his most famous contribution to psychology. 00:15:01.370 --> 00:15:03.889 The happy accident. It occurred because he was 00:15:03.889 --> 00:15:06.250 trying to measure physiological reactions so 00:15:06.250 --> 00:15:08.690 precisely. He's trying to eliminate variables, 00:15:08.889 --> 00:15:11.450 but he encountered a whole new uncontrollable 00:15:11.450 --> 00:15:13.990 variable. What did he observe that was so unexpected? 00:15:14.620 --> 00:15:16.960 He observed what he called psychic secretions. 00:15:17.139 --> 00:15:19.460 During the measurements of saliva and gastric 00:15:19.460 --> 00:15:21.860 juices, he saw that the dogs began to produce 00:15:21.860 --> 00:15:23.899 the digestive fluids before the food was even 00:15:23.899 --> 00:15:26.080 presented. So they weren't reacting to the food 00:15:26.080 --> 00:15:29.059 itself. Not yet. They began salivating the moment 00:15:29.059 --> 00:15:30.960 they saw the laboratory technician who routinely 00:15:30.960 --> 00:15:33.159 fed them, or even when they just heard his approaching 00:15:33.159 --> 00:15:35.980 footsteps. So the organism was anticipating the 00:15:35.980 --> 00:15:39.299 food based on an external cue that had no inherent 00:15:39.299 --> 00:15:43.120 link to nutrition. This... This contamination 00:15:43.120 --> 00:15:46.440 of his pure physiological data must have been 00:15:46.440 --> 00:15:48.639 initially frustrating for such a rigorous scientist. 00:15:48.740 --> 00:15:51.759 It was. But Pavlov was too dedicated to that 00:15:51.759 --> 00:15:54.419 instinct for research to just ignore the phenomenon. 00:15:54.740 --> 00:15:57.220 He realized he had stumbled upon a fundamental 00:15:57.220 --> 00:16:00.220 law of learning. So he shifted his focus. He 00:16:00.220 --> 00:16:03.000 quickly shifted to systematically study how these 00:16:03.000 --> 00:16:05.500 external cues triggered involuntary physiological 00:16:05.500 --> 00:16:09.019 responses. And this led him to develop the concept 00:16:09.019 --> 00:16:11.639 of the conditional reflex. Later known in English. 00:16:11.720 --> 00:16:14.259 as the conditioned reflex or classical conditioning. 00:16:14.500 --> 00:16:17.039 Exactly. And he did this jointly with his assistant, 00:16:17.179 --> 00:16:20.340 Ivan Tolokshinov, around 1901. The core idea, 00:16:20.480 --> 00:16:23.000 which I think we all know in abstract, is that 00:16:23.000 --> 00:16:26.059 if a neutral stimulus, like a sound, is consistently 00:16:26.059 --> 00:16:28.639 presented just before the food, the unconditioned 00:16:28.639 --> 00:16:31.120 stimulus, the organism will eventually associate 00:16:31.120 --> 00:16:33.600 the two. And produce the involuntary physiological 00:16:33.600 --> 00:16:36.139 response to the sound alone. Right. The sound 00:16:36.139 --> 00:16:37.860 becomes the conditional stimulus. The food is 00:16:37.860 --> 00:16:40.600 the unconditional stimulus. And the salivation 00:16:40.600 --> 00:16:43.000 becomes the conditional response when it's prompted 00:16:43.000 --> 00:16:46.320 by just the sound. This showed that higher brain 00:16:46.320 --> 00:16:48.759 centers could reorganize the reflex pathways 00:16:48.759 --> 00:16:51.860 that governed involuntary functions like digestion. 00:16:52.139 --> 00:16:54.659 It was huge. And Filoktunov was actually the 00:16:54.659 --> 00:16:56.519 first to communicate the initial results, right? 00:16:56.580 --> 00:16:59.379 He was. He called the phenomenon a reflex at 00:16:59.379 --> 00:17:01.759 a distance at the Congress of Natural Sciences 00:17:01.759 --> 00:17:05.079 in Helsinki in 1903. But there's a fascinating 00:17:05.079 --> 00:17:07.640 wrinkle in the history here about precedence. 00:17:08.089 --> 00:17:11.490 We often credit Pavlov alone, but there was parallel 00:17:11.490 --> 00:17:14.250 work happening simultaneously in the U .S. This 00:17:14.250 --> 00:17:16.470 brings up an important question of timing and, 00:17:16.529 --> 00:17:18.910 you know, publication impact. Edwin B. Twitmire 00:17:18.910 --> 00:17:21.230 in Philadelphia published similar research in 00:17:21.230 --> 00:17:24.190 1902. A year before Pavlov published his full 00:17:24.190 --> 00:17:26.369 theoretical explanation. A full year before, 00:17:26.490 --> 00:17:28.730 Twitmire demonstrated the conditioning of the 00:17:28.730 --> 00:17:31.650 knee -jerk reflex in humans. So if Twitmire published 00:17:31.650 --> 00:17:34.450 first, why does Pavlov get all the credit for 00:17:34.450 --> 00:17:36.849 establishing classical conditioning as this cornerstone 00:17:36.849 --> 00:17:39.960 of psychology? It largely boils down to the scope 00:17:39.960 --> 00:17:42.529 and the theoretical framework. Twitmire's work 00:17:42.529 --> 00:17:44.809 was localized. He demonstrated a conditioned 00:17:44.809 --> 00:17:47.710 reflex in a specific instance, and it was presented 00:17:47.710 --> 00:17:50.730 during a Ph .D. dissertation defense. It just 00:17:50.730 --> 00:17:53.150 didn't get wide scientific dissemination at the 00:17:53.150 --> 00:17:55.910 time. Whereas Pavlov was a Nobel laureate who 00:17:55.910 --> 00:17:58.170 immediately connected this accidental insight 00:17:58.170 --> 00:18:01.349 to his massive existing framework of nervous 00:18:01.349 --> 00:18:03.730 system activity. Exactly. He didn't just notice 00:18:03.730 --> 00:18:06.150 a dog grueling. He formulated a comprehensive 00:18:06.150 --> 00:18:08.890 theory of how the brain creates these systematic 00:18:08.890 --> 00:18:11.180 temporary connections. Which he fooled. Fully 00:18:11.180 --> 00:18:13.940 explained at the 14th International Medical Congress 00:18:13.940 --> 00:18:17.680 in Madrid in 1903 in a paper titled The Experimental 00:18:17.680 --> 00:18:20.099 Psychology and Psychopathology of Animals. Right. 00:18:20.200 --> 00:18:23.220 He established the broad principles. Acquisition. 00:18:23.589 --> 00:18:26.329 Extinction, spontaneous recovery, generalization, 00:18:26.609 --> 00:18:29.269 all the fundamental mechanisms that govern associative 00:18:29.269 --> 00:18:32.390 learning. His comprehensive physiological approach 00:18:32.390 --> 00:18:34.549 gave the finding a weight and an intellectual 00:18:34.549 --> 00:18:37.490 momentum that Twitmire's more isolated observation 00:18:37.490 --> 00:18:39.910 just didn't have at the time. And yet the single 00:18:39.910 --> 00:18:42.210 most famous image associated with him, the bell, 00:18:42.390 --> 00:18:45.690 is highly debated. Did Pavlov always use a bell? 00:18:45.829 --> 00:18:49.029 The popular belief is just so firmly entrenched. 00:18:49.559 --> 00:18:51.799 Pavlov's bell. It's concise. It's memorable. 00:18:52.039 --> 00:18:54.700 But the scholarly consensus is that the bell 00:18:54.700 --> 00:18:57.680 is basically a cultural shorthand. A myth. A 00:18:57.680 --> 00:19:00.279 powerful myth. His research records detail the 00:19:00.279 --> 00:19:02.900 use of an extensive variety of stimuli to create 00:19:02.900 --> 00:19:05.019 that association. Okay, so what are some of the 00:19:05.019 --> 00:19:07.559 other conditional stimuli his team used? Oh, 00:19:07.599 --> 00:19:09.920 we have detailed records of his team using electric 00:19:09.920 --> 00:19:13.460 shocks, whistles, metronomes. The rhythmic ticking 00:19:13.460 --> 00:19:15.900 was a favorite of his tuning forks to produce 00:19:15.900 --> 00:19:19.079 very precise tones. And various visual stimuli 00:19:19.079 --> 00:19:21.480 like flashing lights or the rotation of objects. 00:19:21.599 --> 00:19:23.519 The goal was to test the limits of the nervous 00:19:23.519 --> 00:19:26.440 system's capacity to form associations. Exactly, 00:19:26.640 --> 00:19:29.140 under varying levels of... intensity so the man 00:19:29.140 --> 00:19:32.400 who won a nobel for surgical genius probably 00:19:32.400 --> 00:19:34.799 didn't even use the bell he's famous for The 00:19:34.799 --> 00:19:37.839 irony is just profound. A. Charles Catania, among 00:19:37.839 --> 00:19:40.680 others, cast serious doubt in 1994 on whether 00:19:40.680 --> 00:19:43.160 Pavlov ever actually used a bell in his primary 00:19:43.160 --> 00:19:45.059 experiments. So where did the image come from? 00:19:45.299 --> 00:19:47.240 Scholars like Lippmann suggested the popular 00:19:47.240 --> 00:19:50.220 imagery was codified and popularized in the West 00:19:50.220 --> 00:19:53.240 by his contemporaries, specifically Vladimir 00:19:53.240 --> 00:19:56.460 Mikhailovich Bektarev and, crucially, John B. 00:19:56.500 --> 00:19:59.220 Watson, who adopted Pavlovian ideas wholesale. 00:19:59.640 --> 00:20:02.019 It just highlights how a complex scientific finding 00:20:02.019 --> 00:20:05.009 can get compressed and, you know. sometimes distorted 00:20:05.009 --> 00:20:08.170 by cultural retelling to the point that the symbol 00:20:08.170 --> 00:20:11.450 completely replaces the substance. So if we connect 00:20:11.450 --> 00:20:14.130 this to the bigger picture, Pavlov never really 00:20:14.130 --> 00:20:16.809 saw himself as having abandoned physiology for 00:20:16.809 --> 00:20:20.049 psychology. No. He viewed conditioning not as 00:20:20.049 --> 00:20:22.089 the end goal, but as an incredibly sensitive 00:20:22.089 --> 00:20:25.349 tool to map the ultimate physiological mechanism, 00:20:25.690 --> 00:20:28.450 the nervous system itself. He was always looking 00:20:28.450 --> 00:20:31.329 for objective, measurable biomarkers for temperament 00:20:31.329 --> 00:20:33.390 types, which were originally described. thousands 00:20:33.390 --> 00:20:35.890 of years ago by Hippocrates and Galen. Exactly. 00:20:36.109 --> 00:20:39.609 He wanted a rigorous biological basis for personality 00:20:39.609 --> 00:20:41.970 in a way. He wanted to move it out of the realm 00:20:41.970 --> 00:20:45.089 of philosophy or humorism and into hard science. 00:20:45.250 --> 00:20:47.190 And he called these essential distinctions the 00:20:47.190 --> 00:20:49.769 properties of nervous systems. Precisely. His 00:20:49.769 --> 00:20:51.829 work in the conditioning lab showed him that 00:20:51.829 --> 00:20:54.069 while all dogs could be conditioned, they all 00:20:54.069 --> 00:20:56.670 responded wildly differently. Some learned fast 00:20:56.670 --> 00:20:59.250 and resisted forgetting. Others were highly reactive 00:20:59.250 --> 00:21:02.500 and some were slow and steady. And he identified 00:21:02.500 --> 00:21:05.539 three core properties he believed governed an 00:21:05.539 --> 00:21:08.099 organism's reaction to stimuli and its overall 00:21:08.099 --> 00:21:10.819 temperament. Right. The first was strength of 00:21:10.819 --> 00:21:13.380 the nervous process. This relates to the maximum 00:21:13.380 --> 00:21:15.599 intensity of stimulation the system can handle 00:21:15.599 --> 00:21:18.099 before it just breaks down. Okay. The second 00:21:18.099 --> 00:21:20.920 was mobility of nervous processes, how quickly 00:21:20.920 --> 00:21:23.720 the system can transition between states of excitation 00:21:23.720 --> 00:21:26.980 and inhibition, basically how adaptable it is. 00:21:27.099 --> 00:21:29.539 And the third? A balance between excitation and 00:21:29.539 --> 00:21:32.589 inhibition. Excitation is the drive to react. 00:21:33.069 --> 00:21:35.890 Inhibition is the capacity to stop or suppress 00:21:35.890 --> 00:21:38.970 a reaction. So he essentially updated the classical 00:21:38.970 --> 00:21:41.809 four temperaments using these rigorous scientific 00:21:41.809 --> 00:21:44.529 biomarkers. That's a huge intellectual achievement. 00:21:44.809 --> 00:21:46.990 It is. He's finding a physiological foundation 00:21:46.990 --> 00:21:49.849 for ancient philosophical concepts. So how did 00:21:49.849 --> 00:21:52.390 he map them? He derived four temperament types 00:21:52.390 --> 00:21:54.430 based on how those three properties interacted. 00:21:54.789 --> 00:21:57.589 He correlated them to the classical names but 00:21:57.589 --> 00:21:59.730 gave them a scientific definition. Okay, so number 00:21:59.730 --> 00:22:02.190 one. The strong and impetuous type, which he 00:22:02.190 --> 00:22:04.730 correlated to the choleric. They have strong 00:22:04.730 --> 00:22:07.430 nervous processes, but often a poor balance, 00:22:07.670 --> 00:22:10.789 leading to rapid, sometimes explosive reactions. 00:22:11.210 --> 00:22:13.880 Number two. The strong, equilibrated, and quiet 00:22:13.880 --> 00:22:16.799 type, which is the phlegmatic. They possess strong, 00:22:16.880 --> 00:22:19.160 stable processes that are well -balanced but 00:22:19.160 --> 00:22:21.920 low in mobility. So they're steady and calm but 00:22:21.920 --> 00:22:24.460 slow to change habits. Right. And three. The 00:22:24.460 --> 00:22:26.859 strong, equilibrated, and lively type, or the 00:22:26.859 --> 00:22:29.680 sanguine. Strong, balanced, and highly mobile 00:22:29.680 --> 00:22:32.859 processes, making them energetic, adaptable, 00:22:32.859 --> 00:22:35.059 and quick to respond. And finally, number four. 00:22:35.559 --> 00:22:38.390 The weak type. correlated with the melancholic. 00:22:38.509 --> 00:22:40.809 This is characterized by a nervous system with 00:22:40.809 --> 00:22:43.349 low strength. Their system just struggles to 00:22:43.349 --> 00:22:45.630 cope with strong stimulation and quickly shifts 00:22:45.630 --> 00:22:48.609 to protective inhibition. That concept of the 00:22:48.609 --> 00:22:50.910 weak type brings us directly to another fascinating 00:22:50.910 --> 00:22:53.809 area of his research, transmarginal inhibition, 00:22:53.809 --> 00:22:55.849 or TMI. You mentioned that it's a biological 00:22:55.849 --> 00:22:58.150 defense mechanism against overwhelming stress. 00:22:58.720 --> 00:23:01.339 It is. And it's a concept that has immense modern 00:23:01.339 --> 00:23:04.240 relevance. Pavlov and his researchers studied 00:23:04.240 --> 00:23:07.519 TMI, the body's natural response of just shutting 00:23:07.519 --> 00:23:10.839 down when it's exposed to stress, pain or stimulation 00:23:10.839 --> 00:23:13.400 that exceeds its capacity. So in the lab, this 00:23:13.400 --> 00:23:15.039 might have been observed when a dog conditioned 00:23:15.039 --> 00:23:17.940 to, say, a really loud sound suddenly stopped 00:23:17.940 --> 00:23:21.079 responding. Or even fell asleep. It's like a 00:23:21.079 --> 00:23:23.619 circuit breaker in the nervous system. The stress 00:23:23.619 --> 00:23:26.220 or stimulation gets too high, and rather than 00:23:26.220 --> 00:23:28.720 overloading, the system just flips a switch to 00:23:28.720 --> 00:23:31.400 protect itself. That's a perfect analogy. The 00:23:31.400 --> 00:23:34.180 system reaches a critical threshold, and instead 00:23:34.180 --> 00:23:36.539 of reacting more intensely, which is excitation, 00:23:36.839 --> 00:23:39.859 it effectively forces self -inhibition to protect 00:23:39.859 --> 00:23:42.559 the delicate cortical cells from damage. And 00:23:42.559 --> 00:23:45.359 Pavlov noted that the most basic inherited difference 00:23:45.359 --> 00:23:47.900 across temperaments was how soon they reached 00:23:47.900 --> 00:23:51.809 this shutdown point. Exactly. The weak type or 00:23:51.809 --> 00:23:54.170 melancholic temperament, for instance, reaches 00:23:54.170 --> 00:23:57.210 that critical threshold much, much faster. It's 00:23:57.210 --> 00:23:59.470 a profound realization that stress tolerance 00:23:59.470 --> 00:24:02.769 is, at least in part, physiologically determined. 00:24:02.930 --> 00:24:04.549 It is. But let's look at his official legacy. 00:24:04.829 --> 00:24:07.210 His principles were crucial for the developing 00:24:07.210 --> 00:24:10.150 field of comparative psychology. and provided 00:24:10.150 --> 00:24:13.049 the groundwork for behaviorism, popularized by 00:24:13.049 --> 00:24:16.809 John B. Watson and B .F. Skinner. Oh, he is undeniably 00:24:16.809 --> 00:24:20.549 foundational. A 2002 survey ranked Pavlov as 00:24:20.549 --> 00:24:23.309 the 24th most cited psychologist of the 20th 00:24:23.309 --> 00:24:25.910 century, which is remarkable considering his 00:24:25.910 --> 00:24:28.970 primary field was medicine. His insistence on 00:24:28.970 --> 00:24:31.210 objective measurement and controlling the environment 00:24:31.210 --> 00:24:34.029 became the methodological bedrock for the entire 00:24:34.029 --> 00:24:36.230 behaviorist movement. Even though he disagreed 00:24:36.230 --> 00:24:38.410 with their rejection of internal states. And 00:24:38.410 --> 00:24:41.250 his work didn't stay locked in theory. His principles 00:24:41.250 --> 00:24:44.849 are central to modern behavior therapy. For you, 00:24:44.849 --> 00:24:46.529 the listener, who might be interested in application, 00:24:47.069 --> 00:24:50.069 where do we see his ideas at work today beyond 00:24:50.069 --> 00:24:53.559 just treating phobias? Well, systematic desensitization 00:24:53.559 --> 00:24:56.299 for phobias is the classic example. If you have 00:24:56.299 --> 00:24:58.359 a fear of flying, a therapist uses conditioning 00:24:58.359 --> 00:25:01.359 to gradually pair the feared stimulus, thought 00:25:01.359 --> 00:25:04.119 of a plane, with a relaxed state. They're essentially 00:25:04.119 --> 00:25:06.220 retraining the fear response. But let's bring 00:25:06.220 --> 00:25:08.460 this application right into daily life, maybe 00:25:08.460 --> 00:25:10.740 in education. You're talking about antecedent 00:25:10.740 --> 00:25:13.099 control strategies in the classroom. And it's 00:25:13.099 --> 00:25:15.680 a direct lineage from Pavlov's method, which 00:25:15.680 --> 00:25:18.160 showed that the cue, the antecedent, dictates 00:25:18.160 --> 00:25:20.420 the response. So what does that look like in 00:25:20.420 --> 00:25:23.700 practice? Antecedent control involves manipulating 00:25:23.700 --> 00:25:26.460 the conditions before the behavior to make the 00:25:26.460 --> 00:25:29.359 desired behavior more likely or the undesired 00:25:29.359 --> 00:25:32.220 behavior less likely. Let's have a concrete example. 00:25:32.559 --> 00:25:35.240 Say a teacher constantly struggles to get their 00:25:35.240 --> 00:25:37.720 class to quiet down and start working after lunch. 00:25:37.940 --> 00:25:40.200 Instead of constantly yelling or reacting after 00:25:40.200 --> 00:25:42.680 the disruptive behavior starts, which is a consequence 00:25:42.680 --> 00:25:45.839 strategy, antecedent control uses a conditional 00:25:45.839 --> 00:25:49.700 stimulus preventatively. For instance, the teacher 00:25:49.700 --> 00:25:52.839 might consistently play a specific, calming piece 00:25:52.839 --> 00:25:55.099 of classical music, the conditional stimulus, 00:25:55.359 --> 00:25:57.880 every single day, only for the two minutes immediately 00:25:57.880 --> 00:26:01.359 before quiet work time. Over time, that specific 00:26:01.359 --> 00:26:04.000 music becomes conditioned to the state of quiet 00:26:04.000 --> 00:26:07.859 focus. The music, the antecedent, now cues the 00:26:07.859 --> 00:26:10.759 appropriate behavior. The research is compelling. 00:26:11.339 --> 00:26:13.880 Antecedent based interventions rooted directly 00:26:13.880 --> 00:26:16.720 in classical conditioning are empirically supported 00:26:16.720 --> 00:26:19.420 for producing immediate reductions in problem 00:26:19.420 --> 00:26:22.660 behaviors in a classroom environment. Pavlov 00:26:22.660 --> 00:26:24.579 showed us that the environment is often the cue 00:26:24.579 --> 00:26:26.940 for the response, not just the consequence. Yeah. 00:26:27.539 --> 00:26:31.000 So stepping back into his biography, we encounter 00:26:31.000 --> 00:26:35.069 the most politically turbulent and. frankly paradoxical 00:26:35.069 --> 00:26:37.829 part of his life. It really is. Pavlov lived 00:26:37.829 --> 00:26:40.390 and conducted his key research during a period 00:26:40.390 --> 00:26:43.390 of massive political upheaval in Russia. He's 00:26:43.390 --> 00:26:45.950 straddling the end of the czarist era, the revolution, 00:26:46.190 --> 00:26:48.569 and the dawn of the Soviet regime. It creates 00:26:48.569 --> 00:26:50.390 a cognitive dissonance that's really hard to 00:26:50.390 --> 00:26:53.180 reconcile. Despite his work being rooted in Tsarist 00:26:53.180 --> 00:26:55.299 Russia, he continued his work for decades under 00:26:55.299 --> 00:26:57.460 the Soviet regime, directing the Department of 00:26:57.460 --> 00:26:59.759 Physiology at the Institute of Experimental Medicine 00:26:59.759 --> 00:27:02.720 for a staggering 45 years. And the paradox is 00:27:02.720 --> 00:27:04.819 that he was simultaneously a political thorn 00:27:04.819 --> 00:27:07.119 in the side of the regime and their international 00:27:07.119 --> 00:27:09.599 scientific showpiece. He was highly regarded 00:27:09.599 --> 00:27:12.019 by the Soviet government, praised by Vladimir 00:27:12.019 --> 00:27:15.299 Lenin herself, and he received significant money, 00:27:15.440 --> 00:27:17.740 support, and honors for his laboratory. Which 00:27:17.740 --> 00:27:20.019 almost guaranteed his survival and continued 00:27:20.019 --> 00:27:22.680 ability to do research. The initial Soviet interest 00:27:22.680 --> 00:27:26.319 was both pragmatic and ideological. Lenin and 00:27:26.319 --> 00:27:28.579 the Bolsheviks saw Pavlov's work on conditioned 00:27:28.579 --> 00:27:31.200 reflexes as the scientific validation for creating 00:27:31.200 --> 00:27:34.619 Homo Sovieticus, the new Soviet man. A being 00:27:34.619 --> 00:27:36.799 whose behavior could be engineered through environmental 00:27:36.799 --> 00:27:39.359 conditioning? Exactly. They poured tremendous 00:27:39.359 --> 00:27:42.200 resources into his work to prove the scientific 00:27:42.200 --> 00:27:45.740 superiority of the Marxist -Leninist state. So 00:27:45.740 --> 00:27:48.380 the state essentially funded his scientific fortress. 00:27:49.019 --> 00:27:51.380 But this financial support did not buy his political 00:27:51.380 --> 00:27:54.000 silence or his approval? No, it did not. Which 00:27:54.000 --> 00:27:56.299 is astonishing considering the increasing repression 00:27:56.299 --> 00:27:59.240 under Stalin. It's incredible. Pavlov openly 00:27:59.240 --> 00:28:02.279 and consistently concealed his disapproval and 00:28:02.279 --> 00:28:05.119 outright contempt for Soviet communism. He was 00:28:05.119 --> 00:28:08.160 remarkably vocal about his opposition, a stance 00:28:08.160 --> 00:28:10.930 that was incredibly dangerous at the time. Especially 00:28:10.930 --> 00:28:13.950 in the 1920s and 30s, when intellectuals and 00:28:13.950 --> 00:28:16.490 scientists who expressed dissent were routinely 00:28:16.490 --> 00:28:19.890 purged, imprisoned or executed. So what are the 00:28:19.890 --> 00:28:22.470 best examples of his open contempt and protest 00:28:22.470 --> 00:28:24.609 where he really risked everything? There are 00:28:24.609 --> 00:28:26.490 several powerful statements that you have to 00:28:26.490 --> 00:28:29.230 put into context. The Communist Party saw itself 00:28:29.230 --> 00:28:32.970 as conducting this grand, necessary social experiment. 00:28:33.230 --> 00:28:36.849 And in 1923, Pavlov publicly stated that he would 00:28:36.849 --> 00:28:40.049 not sacrifice even the hind leg of a frog. to 00:28:40.049 --> 00:28:42.569 the type of social experiment that the communist 00:28:42.569 --> 00:28:45.230 regime was conducting in Russia. That is a direct 00:28:45.230 --> 00:28:47.670 slap in the face. He's comparing his meticulously 00:28:47.670 --> 00:28:50.509 controlled ethical scientific work to the Bolshevik 00:28:50.509 --> 00:28:52.849 revolution and finding the revolution to be less 00:28:52.849 --> 00:28:55.769 valuable than a frog's limb. That level of dissent 00:28:55.769 --> 00:28:58.750 was suicidal for almost anyone else, and he escalated 00:28:58.750 --> 00:29:00.990 the criticism as the repression deepened. In 00:29:00.990 --> 00:29:04.410 1927, Amidst forced collectivization and the 00:29:04.410 --> 00:29:07.150 increasing crackdown on non -party members, he 00:29:07.150 --> 00:29:09.910 wrote a direct letter to Joseph Stalin. To Stalin 00:29:09.910 --> 00:29:12.789 himself, protesting the harsh treatment of Russian 00:29:12.789 --> 00:29:15.509 intellectuals and stating with remarkable candor 00:29:15.509 --> 00:29:17.890 that he was ashamed to be a Russian. How did 00:29:17.890 --> 00:29:20.289 that letter not result in his immediate disappearance? 00:29:20.769 --> 00:29:23.230 Again, it speaks to the global symbolic value 00:29:23.230 --> 00:29:26.779 of Pavlov. He was the only Russian Nobel laureate, 00:29:26.779 --> 00:29:28.799 and his work was deemed essential propaganda. 00:29:29.440 --> 00:29:32.359 The Soviets made a calculated, pragmatic decision 00:29:32.359 --> 00:29:34.839 that the benefit of having him as a symbol of 00:29:34.839 --> 00:29:38.140 Soviet science, even a critical one, outweighed 00:29:38.140 --> 00:29:40.559 the cost of silencing him. So they just showered 00:29:40.559 --> 00:29:42.400 him with funding and built him world -class facilities. 00:29:42.779 --> 00:29:45.200 Effectively granting him special immunity. And 00:29:45.200 --> 00:29:47.500 did he try to use his prestige to protect his 00:29:47.500 --> 00:29:50.400 colleagues? Yes. This is perhaps his most heroic 00:29:50.400 --> 00:29:53.779 political act. After the murder of Sergei Kirov 00:29:53.779 --> 00:29:57.039 in 1934, which was used as the pretext to unleash 00:29:57.039 --> 00:30:00.359 the massive purges of the late 1930s, Pavlov 00:30:00.359 --> 00:30:02.900 wrote several impassioned letters to Vyacheslav 00:30:02.900 --> 00:30:05.980 Molotov, one of Stalin's key lieutenants, criticizing 00:30:05.980 --> 00:30:08.619 those mass persecutions and asking specifically 00:30:08.619 --> 00:30:11.039 for the reconsideration of cases involving people 00:30:11.039 --> 00:30:13.220 he knew personally. So he wasn't just safe in 00:30:13.220 --> 00:30:15.500 his laboratory. He was actively leveraging his 00:30:15.500 --> 00:30:17.940 position to intervene in the state terror machine. 00:30:18.400 --> 00:30:21.559 He was. It was a perilous, brave, and extremely 00:30:21.559 --> 00:30:24.799 rare use of scientific prestige to try and inject 00:30:24.799 --> 00:30:28.380 some humanity into a brutal system. It seems, 00:30:28.380 --> 00:30:30.740 though, that his attitude softened slightly in 00:30:30.740 --> 00:30:33.680 his final years. Was this just resignation, or 00:30:33.680 --> 00:30:35.880 did he genuinely see some positive changes? It 00:30:35.880 --> 00:30:38.980 was a nuanced shift. It seemed born out of appreciation 00:30:38.980 --> 00:30:41.700 for the state's massive investment in his field 00:30:41.700 --> 00:30:45.440 rather than ideological alignment. So while never 00:30:45.440 --> 00:30:48.180 endorsing the politics, he did publicly praise 00:30:48.180 --> 00:30:50.420 the Soviet government for its vigorous financial 00:30:50.420 --> 00:30:53.180 and infrastructural support of scientific institutions. 00:30:53.500 --> 00:30:56.000 He specifically noted the stark contrast between 00:30:56.000 --> 00:30:58.980 the facilities he had then and the cramped, underfunded 00:30:58.980 --> 00:31:01.240 conditions he worked in during the Tsarist era. 00:31:01.440 --> 00:31:03.660 And he seems to have held a flicker of hope. 00:31:03.960 --> 00:31:05.859 right until the end. A few months before his 00:31:05.859 --> 00:31:07.980 death, he expressed pleasure at the draft of 00:31:07.980 --> 00:31:11.420 the 1936 Stalin Constitution. He saw the language 00:31:11.420 --> 00:31:13.539 of rights and freedoms, however illusory they 00:31:13.539 --> 00:31:16.220 were in practice, as the apparent dawn of a more 00:31:16.220 --> 00:31:19.059 free and democratic Soviet Union. A move toward 00:31:19.059 --> 00:31:21.799 political liberalization that tragically never 00:31:21.799 --> 00:31:24.819 materialized before he died in 1936. And outside 00:31:24.819 --> 00:31:27.299 of his politics and his lab, his personal life 00:31:27.299 --> 00:31:30.039 was marked by incredible hardship, too. That's 00:31:30.039 --> 00:31:31.799 right. The famous scientist started out very 00:31:31.799 --> 00:31:35.250 poor. He did. Pavlov, despite growing up in a 00:31:35.250 --> 00:31:38.250 priestly household, was an atheist. He said he 00:31:38.250 --> 00:31:40.549 became an unbeliever and atheist in my school 00:31:40.549 --> 00:31:42.970 years while he was still a seminarian. And his 00:31:42.970 --> 00:31:46.650 marriage in 1881 to Serafima Vasilyevna Karchevskaya, 00:31:46.650 --> 00:31:49.670 who he called Sarah, was marked by nine years 00:31:49.670 --> 00:31:52.440 of extreme poverty. They often had to live apart 00:31:52.440 --> 00:31:54.940 or stay with others, relying on Sarah's small 00:31:54.940 --> 00:31:57.759 teaching salary, while Pavlov struggled to secure 00:31:57.759 --> 00:32:00.640 a permanent research position. Sarah was really 00:32:00.640 --> 00:32:03.140 his indispensable emotional and financial backbone 00:32:03.140 --> 00:32:06.180 during those early difficult years. And they 00:32:06.180 --> 00:32:08.480 faced immense personal tragedy as well. Yes. 00:32:08.680 --> 00:32:11.519 Sarah's first pregnancy ended in a miscarriage. 00:32:11.539 --> 00:32:13.720 And while he eventually had four surviving children, 00:32:14.019 --> 00:32:16.240 they suffered the tragic loss of their first 00:32:16.240 --> 00:32:19.059 son, Merchick, in childhood, which caused Sarah 00:32:19.059 --> 00:32:21.460 deep and lasting depression. And their youngest 00:32:21.460 --> 00:32:24.380 surviving son, Visevolod, also died of pancreatic 00:32:24.380 --> 00:32:27.799 cancer in 1935, just a year before Pavlov himself. 00:32:28.400 --> 00:32:31.039 Hardship was just constant for him, even as his 00:32:31.039 --> 00:32:33.640 fame grew. And even his final moments were a 00:32:33.640 --> 00:32:36.299 testament to his ingrained instinct for research. 00:32:36.859 --> 00:32:39.740 A scientist until his very last breath. Absolutely. 00:32:40.099 --> 00:32:44.480 Pavlov died on February 27, 1936 at age 86 from 00:32:44.480 --> 00:32:47.339 double pneumonia. He remained conscious until 00:32:47.339 --> 00:32:49.940 his final moments, and in an astonishing demonstration 00:32:49.940 --> 00:32:53.079 of his commitment to empirical observation, he 00:32:53.079 --> 00:32:55.319 asked a student to sit beside his bed and record 00:32:55.319 --> 00:32:57.920 the subjective circumstances of his dying. He 00:32:57.920 --> 00:33:00.119 dictated his symptoms, the progression of his 00:33:00.119 --> 00:33:03.970 pain, his failing senses. all to create unique, 00:33:04.009 --> 00:33:07.009 real -time evidence of the terminal phase of 00:33:07.009 --> 00:33:10.009 life. So we started this deep dive with the simplistic 00:33:10.009 --> 00:33:12.529 idea of a bell and a salivating dog, and what 00:33:12.529 --> 00:33:14.970 we've discovered is a monumentally complex man. 00:33:15.230 --> 00:33:18.289 A surgical pioneer who won the Nobel for meticulously 00:33:18.289 --> 00:33:20.789 mapping physiological digestion. A fierce, open 00:33:20.789 --> 00:33:22.869 critic of the Soviet government who was simultaneously 00:33:22.869 --> 00:33:25.529 funded and protected by it. And a researcher 00:33:25.529 --> 00:33:27.430 whose accidental observation just fundamentally 00:33:27.430 --> 00:33:30.049 changed how we view learning and behavior. His 00:33:30.049 --> 00:33:32.470 conditional reflex influenced not just the scientific 00:33:32.470 --> 00:33:35.529 community founding behaviorism, comparative psychology, 00:33:35.970 --> 00:33:38.569 and modern therapeutic techniques like systematic 00:33:38.569 --> 00:33:41.789 desensitization, but it also infiltrated popular 00:33:41.789 --> 00:33:45.190 culture. Right. We see the direct influence of 00:33:45.190 --> 00:33:48.150 Pavlovian conditioning in works like Aldous Huxley's 00:33:48.150 --> 00:33:50.269 Brave New World, where babies are conditioned 00:33:50.269 --> 00:33:53.990 to dislike books and nature. And in Thomas Pynchon's 00:33:53.990 --> 00:33:56.910 complex, conditioning -laden narrative in Gravity's 00:33:56.910 --> 00:34:00.640 Rainbow. His legacy is concrete, too. The Pavlov 00:34:00.640 --> 00:34:03.339 Institute of Physiology, which he founded in 00:34:03.339 --> 00:34:06.319 1925, was named after him following his death. 00:34:06.559 --> 00:34:08.599 The philosopher Bertrand Russell once observed 00:34:08.599 --> 00:34:10.920 that while it's open to question whether Pavlov's 00:34:10.920 --> 00:34:13.199 methods cover the whole of human behavior, they 00:34:13.199 --> 00:34:15.340 cover a very large field. And they showed how 00:34:15.340 --> 00:34:17.760 to apply scientific methods with quantitative 00:34:17.760 --> 00:34:21.280 exactitude. It's that exactitude, that dedication 00:34:21.280 --> 00:34:24.099 to measurable, observable physiological truth 00:34:24.099 --> 00:34:26.599 that really defined his life. From the operating 00:34:26.599 --> 00:34:28.780 table maintaining the vagus nerve to the lecture 00:34:28.780 --> 00:34:31.239 hall explaining the basis of temperament. Which 00:34:31.239 --> 00:34:33.400 brings us back finally to one of his lesser known 00:34:33.400 --> 00:34:36.239 but most fascinating concepts, transmarginal 00:34:36.239 --> 00:34:39.519 inhibition, PMI. The body's natural circuit breaker, 00:34:39.699 --> 00:34:42.019 the shutdown response to overwhelming stress. 00:34:42.440 --> 00:34:45.099 So if Pavlov's research showed us that our innate 00:34:45.099 --> 00:34:47.599 temperaments dictate how quickly we reach that 00:34:47.599 --> 00:34:50.320 critical shutdown point under duress, consider 00:34:50.320 --> 00:34:53.090 this final thought. How might modern digital 00:34:53.090 --> 00:34:56.269 information overload the constant high -intensity 00:34:56.269 --> 00:35:00.110 247 stream of data, stimulation, and manufactured 00:35:00.110 --> 00:35:03.289 urgency, creating universal chronic conditions 00:35:03.289 --> 00:35:05.590 that push all of us, regardless of our underlying 00:35:05.590 --> 00:35:08.110 temperament, closer and closer to that critical 00:35:08.110 --> 00:35:10.670 threshold of nervous system collapse? The very 00:35:10.670 --> 00:35:12.690 environment we inhabit today might be forcing 00:35:12.690 --> 00:35:15.429 a systemic TMI response in an effort to cope, 00:35:15.530 --> 00:35:18.090 making Pavlov's forgotten concept more relevant 00:35:18.090 --> 00:35:19.090 now than ever before.