WEBVTT 00:00:00.000 --> 00:00:02.520 align:middle line:84% The following content is provided under a Creative 00:00:02.520 --> 00:00:04.030 align:middle line:90% Commons license. 00:00:04.030 --> 00:00:06.370 align:middle line:84% Your support will help MIT OpenCourseWare 00:00:06.370 --> 00:00:10.740 align:middle line:84% continue to offer high quality educational resources for free. 00:00:10.740 --> 00:00:13.350 align:middle line:84% To make a donation, or view additional materials 00:00:13.350 --> 00:00:17.237 align:middle line:84% from hundreds of MIT courses, visit MIT OpenCourseWare 00:00:17.237 --> 00:00:17.862 align:middle line:90% at ocw.mit.edu. 00:00:17.862 --> 00:00:21.312 align:middle line:90% 00:00:21.312 --> 00:00:23.020 align:middle line:84% PROFESSOR: Did anybody have any questions 00:00:23.020 --> 00:00:26.250 align:middle line:84% about this path analysis, which is where 00:00:26.250 --> 00:00:29.070 align:middle line:90% we ended the class last time? 00:00:29.070 --> 00:00:37.780 align:middle line:84% It's a way to find the probability for two individuals 00:00:37.780 --> 00:00:42.100 align:middle line:84% when you know they're related in some way. 00:00:42.100 --> 00:00:43.150 align:middle line:90% But if you have their-- 00:00:43.150 --> 00:00:45.700 align:middle line:90% 00:00:45.700 --> 00:00:50.920 align:middle line:84% you can draw the family tree, you're 00:00:50.920 --> 00:00:54.510 align:middle line:84% able to then, using path analysis, 00:00:54.510 --> 00:01:00.740 align:middle line:84% you can find the probability that the two alleles at one 00:01:00.740 --> 00:01:04.047 align:middle line:84% locus are identical, or how many of them 00:01:04.047 --> 00:01:05.130 align:middle line:90% are going to be identical. 00:01:05.130 --> 00:01:10.480 align:middle line:90% 00:01:10.480 --> 00:01:13.420 align:middle line:84% It's called the inbreeding coefficient, 00:01:13.420 --> 00:01:14.815 align:middle line:90% or the coefficient of kinship. 00:01:14.815 --> 00:01:18.200 align:middle line:90% 00:01:18.200 --> 00:01:21.820 align:middle line:90% Both terms are used. 00:01:21.820 --> 00:01:24.010 align:middle line:84% But you can use the same thing to compute 00:01:24.010 --> 00:01:28.806 align:middle line:84% just how many genes do you get from your great grandparent, 00:01:28.806 --> 00:01:29.306 align:middle line:90% for example. 00:01:29.306 --> 00:01:39.220 align:middle line:90% 00:01:39.220 --> 00:01:43.690 align:middle line:84% So this is the only slide from the first class 00:01:43.690 --> 00:01:45.220 align:middle line:90% I didn't get to. 00:01:45.220 --> 00:01:51.220 align:middle line:84% We were talking about notes from EO Wilson's book. 00:01:51.220 --> 00:01:57.340 align:middle line:84% I read the abridged addition for making those notes. 00:01:57.340 --> 00:02:01.500 align:middle line:84% But he talks about the possibility 00:02:01.500 --> 00:02:03.170 align:middle line:90% of inbreeding taboos. 00:02:03.170 --> 00:02:07.240 align:middle line:84% But when he introduces it he uses some more terms 00:02:07.240 --> 00:02:09.729 align:middle line:90% that are interesting. 00:02:09.729 --> 00:02:14.970 align:middle line:84% He introduces by defining the effective population number. 00:02:14.970 --> 00:02:19.410 align:middle line:84% And that, I've defined it at the bottom there, 00:02:19.410 --> 00:02:22.190 align:middle line:84% the number of individuals in an ideal randomly 00:02:22.190 --> 00:02:24.940 align:middle line:84% breeding population, with one to one 00:02:24.940 --> 00:02:29.970 align:middle line:84% sex ratio, that would have the same rate of heterozygocity 00:02:29.970 --> 00:02:34.580 align:middle line:84% decrease as the total population under consideration. 00:02:34.580 --> 00:02:38.626 align:middle line:84% So that's what makes it the effective population. 00:02:38.626 --> 00:02:41.650 align:middle line:90% 00:02:41.650 --> 00:02:45.890 align:middle line:84% It's usually the smallest number you can have and not 00:02:45.890 --> 00:02:47.225 align:middle line:90% have much inbreeding. 00:02:47.225 --> 00:02:50.320 align:middle line:90% 00:02:50.320 --> 00:02:52.270 align:middle line:84% At least you would not have anymore inbreeding 00:02:52.270 --> 00:02:54.320 align:middle line:84% than you would if they were bred randomly 00:02:54.320 --> 00:02:55.700 align:middle line:90% in the larger population. 00:02:55.700 --> 00:02:59.350 align:middle line:90% 00:02:59.350 --> 00:03:01.850 align:middle line:84% And the numbers aren't really big. 00:03:01.850 --> 00:03:05.240 align:middle line:84% They get as low as 10 in some species. 00:03:05.240 --> 00:03:11.050 align:middle line:84% But they often are closer to 100. 00:03:11.050 --> 00:03:14.420 align:middle line:84% And then he talks about Wright's Island Model. 00:03:14.420 --> 00:03:21.450 align:middle line:84% Now what that is he has a model of a population that's 00:03:21.450 --> 00:03:25.870 align:middle line:90% divided up into smaller groups. 00:03:25.870 --> 00:03:32.150 align:middle line:84% And we know that it's probably, at least very roughly, 00:03:32.150 --> 00:03:35.350 align:middle line:84% many populations are divided that way-- certainly humans 00:03:35.350 --> 00:03:37.425 align:middle line:84% were throughout much of our evolution. 00:03:37.425 --> 00:03:40.280 align:middle line:90% 00:03:40.280 --> 00:03:42.930 align:middle line:84% That's why he calls it the island model, 00:03:42.930 --> 00:03:45.510 align:middle line:84% because he's got the population divided 00:03:45.510 --> 00:03:50.290 align:middle line:84% into these different groups that are-- 00:03:50.290 --> 00:03:52.950 align:middle line:84% he computed how big would those groups 00:03:52.950 --> 00:03:57.730 align:middle line:84% have to be in order to meet this effective population number 00:03:57.730 --> 00:03:59.620 align:middle line:90% definition. 00:03:59.620 --> 00:04:03.410 align:middle line:84% And then what are the advantages of a population being 00:04:03.410 --> 00:04:05.970 align:middle line:90% divided that way? 00:04:05.970 --> 00:04:08.060 align:middle line:84% And there very clear advantages because when 00:04:08.060 --> 00:04:14.820 align:middle line:84% you have smaller groups the genetic differences that 00:04:14.820 --> 00:04:18.570 align:middle line:84% appear in the different groups will differ. 00:04:18.570 --> 00:04:22.900 align:middle line:84% And so you will have small genetic differences appearing 00:04:22.900 --> 00:04:25.560 align:middle line:90% in these different groups. 00:04:25.560 --> 00:04:28.150 align:middle line:84% And they'll be maintained if they're not interbreeding. 00:04:28.150 --> 00:04:30.400 align:middle line:84% Of course they would share the genes as soon as they-- 00:04:30.400 --> 00:04:34.500 align:middle line:90% 00:04:34.500 --> 00:04:38.120 align:middle line:84% mating involved movement from one group to the other. 00:04:38.120 --> 00:04:41.030 align:middle line:84% But if they're truly isolated that wouldn't be happening. 00:04:41.030 --> 00:04:45.020 align:middle line:84% What would be the advantage to that? 00:04:45.020 --> 00:04:47.630 align:middle line:84% What would be the advantage if a population were 00:04:47.630 --> 00:04:49.490 align:middle line:90% divided that way? 00:04:49.490 --> 00:04:54.370 align:middle line:84% Well think if there were some big change in the environment, 00:04:54.370 --> 00:04:59.310 align:middle line:84% or new predators appeared, affecting all the groups. 00:04:59.310 --> 00:05:02.110 align:middle line:84% Well if there's genetic differences in the groups then 00:05:02.110 --> 00:05:04.320 align:middle line:84% you're going to get better survival in some groups 00:05:04.320 --> 00:05:07.060 align:middle line:90% than in others. 00:05:07.060 --> 00:05:15.330 align:middle line:84% And that's what Wright, what his model was able to show. 00:05:15.330 --> 00:05:18.455 align:middle line:84% And that's one of the consequences of that model. 00:05:18.455 --> 00:05:23.220 align:middle line:90% 00:05:23.220 --> 00:05:25.880 align:middle line:84% [? Menia ?] points out these, what 00:05:25.880 --> 00:05:28.050 align:middle line:84% he calls opposed selection tendencies that 00:05:28.050 --> 00:05:32.370 align:middle line:84% affects sociality, two very different effects 00:05:32.370 --> 00:05:36.750 align:middle line:84% in small groups-- that you have a greater chance of inbreeding, 00:05:36.750 --> 00:05:42.780 align:middle line:84% and inbreeding generally lowers individual fitness, 00:05:42.780 --> 00:05:46.940 align:middle line:84% depresses performance, lowers genetic adaptability. 00:05:46.940 --> 00:05:51.340 align:middle line:84% So that is more likely to happen especially 00:05:51.340 --> 00:05:54.070 align:middle line:84% if you're well below that effective population number. 00:05:54.070 --> 00:05:57.450 align:middle line:90% 00:05:57.450 --> 00:06:00.030 align:middle line:84% But in the small groups of related individuals 00:06:00.030 --> 00:06:02.310 align:middle line:84% there would be very clear advantages 00:06:02.310 --> 00:06:04.930 align:middle line:84% because of greater amounts of altruistic behavior 00:06:04.930 --> 00:06:07.690 align:middle line:90% in close cooperation and groups. 00:06:07.690 --> 00:06:11.370 align:middle line:90% 00:06:11.370 --> 00:06:14.580 align:middle line:84% And then he talks about a somewhat different concept, 00:06:14.580 --> 00:06:18.600 align:middle line:84% assortative mating, also known as homogamy. 00:06:18.600 --> 00:06:23.200 align:middle line:84% And this is the tendency you find in all animal groups, 00:06:23.200 --> 00:06:24.300 align:middle line:90% and certainly in humans. 00:06:24.300 --> 00:06:27.278 align:middle line:84% A tendency to choose a mate that looks similar to oneself 00:06:27.278 --> 00:06:28.320 align:middle line:90% or one's close relatives. 00:06:28.320 --> 00:06:34.250 align:middle line:90% 00:06:34.250 --> 00:06:35.590 align:middle line:90% What does that mean? 00:06:35.590 --> 00:06:37.425 align:middle line:84% Well it probably means that the group-- 00:06:37.425 --> 00:06:41.920 align:middle line:90% 00:06:41.920 --> 00:06:44.880 align:middle line:84% I was talking to the TA's about my worries 00:06:44.880 --> 00:06:48.010 align:middle line:84% that the second project will go out, too. 00:06:48.010 --> 00:06:52.990 align:middle line:84% It's a small chance it's in the connection, but I don't-- 00:06:52.990 --> 00:06:56.260 align:middle line:90% so far, so good. 00:06:56.260 --> 00:07:04.580 align:middle line:90% 00:07:04.580 --> 00:07:06.615 align:middle line:84% If you're going to always choose a mate, 00:07:06.615 --> 00:07:08.240 align:middle line:84% someone that looks similar to yourself, 00:07:08.240 --> 00:07:11.200 align:middle line:84% then the chances of the two shared genes, of course, 00:07:11.200 --> 00:07:12.540 align:middle line:90% might be greater. 00:07:12.540 --> 00:07:15.570 align:middle line:84% But that's only in a relatively small number 00:07:15.570 --> 00:07:17.715 align:middle line:84% of genes that affect the superficial appearance. 00:07:17.715 --> 00:07:23.680 align:middle line:90% 00:07:23.680 --> 00:07:26.360 align:middle line:90% That was the end of that class. 00:07:26.360 --> 00:07:33.160 align:middle line:90% 00:07:33.160 --> 00:07:34.700 align:middle line:84% Then I asked you to read the chapter 00:07:34.700 --> 00:07:38.905 align:middle line:84% on genes, genetic influences on social behavior. 00:07:38.905 --> 00:07:42.020 align:middle line:90% 00:07:42.020 --> 00:07:46.530 align:middle line:84% We want to know the difference between genetic determinants 00:07:46.530 --> 00:07:50.672 align:middle line:84% of behavioral traits, genetic determination, and what 00:07:50.672 --> 00:07:51.380 align:middle line:90% sociobiologists-- 00:07:51.380 --> 00:07:54.110 align:middle line:90% 00:07:54.110 --> 00:07:57.900 align:middle line:84% what their view concerning genes and behavior is. 00:07:57.900 --> 00:08:00.600 align:middle line:84% Because you know that they've been accused 00:08:00.600 --> 00:08:07.430 align:middle line:84% a lot of basically saying genes are us, 00:08:07.430 --> 00:08:10.720 align:middle line:90% major trends are genetic. 00:08:10.720 --> 00:08:12.970 align:middle line:84% Do the genes determine the development 00:08:12.970 --> 00:08:15.600 align:middle line:90% of specific social behaviors? 00:08:15.600 --> 00:08:17.400 align:middle line:84% First of all, I want you to think back 00:08:17.400 --> 00:08:19.920 align:middle line:90% to our discussion of ethology. 00:08:19.920 --> 00:08:24.800 align:middle line:84% We talked about Connor Lawrence and fixed action patterns. 00:08:24.800 --> 00:08:29.480 align:middle line:84% Because ethology was founded on the basis of the heriditability 00:08:29.480 --> 00:08:32.409 align:middle line:84% of fixed action patterns, and many of them 00:08:32.409 --> 00:08:34.099 align:middle line:90% are, of course, social behavior. 00:08:34.099 --> 00:08:39.059 align:middle line:90% 00:08:39.059 --> 00:08:44.070 align:middle line:84% But we also knew that a fixed action pattern's not totally 00:08:44.070 --> 00:08:47.130 align:middle line:90% determined by the genes. 00:08:47.130 --> 00:08:50.920 align:middle line:84% It depends on motivational levels. 00:08:50.920 --> 00:08:52.550 align:middle line:84% And the motivational intensity is 00:08:52.550 --> 00:08:56.510 align:middle line:84% influenced by many environmental variables. 00:08:56.510 --> 00:08:58.590 align:middle line:84% But the underlying action patterns, especially 00:08:58.590 --> 00:09:00.930 align:middle line:84% on the motor side, the fixed motor pattern, 00:09:00.930 --> 00:09:02.840 align:middle line:90% is considered genetic. 00:09:02.840 --> 00:09:06.190 align:middle line:84% And there's plenty of evidence for that. 00:09:06.190 --> 00:09:09.330 align:middle line:84% You can even get mouse populations 00:09:09.330 --> 00:09:10.810 align:middle line:84% that are genetically different that 00:09:10.810 --> 00:09:17.340 align:middle line:84% show differences in details of grooming behavior. 00:09:17.340 --> 00:09:22.870 align:middle line:84% And all the members that have one gene, one genetic variant, 00:09:22.870 --> 00:09:24.250 align:middle line:90% will show one type. 00:09:24.250 --> 00:09:27.430 align:middle line:84% And all of the individuals are almost identical. 00:09:27.430 --> 00:09:30.110 align:middle line:84% And the other groups are a little bit different. 00:09:30.110 --> 00:09:33.030 align:middle line:84% Certainly pretty strong evidence for genetic influences 00:09:33.030 --> 00:09:34.720 align:middle line:90% on that behavior. 00:09:34.720 --> 00:09:40.460 align:middle line:84% That is only social behavior, of course, if there's grooming 00:09:40.460 --> 00:09:42.340 align:middle line:90% of each other in a group. 00:09:42.340 --> 00:09:45.020 align:middle line:90% 00:09:45.020 --> 00:09:47.130 align:middle line:84% But I want you, next, to remember 00:09:47.130 --> 00:09:55.800 align:middle line:84% that the nature/nurture problem, the way that controversy 00:09:55.800 --> 00:09:59.900 align:middle line:84% is normally dealt with now, especially in sociobiology, 00:09:59.900 --> 00:10:02.350 align:middle line:90% is to remember that-- 00:10:02.350 --> 00:10:03.185 align:middle line:90% where are we here?-- 00:10:03.185 --> 00:10:08.530 align:middle line:90% 00:10:08.530 --> 00:10:12.220 align:middle line:84% that both nature and nurture are always involved. 00:10:12.220 --> 00:10:15.236 align:middle line:84% You never have a purely genetic determination. 00:10:15.236 --> 00:10:20.890 align:middle line:90% 00:10:20.890 --> 00:10:23.640 align:middle line:84% And the other thing that Alcott points out here 00:10:23.640 --> 00:10:26.690 align:middle line:84% is that the genetic studies most relevant to 00:10:26.690 --> 00:10:31.520 align:middle line:84% sociobiology are not developmental genetics at all, 00:10:31.520 --> 00:10:32.745 align:middle line:90% but population genetics. 00:10:32.745 --> 00:10:35.520 align:middle line:90% 00:10:35.520 --> 00:10:39.540 align:middle line:84% They deal most directly with the consequences of population 00:10:39.540 --> 00:10:42.095 align:middle line:84% changes and the frequency of different variants, 00:10:42.095 --> 00:10:46.500 align:middle line:84% or alleles, of given genes, not with the means 00:10:46.500 --> 00:10:50.370 align:middle line:84% by which these alleles shape or influence 00:10:50.370 --> 00:10:54.100 align:middle line:84% the biochemical pathways of developing individuals. 00:10:54.100 --> 00:10:57.630 align:middle line:84% And so a lot of times the criticisms 00:10:57.630 --> 00:11:00.390 align:middle line:84% that sociobiologists are genetic determinists 00:11:00.390 --> 00:11:02.580 align:middle line:84% about social behavior is because they 00:11:02.580 --> 00:11:05.490 align:middle line:84% don't distinguish between ultimate and proximate research 00:11:05.490 --> 00:11:05.990 align:middle line:90% in biology. 00:11:05.990 --> 00:11:08.760 align:middle line:90% 00:11:08.760 --> 00:11:20.890 align:middle line:84% And he considers that the main problem with these criticisms, 00:11:20.890 --> 00:11:25.550 align:middle line:84% especially the critics that argue in this extreme fashion. 00:11:25.550 --> 00:11:28.740 align:middle line:84% They say sociobiologists are talking 00:11:28.740 --> 00:11:31.780 align:middle line:84% about traits that are hereditary, fixed, inevitable, 00:11:31.780 --> 00:11:34.270 align:middle line:84% unchangeable except by future selection 00:11:34.270 --> 00:11:36.020 align:middle line:90% for hereditary alternatives. 00:11:36.020 --> 00:11:40.360 align:middle line:84% Well we know that that can't be true 00:11:40.360 --> 00:11:47.870 align:middle line:84% because of the nature of what we know about how genes influence 00:11:47.870 --> 00:11:48.370 align:middle line:90% behavior. 00:11:48.370 --> 00:11:53.780 align:middle line:90% 00:11:53.780 --> 00:11:55.780 align:middle line:90% But let me ask you about-- 00:11:55.780 --> 00:11:57.880 align:middle line:84% just leaving these slides for a minute-- 00:11:57.880 --> 00:12:00.900 align:middle line:84% what about these studies of the ethology, where 00:12:00.900 --> 00:12:06.490 align:middle line:84% they're dealing with, like the cat mating behavior, 00:12:06.490 --> 00:12:08.540 align:middle line:90% for example? 00:12:08.540 --> 00:12:12.040 align:middle line:84% And you can find relationships across species, 00:12:12.040 --> 00:12:14.800 align:middle line:84% and the behavior is almost identical in different groups. 00:12:14.800 --> 00:12:16.060 align:middle line:90% Is that not social behavior? 00:12:16.060 --> 00:12:19.030 align:middle line:84% And isn't it genetically determined? 00:12:19.030 --> 00:12:22.730 align:middle line:84% And I would argue that it certainly is. 00:12:22.730 --> 00:12:26.620 align:middle line:84% But there are many learned aspects as well. 00:12:26.620 --> 00:12:29.550 align:middle line:84% So you will find individual differences in a group, 00:12:29.550 --> 00:12:33.080 align:middle line:90% especially on the stimulus side. 00:12:33.080 --> 00:12:34.500 align:middle line:84% They develop different preferences 00:12:34.500 --> 00:12:38.200 align:middle line:84% and so forth, even when the motor side is fairly fixed. 00:12:38.200 --> 00:12:43.390 align:middle line:90% 00:12:43.390 --> 00:12:47.520 align:middle line:84% Then Alcott talks about this review done in 1998. 00:12:47.520 --> 00:13:00.710 align:middle line:84% So that was a long time after the books appeared in 1975. 00:13:00.710 --> 00:13:03.190 align:middle line:84% He called it the study of genetically determined 00:13:03.190 --> 00:13:03.860 align:middle line:90% social behavior. 00:13:03.860 --> 00:13:08.000 align:middle line:84% That was the main theme of the review. 00:13:08.000 --> 00:13:11.060 align:middle line:84% But Wilson actually devotes an entire chapter 00:13:11.060 --> 00:13:13.550 align:middle line:84% in his book to explain that although genes 00:13:13.550 --> 00:13:15.670 align:middle line:84% are essential for the development of behavior, 00:13:15.670 --> 00:13:19.630 align:middle line:84% they don't determine it by themselves. 00:13:19.630 --> 00:13:24.170 align:middle line:84% Of course, I think most people who look at genes in behavior 00:13:24.170 --> 00:13:26.450 align:middle line:84% now would say that that would have to be true. 00:13:26.450 --> 00:13:29.270 align:middle line:90% 00:13:29.270 --> 00:13:32.730 align:middle line:84% You can go to an extreme, like Richard Alexander did here. 00:13:32.730 --> 00:13:39.030 align:middle line:84% He just points out that genetic determinism 00:13:39.030 --> 00:13:43.180 align:middle line:84% is a ridiculous argument if you exclude environment completely, 00:13:43.180 --> 00:13:44.850 align:middle line:90% environment outside the DNA. 00:13:44.850 --> 00:13:46.790 align:middle line:84% Because it's always there, and there's always 00:13:46.790 --> 00:13:50.120 align:middle line:84% variables, which of course makes us 00:13:50.120 --> 00:13:53.450 align:middle line:84% wonder why the claim has been so persistent. 00:13:53.450 --> 00:13:56.890 align:middle line:90% So I'll deal with that next. 00:13:56.890 --> 00:14:00.600 align:middle line:84% But this is the way Alcock summarizes it, 00:14:00.600 --> 00:14:04.450 align:middle line:84% basically about, at least the chemical environment of the DNA 00:14:04.450 --> 00:14:05.550 align:middle line:90% is always involved. 00:14:05.550 --> 00:14:08.870 align:middle line:90% And that is [INAUDIBLE]. 00:14:08.870 --> 00:14:11.420 align:middle line:84% But I want to point out that a lot of people 00:14:11.420 --> 00:14:17.860 align:middle line:84% who argue against the influence of genes, 00:14:17.860 --> 00:14:19.940 align:middle line:84% they just feel that environment and learning 00:14:19.940 --> 00:14:23.940 align:middle line:84% are a lot more important, that you can discount 00:14:23.940 --> 00:14:26.480 align:middle line:90% a lot of the genetic factors. 00:14:26.480 --> 00:14:29.200 align:middle line:84% They also get upset by thinking about behavior 00:14:29.200 --> 00:14:31.590 align:middle line:90% in a totally deterministic way. 00:14:31.590 --> 00:14:33.980 align:middle line:84% They basically object to the basic assumption 00:14:33.980 --> 00:14:38.170 align:middle line:84% of a scientist, who's trying to explain 00:14:38.170 --> 00:14:41.680 align:middle line:84% physical causes of the effects of whatever they're 00:14:41.680 --> 00:14:44.800 align:middle line:84% investigating, whether its behavior or anything else. 00:14:44.800 --> 00:14:48.945 align:middle line:84% I mean psychologists can't do their work without assuming 00:14:48.945 --> 00:14:54.070 align:middle line:84% that there's specific effects on behavior, including 00:14:54.070 --> 00:14:56.570 align:middle line:90% genetic effects. 00:14:56.570 --> 00:14:59.130 align:middle line:84% And so there are people like that. 00:14:59.130 --> 00:15:02.470 align:middle line:84% They don't like, in general, the deterministic approach 00:15:02.470 --> 00:15:03.880 align:middle line:90% that scientists take. 00:15:03.880 --> 00:15:08.280 align:middle line:84% So a lot of times the criticisms of those people 00:15:08.280 --> 00:15:11.180 align:middle line:84% is much broader than just talking about sociobiology. 00:15:11.180 --> 00:15:14.538 align:middle line:84% But sociobiology is what triggers their ire 00:15:14.538 --> 00:15:15.330 align:middle line:90% more than anything. 00:15:15.330 --> 00:15:21.840 align:middle line:90% 00:15:21.840 --> 00:15:26.990 align:middle line:84% So this is an enduring myth, according to Alcock, 00:15:26.990 --> 00:15:29.140 align:middle line:84% despite the fact that all biologists 00:15:29.140 --> 00:15:31.460 align:middle line:84% know that every trait of every organism 00:15:31.460 --> 00:15:33.970 align:middle line:84% develops through this interaction of genes 00:15:33.970 --> 00:15:35.440 align:middle line:90% and environment. 00:15:35.440 --> 00:15:38.350 align:middle line:90% But I think the myth persists. 00:15:38.350 --> 00:15:41.880 align:middle line:84% They don't like this approach, as I just pointed out, 00:15:41.880 --> 00:15:43.700 align:middle line:84% for much more general reasons that have 00:15:43.700 --> 00:15:45.350 align:middle line:90% to do just with sociobiology. 00:15:45.350 --> 00:15:48.870 align:middle line:84% So this is a convenient straw man to set it up like that. 00:15:48.870 --> 00:15:51.970 align:middle line:84% I think it's the nature of human psychology. 00:15:51.970 --> 00:15:55.263 align:middle line:84% We believe in our ability to change our behavior, 00:15:55.263 --> 00:15:56.430 align:middle line:90% and other people's behavior. 00:15:56.430 --> 00:15:59.999 align:middle line:90% 00:15:59.999 --> 00:16:03.940 align:middle line:84% And for many people, the flexibility of human behavior 00:16:03.940 --> 00:16:08.140 align:middle line:84% is mistakenly taken as evidence that cultural factors 00:16:08.140 --> 00:16:10.480 align:middle line:84% are the only real determinants of our actions. 00:16:10.480 --> 00:16:13.780 align:middle line:84% In fact, in some of the meetings where these arguments have come 00:16:13.780 --> 00:16:18.500 align:middle line:84% up, people usually outside of sociobiology, 00:16:18.500 --> 00:16:23.520 align:middle line:84% of course, or behavioral biology, will argue that. 00:16:23.520 --> 00:16:26.730 align:middle line:84% Culture is the only real determinant of human behavior. 00:16:26.730 --> 00:16:29.530 align:middle line:90% 00:16:29.530 --> 00:16:32.210 align:middle line:84% And then I also feel that championing 00:16:32.210 --> 00:16:37.330 align:middle line:84% free will and freedom of action is pretty understandably 00:16:37.330 --> 00:16:38.770 align:middle line:90% very popular. 00:16:38.770 --> 00:16:42.430 align:middle line:84% In fact, I think humans have evolved 00:16:42.430 --> 00:16:44.800 align:middle line:84% an enthusiasm for freedom of action 00:16:44.800 --> 00:16:46.730 align:middle line:90% and a belief in free will. 00:16:46.730 --> 00:16:49.220 align:middle line:84% So I think we should be thinking like sociobiologists 00:16:49.220 --> 00:16:50.850 align:middle line:90% about that. 00:16:50.850 --> 00:16:54.100 align:middle line:90% Why does everybody feel that? 00:16:54.100 --> 00:16:56.870 align:middle line:84% I mean, yes, there are some intellectuals that take a very 00:16:56.870 --> 00:17:00.710 align:middle line:84% deterministic approach, and say, we think we have free will 00:17:00.710 --> 00:17:01.380 align:middle line:90% but we don't. 00:17:01.380 --> 00:17:02.720 align:middle line:90% And they're being philosophical. 00:17:02.720 --> 00:17:06.400 align:middle line:84% But in their own behavior, do they believe in free will? 00:17:06.400 --> 00:17:07.745 align:middle line:90% You bet. 00:17:07.745 --> 00:17:08.920 align:middle line:90% We all do. 00:17:08.920 --> 00:17:10.099 align:middle line:90% I think it's inherited. 00:17:10.099 --> 00:17:12.697 align:middle line:84% And I think it's adaptive to be that way. 00:17:12.697 --> 00:17:18.760 align:middle line:90% 00:17:18.760 --> 00:17:23.880 align:middle line:84% Can a difference in one allele change a behavior? 00:17:23.880 --> 00:17:27.859 align:middle line:84% And here's this interesting figure, 3.1, 00:17:27.859 --> 00:17:30.970 align:middle line:84% to explain how a difference in one allele-- 00:17:30.970 --> 00:17:34.601 align:middle line:84% and he has them represented by capital and small b-- 00:17:34.601 --> 00:17:38.080 align:middle line:84% could result in a behavioral difference between two adults. 00:17:38.080 --> 00:17:39.950 align:middle line:84% And it's a kind of multiplier effect. 00:17:39.950 --> 00:17:41.540 align:middle line:84% This is the way I've reproduced it. 00:17:41.540 --> 00:17:48.030 align:middle line:90% 00:17:48.030 --> 00:17:52.090 align:middle line:84% So you start with the fertilized egg. 00:17:52.090 --> 00:17:54.600 align:middle line:90% And here's one individual. 00:17:54.600 --> 00:17:59.780 align:middle line:84% Notice most of the genes are the same except this gene here. 00:17:59.780 --> 00:18:05.760 align:middle line:84% And this could be big B, little b. 00:18:05.760 --> 00:18:07.490 align:middle line:84% But it's different from this individual, 00:18:07.490 --> 00:18:10.750 align:middle line:84% who has the two recessive genes at the same locus. 00:18:10.750 --> 00:18:12.870 align:middle line:84% So his behavior, if it's going to be affected, 00:18:12.870 --> 00:18:17.420 align:middle line:84% will be any effect of that one allele. 00:18:17.420 --> 00:18:20.900 align:middle line:84% And this person doesn't even have that allele. 00:18:20.900 --> 00:18:24.090 align:middle line:84% So he's got to be affected by the other one. 00:18:24.090 --> 00:18:29.730 align:middle line:84% It's just one gene, so one protein. 00:18:29.730 --> 00:18:32.850 align:middle line:84% And that genetic difference, of course, 00:18:32.850 --> 00:18:34.333 align:middle line:84% will interact with the environment. 00:18:34.333 --> 00:18:35.875 align:middle line:84% And the environment can be different. 00:18:35.875 --> 00:18:38.550 align:middle line:90% 00:18:38.550 --> 00:18:40.550 align:middle line:84% So the effects, if the environment's different 00:18:40.550 --> 00:18:43.600 align:middle line:84% for these two individuals, you're going to get differences 00:18:43.600 --> 00:18:47.750 align:middle line:84% that affects the adult. But then as they develop, of course, 00:18:47.750 --> 00:18:51.500 align:middle line:84% and neurons develop, we know that there 00:18:51.500 --> 00:18:53.870 align:middle line:84% are many effects of environment on that that 00:18:53.870 --> 00:18:56.620 align:middle line:90% are independent of these. 00:18:56.620 --> 00:19:00.610 align:middle line:84% But that, in fact, this allele could make a difference 00:19:00.610 --> 00:19:02.800 align:middle line:84% in the way these things happen during development. 00:19:02.800 --> 00:19:09.420 align:middle line:84% So the effect here could be present throughout development 00:19:09.420 --> 00:19:13.925 align:middle line:84% with environments, as long as they're slightly different. 00:19:13.925 --> 00:19:15.550 align:middle line:84% It could lead to pretty big differences 00:19:15.550 --> 00:19:17.960 align:middle line:84% into adults, in spite of that allele. 00:19:17.960 --> 00:19:21.370 align:middle line:90% 00:19:21.370 --> 00:19:24.530 align:middle line:84% And yet, the differences developed specifically 00:19:24.530 --> 00:19:26.360 align:middle line:84% because of that one genetic difference. 00:19:26.360 --> 00:19:31.120 align:middle line:84% So that's all that we we're talking about here. 00:19:31.120 --> 00:19:33.980 align:middle line:84% So let's talk exactly how and why 00:19:33.980 --> 00:19:36.170 align:middle line:84% the relative frequency of the two alleles 00:19:36.170 --> 00:19:38.650 align:middle line:84% could change over multiple generations. 00:19:38.650 --> 00:19:43.100 align:middle line:84% Let's raise the possibilities from what we know. 00:19:43.100 --> 00:19:47.150 align:middle line:84% And these are the things I can think of. 00:19:47.150 --> 00:19:53.900 align:middle line:84% Why B could increase and the recessive trait could decrease. 00:19:53.900 --> 00:19:58.440 align:middle line:84% First of all, if the recessive trait resulted in death 00:19:58.440 --> 00:20:00.350 align:middle line:84% before the age of reproduction, more 00:20:00.350 --> 00:20:04.383 align:middle line:90% often than the dominant trait. 00:20:04.383 --> 00:20:06.050 align:middle line:84% I'm just going to refer to them that way 00:20:06.050 --> 00:20:11.040 align:middle line:84% because that's a common way of expressing 00:20:11.040 --> 00:20:15.180 align:middle line:84% for one allele, the recessive and dominant allele 00:20:15.180 --> 00:20:16.220 align:middle line:90% affecting that gene. 00:20:16.220 --> 00:20:18.740 align:middle line:90% 00:20:18.740 --> 00:20:21.670 align:middle line:84% A second thing could be B could result 00:20:21.670 --> 00:20:25.880 align:middle line:84% in behavioral difference, reduce the probability 00:20:25.880 --> 00:20:28.560 align:middle line:84% of successful reproduction in a particular environment, 00:20:28.560 --> 00:20:30.118 align:middle line:90% but not in all environments. 00:20:30.118 --> 00:20:31.910 align:middle line:84% So at least in that particular environment, 00:20:31.910 --> 00:20:35.190 align:middle line:84% the genes would change in their frequency. 00:20:35.190 --> 00:20:38.850 align:middle line:84% All we need is probability differences. 00:20:38.850 --> 00:20:42.100 align:middle line:84% And if the recessive trait resulted in no change 00:20:42.100 --> 00:20:45.590 align:middle line:84% in probability of reproduction, but it 00:20:45.590 --> 00:20:51.310 align:middle line:84% did reduce parental care, that alone, you see, would result-- 00:20:51.310 --> 00:20:54.720 align:middle line:84% because you would have, statistically anyway, 00:20:54.720 --> 00:20:58.280 align:middle line:90% less survival the offspring. 00:20:58.280 --> 00:21:01.190 align:middle line:84% And that would be enough then to lead 00:21:01.190 --> 00:21:03.320 align:middle line:84% to changes over multiple generations 00:21:03.320 --> 00:21:04.910 align:middle line:84% in the frequency of those two genes. 00:21:04.910 --> 00:21:09.950 align:middle line:90% 00:21:09.950 --> 00:21:13.430 align:middle line:84% So let's talk about breeding for behavioral traits. 00:21:13.430 --> 00:21:16.325 align:middle line:84% We know that animals are bred for physical traits. 00:21:16.325 --> 00:21:18.495 align:middle line:84% You know how dogs have been bred to look different. 00:21:18.495 --> 00:21:22.830 align:middle line:90% 00:21:22.830 --> 00:21:25.090 align:middle line:84% As we see especially in farm animals, 00:21:25.090 --> 00:21:29.450 align:middle line:84% we've bred beef cattle, so they're meatier. 00:21:29.450 --> 00:21:31.540 align:middle line:90% Well what about behavior? 00:21:31.540 --> 00:21:34.180 align:middle line:84% It's been done in the laboratory for a number 00:21:34.180 --> 00:21:37.030 align:middle line:84% of particular behavioral traits, where you ignore 00:21:37.030 --> 00:21:39.470 align:middle line:84% any physical differences and you only 00:21:39.470 --> 00:21:41.860 align:middle line:90% have a measure of behavior. 00:21:41.860 --> 00:21:45.250 align:middle line:84% For example, how loud crickets sing, 00:21:45.250 --> 00:21:47.560 align:middle line:84% and the ones that sing louder you 00:21:47.560 --> 00:21:49.650 align:middle line:90% can breed those with each other. 00:21:49.650 --> 00:21:53.960 align:middle line:90% The ones that sing less. 00:21:53.960 --> 00:21:56.523 align:middle line:84% And at the beginning, they're probably all singing. 00:21:56.523 --> 00:21:58.440 align:middle line:84% But some of them don't sing as loud as others. 00:21:58.440 --> 00:22:01.450 align:middle line:84% And if you keep breeding, you will eventually 00:22:01.450 --> 00:22:06.570 align:middle line:84% end up with a loud singing group and a pretty silent group. 00:22:06.570 --> 00:22:08.540 align:middle line:84% It's also been done with fruit flies. 00:22:08.540 --> 00:22:10.500 align:middle line:90% This has been the most common. 00:22:10.500 --> 00:22:13.440 align:middle line:84% And probably the most famous experiments with fruit flies 00:22:13.440 --> 00:22:15.880 align:middle line:84% are the production of learning mutants first produced 00:22:15.880 --> 00:22:18.230 align:middle line:84% by Chip Quinn of this department. 00:22:18.230 --> 00:22:21.630 align:middle line:84% Most of that work he did when he was at Princeton. 00:22:21.630 --> 00:22:26.350 align:middle line:84% And he produced strains of fruit flies 00:22:26.350 --> 00:22:29.470 align:middle line:84% that in a particular learning test that he had set up 00:22:29.470 --> 00:22:34.530 align:middle line:84% to screen the fruit flies, they were particularly stupid. 00:22:34.530 --> 00:22:36.380 align:middle line:84% And he named them after vegetables. 00:22:36.380 --> 00:22:41.790 align:middle line:84% So he has rutabaga, he has turnip, and such individuals. 00:22:41.790 --> 00:22:45.080 align:middle line:84% And he became well known for that work-- the learning 00:22:45.080 --> 00:22:47.450 align:middle line:90% mutants in fruit flies. 00:22:47.450 --> 00:22:54.300 align:middle line:84% It's also been done in mice and in rats. 00:22:54.300 --> 00:22:57.960 align:middle line:84% In mice they've produced spatial learning differences 00:22:57.960 --> 00:23:01.350 align:middle line:84% in different groups, and groups that differ in nest building 00:23:01.350 --> 00:23:02.160 align:middle line:90% activity. 00:23:02.160 --> 00:23:04.770 align:middle line:84% You just select the ones that are 00:23:04.770 --> 00:23:07.970 align:middle line:84% most vigorous about building big nests, 00:23:07.970 --> 00:23:10.030 align:middle line:84% and the one's that don't build such big nest, 00:23:10.030 --> 00:23:12.210 align:middle line:84% and don't nest in such a vigorous way. 00:23:12.210 --> 00:23:15.430 align:middle line:84% And if you breed them selectively 00:23:15.430 --> 00:23:16.940 align:middle line:84% for those behavioral traits, you'll 00:23:16.940 --> 00:23:21.140 align:middle line:84% eventually get groups that are very, very different 00:23:21.140 --> 00:23:22.760 align:middle line:90% in the way they build nests. 00:23:22.760 --> 00:23:25.320 align:middle line:84% And you can do the same thing for spatial learning problems. 00:23:25.320 --> 00:23:27.810 align:middle line:84% And there, the best known is the rat experiments, 00:23:27.810 --> 00:23:33.900 align:middle line:84% where they had what's called the Hebb-Williams maze. 00:23:33.900 --> 00:23:36.812 align:middle line:84% A fairly complex maze that they could change easily. 00:23:36.812 --> 00:23:38.770 align:middle line:84% They could change the problems so the rat would 00:23:38.770 --> 00:23:40.240 align:middle line:84% be trained on one, and then they'd 00:23:40.240 --> 00:23:44.710 align:middle line:84% change the barriers around and test them again, and do that 00:23:44.710 --> 00:23:45.330 align:middle line:90% repeatedly. 00:23:45.330 --> 00:23:48.110 align:middle line:84% And they'd come up with a measure of how intelligent-- 00:23:48.110 --> 00:23:51.870 align:middle line:84% it was called a rat intelligence test, how smart are they 00:23:51.870 --> 00:23:52.912 align:middle line:90% in learning mazes. 00:23:52.912 --> 00:23:54.870 align:middle line:84% And of course, some of them learned much better 00:23:54.870 --> 00:23:55.960 align:middle line:90% than others. 00:23:55.960 --> 00:23:58.080 align:middle line:84% And so again, we can selectively breed them 00:23:58.080 --> 00:23:59.720 align:middle line:84% for how well they learn the maze. 00:23:59.720 --> 00:24:02.390 align:middle line:84% We can have the ones to learn better. 00:24:02.390 --> 00:24:06.260 align:middle line:84% We'll interbreed those ones that learn more poorly. 00:24:06.260 --> 00:24:09.070 align:middle line:84% And you end up with a maze bright, maze dull strain. 00:24:09.070 --> 00:24:13.430 align:middle line:84% And then you can test for other differences, 00:24:13.430 --> 00:24:15.060 align:middle line:84% and what else happens to this animal? 00:24:15.060 --> 00:24:16.143 align:middle line:90% What happens in the brain? 00:24:16.143 --> 00:24:19.810 align:middle line:90% 00:24:19.810 --> 00:24:22.920 align:middle line:84% It was the fruit fly work that led most directly 00:24:22.920 --> 00:24:25.380 align:middle line:90% to neuroscience studies. 00:24:25.380 --> 00:24:27.900 align:middle line:84% In fact Chip, after he came here, 00:24:27.900 --> 00:24:33.020 align:middle line:84% eventually did zero in on a particular gene 00:24:33.020 --> 00:24:37.000 align:middle line:84% for a particular factor in the brain 00:24:37.000 --> 00:24:40.500 align:middle line:84% that was found by other groups also 00:24:40.500 --> 00:24:41.900 align:middle line:90% to be involved in learning. 00:24:41.900 --> 00:24:45.850 align:middle line:90% 00:24:45.850 --> 00:24:50.170 align:middle line:84% And when we deal with humans, the best studies probably 00:24:50.170 --> 00:24:54.450 align:middle line:84% that support genetic influences on behavior, 00:24:54.450 --> 00:24:57.210 align:middle line:90% are the twin studies. 00:24:57.210 --> 00:25:03.930 align:middle line:84% Do you all know the experiments studying concordance rates? 00:25:03.930 --> 00:25:05.980 align:middle line:84% First of all, you have to collect 00:25:05.980 --> 00:25:12.810 align:middle line:84% large numbers of identical twins so 00:25:12.810 --> 00:25:19.070 align:middle line:84% that you can either test them or find out a lot about them. 00:25:19.070 --> 00:25:22.550 align:middle line:84% For example, do they become schizophrenic? 00:25:22.550 --> 00:25:25.730 align:middle line:84% And so that's certainly a big behavioral difference, 00:25:25.730 --> 00:25:27.350 align:middle line:84% the ones that become schizophrenic 00:25:27.350 --> 00:25:28.880 align:middle line:90% and the one's that don't. 00:25:28.880 --> 00:25:34.550 align:middle line:84% So you find out, if one of the twins, you find out, 00:25:34.550 --> 00:25:37.980 align:middle line:84% is schizophrenic, what is the probability that his twin will 00:25:37.980 --> 00:25:38.930 align:middle line:90% have schizophrenia? 00:25:38.930 --> 00:25:42.680 align:middle line:84% Do you know difference what the probability is? 00:25:42.680 --> 00:25:45.510 align:middle line:90% It's about 2/3. 00:25:45.510 --> 00:25:48.620 align:middle line:90% So it's not totally genetic. 00:25:48.620 --> 00:25:53.430 align:middle line:84% And it's interesting that that 2/3 for schizophrenia 00:25:53.430 --> 00:25:57.480 align:middle line:84% also applies to the kind of diabetes I have. 00:25:57.480 --> 00:26:01.178 align:middle line:90% If I had a twin brother-- 00:26:01.178 --> 00:26:02.845 align:middle line:84% it would have to be a brother because it 00:26:02.845 --> 00:26:06.180 align:middle line:90% would have to be monozygotic-- 00:26:06.180 --> 00:26:08.460 align:middle line:84% the brother would have a 2/3 chance 00:26:08.460 --> 00:26:10.910 align:middle line:90% of having the same thing. 00:26:10.910 --> 00:26:14.660 align:middle line:84% The concordance rate is not 100%. 00:26:14.660 --> 00:26:18.860 align:middle line:84% So that just means there has to be environmental factors that 00:26:18.860 --> 00:26:21.620 align:middle line:90% also have a strong influence. 00:26:21.620 --> 00:26:28.580 align:middle line:84% And the degree to which the genetics and environment play 00:26:28.580 --> 00:26:33.620 align:middle line:84% roles can be estimated from just studying concordance rates. 00:26:33.620 --> 00:26:36.250 align:middle line:84% And that has been done for a number of different things. 00:26:36.250 --> 00:26:40.890 align:middle line:90% 00:26:40.890 --> 00:26:45.190 align:middle line:84% About the selected reading for behavioral traits, 00:26:45.190 --> 00:26:49.850 align:middle line:84% I like many of the examples in this book, by Temple Grandin. 00:26:49.850 --> 00:26:51.620 align:middle line:90% She's a very interesting lady. 00:26:51.620 --> 00:26:55.080 align:middle line:84% She's actually, I believe, come here to give a talk once, 00:26:55.080 --> 00:26:56.690 align:middle line:90% at least I've heard her. 00:26:56.690 --> 00:27:03.230 align:middle line:84% I think when I heard her she was promoting one of her books, 00:27:03.230 --> 00:27:06.340 align:middle line:84% probably this one, at the bookstore 00:27:06.340 --> 00:27:09.200 align:middle line:84% in Porter Square, where they get authors to come every week, 00:27:09.200 --> 00:27:13.580 align:middle line:84% and sometimes twice a week, to give talks on their new books. 00:27:13.580 --> 00:27:17.270 align:middle line:90% And I met her. 00:27:17.270 --> 00:27:19.950 align:middle line:84% I had a copy of her book, she signed it 00:27:19.950 --> 00:27:21.980 align:middle line:84% and talked to me about the teaching I 00:27:21.980 --> 00:27:23.990 align:middle line:90% was doing at MIT and so forth. 00:27:23.990 --> 00:27:25.690 align:middle line:84% Gave me permission, carte blanche, 00:27:25.690 --> 00:27:28.850 align:middle line:84% to use anything in her book in the class. 00:27:28.850 --> 00:27:34.280 align:middle line:84% So she points out various things the behavioral traits 00:27:34.280 --> 00:27:37.100 align:middle line:90% that dogs have been bred for. 00:27:37.100 --> 00:27:39.870 align:middle line:84% They've been bred, as you know, for herding ability-- 00:27:39.870 --> 00:27:43.350 align:middle line:90% for example, the sheep dog. 00:27:43.350 --> 00:27:46.070 align:middle line:84% If you want to herd sheep, and you really 00:27:46.070 --> 00:27:49.660 align:middle line:84% do need dogs to do it efficiently, 00:27:49.660 --> 00:27:52.690 align:middle line:84% you don't want to choose just any dog. 00:27:52.690 --> 00:27:55.560 align:middle line:84% No matter how smart he is, how loyal, 00:27:55.560 --> 00:27:57.940 align:middle line:90% they are genetically different. 00:27:57.940 --> 00:28:00.990 align:middle line:84% And they have been bred specifically for herding. 00:28:00.990 --> 00:28:05.890 align:middle line:84% So the sheep dog is very, very good. 00:28:05.890 --> 00:28:09.760 align:middle line:84% You're enhancing certain fixed action patterns 00:28:09.760 --> 00:28:13.870 align:middle line:84% and decreasing the influence of other fixed action patterns. 00:28:13.870 --> 00:28:21.730 align:middle line:84% In a way, you're enhancing detecting and stalking 00:28:21.730 --> 00:28:22.850 align:middle line:90% behavior. 00:28:22.850 --> 00:28:24.900 align:middle line:84% But you're inhibiting the later parts 00:28:24.900 --> 00:28:27.740 align:middle line:90% of the predatory behavior. 00:28:27.740 --> 00:28:29.390 align:middle line:90% They never attack the sheep. 00:28:29.390 --> 00:28:33.550 align:middle line:90% 00:28:33.550 --> 00:28:36.740 align:middle line:84% Predatory attack is also determined by multiple genes, 00:28:36.740 --> 00:28:39.360 align:middle line:90% or multiple components. 00:28:39.360 --> 00:28:42.030 align:middle line:84% It's not a single fixed action pattern, really, at least 00:28:42.030 --> 00:28:43.860 align:middle line:90% on the motor side. 00:28:43.860 --> 00:28:46.970 align:middle line:84% Then retrievers, same kind of thing. 00:28:46.970 --> 00:28:48.990 align:middle line:84% Some dogs are terrible retrievers. 00:28:48.990 --> 00:28:52.130 align:middle line:84% But if you get a golden retriever, or a Labrador 00:28:52.130 --> 00:28:57.870 align:middle line:84% retriever, very easy because it's part of their genetics. 00:28:57.870 --> 00:29:02.070 align:middle line:84% And of course their trained for hunting, pointing. 00:29:02.070 --> 00:29:04.970 align:middle line:84% I remember my father, who hunted pheasants, 00:29:04.970 --> 00:29:08.330 align:middle line:84% he had a pointer when I was a little kid. 00:29:08.330 --> 00:29:14.320 align:middle line:84% And I still remember that dog, because he was so incredibly-- 00:29:14.320 --> 00:29:17.100 align:middle line:84% not just so incredibly loyal to my father, and not to 00:29:17.100 --> 00:29:19.590 align:middle line:90% his kids-- 00:29:19.590 --> 00:29:22.740 align:middle line:90% he was so good at what he did. 00:29:22.740 --> 00:29:26.520 align:middle line:84% He would stay right at my father's side. 00:29:26.520 --> 00:29:30.110 align:middle line:84% I mean they're used for they're incredibly good senses, 00:29:30.110 --> 00:29:38.120 align:middle line:84% but also for their ability to detect the pheasant, 00:29:38.120 --> 00:29:44.750 align:middle line:84% and then stop and withhold their tendency to try to grab 00:29:44.750 --> 00:29:47.020 align:middle line:90% it and attack it themselves. 00:29:47.020 --> 00:29:49.430 align:middle line:84% Pheasants are mostly on the ground. 00:29:49.430 --> 00:29:52.720 align:middle line:90% They can fly to get away. 00:29:52.720 --> 00:29:55.685 align:middle line:84% So he would become rigid and go into this posture. 00:29:55.685 --> 00:29:58.190 align:middle line:90% It was very obvious. 00:29:58.190 --> 00:30:02.645 align:middle line:84% And then, little signal from my father, then the dog 00:30:02.645 --> 00:30:05.050 align:middle line:90% would rush forward. 00:30:05.050 --> 00:30:08.000 align:middle line:84% Not to try to kill the pheasant, but to flush him 00:30:08.000 --> 00:30:10.280 align:middle line:90% so he would fly up. 00:30:10.280 --> 00:30:13.530 align:middle line:84% Because people that hunt like this usually wait, 00:30:13.530 --> 00:30:15.080 align:middle line:84% if they can't shoot them in air-- 00:30:15.080 --> 00:30:16.920 align:middle line:84% they're not good enough shots for that-- 00:30:16.920 --> 00:30:22.120 align:middle line:84% then they don't succeed in getting the pheasant. 00:30:22.120 --> 00:30:23.980 align:middle line:84% And I remember the situation where there 00:30:23.980 --> 00:30:26.130 align:middle line:90% were two pheasants pulled up. 00:30:26.130 --> 00:30:29.500 align:middle line:84% And my father had a double barreled shotgun. 00:30:29.500 --> 00:30:31.580 align:middle line:90% And he got both pheasants. 00:30:31.580 --> 00:30:34.240 align:middle line:84% And then another little signal, out the dog 00:30:34.240 --> 00:30:36.420 align:middle line:90% went to retrieve them. 00:30:36.420 --> 00:30:38.010 align:middle line:84% So he could do both of these things, 00:30:38.010 --> 00:30:42.520 align:middle line:90% retrieving, pointing, hunting. 00:30:42.520 --> 00:30:46.060 align:middle line:84% And yet many, many breeds of animals, you cannot train them. 00:30:46.060 --> 00:30:48.750 align:middle line:84% In fact, they weren't very good with children. 00:30:48.750 --> 00:30:53.540 align:middle line:84% So as his kids started growing older 00:30:53.540 --> 00:30:59.530 align:middle line:84% he gave the pointer to a farmer who had a lot of space. 00:30:59.530 --> 00:31:02.862 align:middle line:90% We were now living in a town. 00:31:02.862 --> 00:31:05.320 align:middle line:84% When he did that hunting we were still outside of the town. 00:31:05.320 --> 00:31:08.950 align:middle line:84% But then he moved into the town so his kids could go to school, 00:31:08.950 --> 00:31:15.280 align:middle line:84% and got a dachshund, much better family dog. 00:31:15.280 --> 00:31:17.930 align:middle line:90% 00:31:17.930 --> 00:31:20.570 align:middle line:84% So that's the dog I became most familiar with as I 00:31:20.570 --> 00:31:21.920 align:middle line:90% was growing up. 00:31:21.920 --> 00:31:25.700 align:middle line:84% Farm animals we know have been bred very specifically not just 00:31:25.700 --> 00:31:29.560 align:middle line:84% for their physical nature, but you 00:31:29.560 --> 00:31:33.450 align:middle line:84% can't help but when you're breeding farm animals, 00:31:33.450 --> 00:31:38.020 align:middle line:84% you'll tend to choose the ones that aren't as aggressive. 00:31:38.020 --> 00:31:42.285 align:middle line:84% So aggression has been reduced in the cattle, for example. 00:31:42.285 --> 00:31:45.250 align:middle line:90% 00:31:45.250 --> 00:31:49.050 align:middle line:84% And the amount of meat they produce has been increased. 00:31:49.050 --> 00:31:52.600 align:middle line:84% For chickens, of course, it's egg laying ability. 00:31:52.600 --> 00:31:53.690 align:middle line:90% And that's been enhanced. 00:31:53.690 --> 00:31:56.790 align:middle line:90% 00:31:56.790 --> 00:32:00.280 align:middle line:84% They also breed chickens, of course, for meat. 00:32:00.280 --> 00:32:01.640 align:middle line:90% Bulls it's a little different. 00:32:01.640 --> 00:32:06.230 align:middle line:84% And you find bulls that are breeders at cattle firms in he 00:32:06.230 --> 00:32:08.540 align:middle line:90% US, where they breed cattle. 00:32:08.540 --> 00:32:12.060 align:middle line:84% Again, they choose bulls they have to limit their aggression. 00:32:12.060 --> 00:32:15.853 align:middle line:84% But you want big, meaty bulls because that's 00:32:15.853 --> 00:32:17.020 align:middle line:90% what you're trying to breed. 00:32:17.020 --> 00:32:22.140 align:middle line:90% 00:32:22.140 --> 00:32:24.680 align:middle line:84% My grandfather knew all about this kind 00:32:24.680 --> 00:32:26.650 align:middle line:84% of breeding of the bulls because I 00:32:26.650 --> 00:32:30.680 align:middle line:84% remember he wanted to let us see how he did it. 00:32:30.680 --> 00:32:33.852 align:middle line:84% And he went in on horseback and got a bull. 00:32:33.852 --> 00:32:35.310 align:middle line:84% And here comes the bull and we were 00:32:35.310 --> 00:32:36.930 align:middle line:90% all right there in the yard. 00:32:36.930 --> 00:32:40.040 align:middle line:90% Here comes this charging bull. 00:32:40.040 --> 00:32:45.180 align:middle line:84% You could imagine what we felt. Here's this charging bull. 00:32:45.180 --> 00:32:48.580 align:middle line:84% But the bull, well known to my grandfather, 00:32:48.580 --> 00:32:52.200 align:middle line:84% was not interested in kids at all. 00:32:52.200 --> 00:32:53.900 align:middle line:84% He was only interested in one thing, 00:32:53.900 --> 00:32:56.230 align:middle line:90% those females in the yard. 00:32:56.230 --> 00:32:59.112 align:middle line:84% So my cousin opened the gate, the bull 00:32:59.112 --> 00:33:02.050 align:middle line:84% ran through and immediately began 00:33:02.050 --> 00:33:06.110 align:middle line:84% soliciting the attentions of the females. 00:33:06.110 --> 00:33:08.820 align:middle line:84% But of course, if you're using the bulls for other things, 00:33:08.820 --> 00:33:11.810 align:middle line:84% like bullfighting, then you breed them differently. 00:33:11.810 --> 00:33:15.530 align:middle line:84% And there are bull breeders in Spain 00:33:15.530 --> 00:33:21.130 align:middle line:84% that specifically breed bulls for their ferocity in bull 00:33:21.130 --> 00:33:22.930 align:middle line:90% fighting. 00:33:22.930 --> 00:33:25.780 align:middle line:84% And we know, of course, we're more familiar with breeding 00:33:25.780 --> 00:33:26.550 align:middle line:90% of horses. 00:33:26.550 --> 00:33:30.300 align:middle line:84% And they've been bred for various things, for speed-- 00:33:30.300 --> 00:33:34.715 align:middle line:84% the Thoroughbred-- for herding cattle-- 00:33:34.715 --> 00:33:37.230 align:middle line:90% 00:33:37.230 --> 00:33:38.880 align:middle line:90% the quarter horse. 00:33:38.880 --> 00:33:41.130 align:middle line:84% They're actually faster than Thoroughbred 00:33:41.130 --> 00:33:43.270 align:middle line:90% for a quarter of a mile. 00:33:43.270 --> 00:33:45.940 align:middle line:84% But they can't keep up with the Thoroughbred in a longer race. 00:33:45.940 --> 00:33:49.740 align:middle line:90% 00:33:49.740 --> 00:33:51.590 align:middle line:84% So there are several breeds of horses. 00:33:51.590 --> 00:33:56.490 align:middle line:84% We know that workhorses tend to be bigger, meatier, stronger, 00:33:56.490 --> 00:33:57.710 align:middle line:90% but slower. 00:33:57.710 --> 00:33:59.780 align:middle line:84% But they're used to pull things-- 00:33:59.780 --> 00:34:03.150 align:middle line:84% pull wagons, pull plows, and so forth. 00:34:03.150 --> 00:34:06.660 align:middle line:84% Fewer of them now, but so some of them are still maintained. 00:34:06.660 --> 00:34:10.949 align:middle line:84% So very specific breeding for behavioral traits. 00:34:10.949 --> 00:34:14.320 align:middle line:84% So this question concerns the problems 00:34:14.320 --> 00:34:17.110 align:middle line:84% that often happen when animals are bred 00:34:17.110 --> 00:34:19.110 align:middle line:90% for a single physical trait. 00:34:19.110 --> 00:34:21.929 align:middle line:90% What happens to them? 00:34:21.929 --> 00:34:24.449 align:middle line:84% It's common for behavioral problems to appear. 00:34:24.449 --> 00:34:29.280 align:middle line:84% And this is discussed quite a bit in Temple Grandin's book. 00:34:29.280 --> 00:34:32.370 align:middle line:84% Her example I like was collie dogs, 00:34:32.370 --> 00:34:39.107 align:middle line:84% because when I was growing up I remember Lassie. 00:34:39.107 --> 00:34:40.940 align:middle line:84% I don't know if you even know who Lassie is, 00:34:40.940 --> 00:34:43.480 align:middle line:84% but that was a popular dog in Hollywood movies. 00:34:43.480 --> 00:34:47.130 align:middle line:90% 00:34:47.130 --> 00:34:52.469 align:middle line:84% Lassie grew up before this intense breeding 00:34:52.469 --> 00:34:56.719 align:middle line:84% in this period started to change the appearance of collies 00:34:56.719 --> 00:35:00.415 align:middle line:84% to make them have narrower an narrower skulls 00:35:00.415 --> 00:35:03.920 align:middle line:90% and emphasized the needle nose. 00:35:03.920 --> 00:35:08.300 align:middle line:84% So she said the result was brainless ice picks. 00:35:08.300 --> 00:35:09.715 align:middle line:90% Not like Lassie at all. 00:35:09.715 --> 00:35:12.220 align:middle line:90% 00:35:12.220 --> 00:35:14.040 align:middle line:84% And that's the danger if you just 00:35:14.040 --> 00:35:18.270 align:middle line:84% ignore behavior when you're breeding 00:35:18.270 --> 00:35:20.270 align:middle line:90% for a particular physical trait. 00:35:20.270 --> 00:35:22.410 align:middle line:84% And this is not the only example. 00:35:22.410 --> 00:35:25.740 align:middle line:84% Breeds of dogs have particular problems. 00:35:25.740 --> 00:35:27.930 align:middle line:84% Usually it's that they get certain diseases. 00:35:27.930 --> 00:35:31.130 align:middle line:84% Or Cocker Spaniels, for example, many of them 00:35:31.130 --> 00:35:33.410 align:middle line:90% get a type of epilepsy. 00:35:33.410 --> 00:35:36.250 align:middle line:84% That's certainly a major behavioral problem, 00:35:36.250 --> 00:35:39.635 align:middle line:84% behavioral disease they get because of this breeding 00:35:39.635 --> 00:35:40.510 align:middle line:90% for their appearance. 00:35:40.510 --> 00:35:44.300 align:middle line:90% 00:35:44.300 --> 00:35:48.230 align:middle line:84% So is it true that no genes for human behavior have been found? 00:35:48.230 --> 00:35:51.170 align:middle line:90% 00:35:51.170 --> 00:35:53.360 align:middle line:84% The argument was that we can dispense 00:35:53.360 --> 00:35:55.450 align:middle line:84% with the direct evidence for a genetic basis 00:35:55.450 --> 00:36:00.780 align:middle line:84% of human social forms in a single word, no evidence. 00:36:00.780 --> 00:36:04.300 align:middle line:84% And here's another quote from this book, called 00:36:04.300 --> 00:36:09.480 align:middle line:84% Not In Our Genes, by a Harvard professor, Lewonton, Rose, 00:36:09.480 --> 00:36:11.580 align:middle line:84% a British professor, and Kamin, I 00:36:11.580 --> 00:36:14.141 align:middle line:90% don't remember where he's from. 00:36:14.141 --> 00:36:17.150 align:middle line:84% He said , no one has ever been able to relate any aspect 00:36:17.150 --> 00:36:20.070 align:middle line:84% of human social behavior to any particular gene or set 00:36:20.070 --> 00:36:20.610 align:middle line:90% of genes. 00:36:20.610 --> 00:36:22.700 align:middle line:90% Is that true still? 00:36:22.700 --> 00:36:24.770 align:middle line:90% I don't think so. 00:36:24.770 --> 00:36:28.280 align:middle line:84% First of all, in your book there, Alcock just points 00:36:28.280 --> 00:36:30.730 align:middle line:84% out the absence of evidence isn't really 00:36:30.730 --> 00:36:32.890 align:middle line:84% evidence of absent, of non involvement 00:36:32.890 --> 00:36:34.245 align:middle line:90% of genes in social development. 00:36:34.245 --> 00:36:36.880 align:middle line:90% 00:36:36.880 --> 00:36:39.160 align:middle line:84% I guess it seemed to him that way, 00:36:39.160 --> 00:36:40.890 align:middle line:84% and that was the argument he made. 00:36:40.890 --> 00:36:43.060 align:middle line:84% But I would point out more recent evidence 00:36:43.060 --> 00:36:51.310 align:middle line:84% for specific genes we say for a social behavior. 00:36:51.310 --> 00:36:54.310 align:middle line:84% I want you to keep in mind that even though specific genes are 00:36:54.310 --> 00:36:58.870 align:middle line:84% being found, that are correlated with various social behaviors 00:36:58.870 --> 00:37:03.010 align:middle line:84% and especially behavioral problems, 00:37:03.010 --> 00:37:06.030 align:middle line:90% genes code for proteins. 00:37:06.030 --> 00:37:08.110 align:middle line:84% And if we look at these behaviors, 00:37:08.110 --> 00:37:11.400 align:middle line:84% these abnormalities in humans-- autism, schizophrenia, 00:37:11.400 --> 00:37:14.860 align:middle line:84% and other mental diseases, attention deficit hyperactivity 00:37:14.860 --> 00:37:18.160 align:middle line:84% disorder-- yes, there's genetic contribution to all of these. 00:37:18.160 --> 00:37:21.120 align:middle line:84% There's always multiple genes involved. 00:37:21.120 --> 00:37:22.940 align:middle line:84% Environmental effects are still strong. 00:37:22.940 --> 00:37:27.600 align:middle line:90% 00:37:27.600 --> 00:37:29.940 align:middle line:84% So how could a gene that has what 00:37:29.940 --> 00:37:32.750 align:middle line:84% appears to be maladaptive consequences 00:37:32.750 --> 00:37:35.220 align:middle line:84% be present in some animals or people today? 00:37:35.220 --> 00:37:38.210 align:middle line:90% Why wasn't it lost? 00:37:38.210 --> 00:37:39.640 align:middle line:84% It's about the first thing I asked 00:37:39.640 --> 00:37:42.980 align:middle line:90% when I got diabetes is age 24. 00:37:42.980 --> 00:37:45.350 align:middle line:90% What's this gene doing around? 00:37:45.350 --> 00:37:49.970 align:middle line:84% Shouldn't it have disappeared 1,000 years ago? 00:37:49.970 --> 00:37:52.170 align:middle line:84% First of all, it could be a recent mutation 00:37:52.170 --> 00:37:54.580 align:middle line:90% and will be lost. 00:37:54.580 --> 00:37:59.790 align:middle line:84% Or maybe it has its bad effects after reproduction. 00:37:59.790 --> 00:38:08.590 align:middle line:84% I said I got it at age 24, during the age of reproduction. 00:38:08.590 --> 00:38:11.410 align:middle line:90% Many effects do occur later. 00:38:11.410 --> 00:38:14.080 align:middle line:84% It may have affects only in certain environments. 00:38:14.080 --> 00:38:15.690 align:middle line:84% If I were in an environment I wasn't 00:38:15.690 --> 00:38:18.760 align:middle line:84% exposed to the same viruses, I may never gotten it. 00:38:18.760 --> 00:38:23.700 align:middle line:84% It's an autoimmune disease triggered by viruses. 00:38:23.700 --> 00:38:26.220 align:middle line:84% It's also of course because of modern medical treatments. 00:38:26.220 --> 00:38:29.150 align:middle line:84% But it's also-- remember genetic swamping. 00:38:29.150 --> 00:38:31.970 align:middle line:84% If you've forgotten what that is, go back and read it. 00:38:31.970 --> 00:38:36.400 align:middle line:84% It was in my notes, and you could find it also on the web. 00:38:36.400 --> 00:38:39.710 align:middle line:84% And then I'm posting these homework questions. 00:38:39.710 --> 00:38:42.030 align:middle line:84% It's already at the end of the class here. 00:38:42.030 --> 00:38:43.790 align:middle line:90% But I am willing to give you-- 00:38:43.790 --> 00:38:47.940 align:middle line:84% I want you to spend most of the time on this one. 00:38:47.940 --> 00:38:49.440 align:middle line:84% The others should be easier for you. 00:38:49.440 --> 00:38:52.190 align:middle line:84% If you have trouble with those, I'm happy to give you hints. 00:38:52.190 --> 00:38:53.632 align:middle line:90% I'm asking you to do these. 00:38:53.632 --> 00:38:56.090 align:middle line:84% They're similar to homework I gave last year because I want 00:38:56.090 --> 00:38:57.673 align:middle line:84% you to think about these things and be 00:38:57.673 --> 00:39:02.020 align:middle line:84% clear about the type of thinking you need to do. 00:39:02.020 --> 00:39:04.400 align:middle line:84% And this is the one that causes the most controversy. 00:39:04.400 --> 00:39:05.830 align:middle line:90% So think about that. 00:39:05.830 --> 00:39:09.240 align:middle line:84% And you can ask me about it on Friday, if you wish. 00:39:09.240 --> 00:39:11.970 align:middle line:84% And I'm happy to give you some suggestions. 00:39:11.970 --> 00:39:18.070 align:middle line:90%