WEBVTT 00:00:00.567 --> 00:00:05.098 In the 17th century, a woman named Giulia Tofana 00:00:05.098 --> 00:00:07.809 had a very successful perfume business. 00:00:07.809 --> 00:00:10.066 For over 50 years she ran it. 00:00:10.066 --> 00:00:12.851 It sort of ended abruptly when she was executed — (Laughter) — 00:00:12.851 --> 00:00:18.282 for murdering 600 men. You see, it wasn't a very good perfume. 00:00:18.282 --> 00:00:22.148 In fact, it was completely odorless and tasteless and colorless, 00:00:22.148 --> 00:00:25.472 but as a poison, it was the best money could buy, 00:00:25.472 --> 00:00:29.265 so women flocked to her in order to murder their husbands. NOTE Paragraph 00:00:29.265 --> 00:00:34.525 It turns out that poisoners were a valued and feared group, 00:00:34.525 --> 00:00:38.694 because poisoning a human being is a quite difficult thing. 00:00:38.694 --> 00:00:42.029 The reason is, we have sort of a built-in poison detector. 00:00:42.029 --> 00:00:45.293 You can see this as early as even in newborn infants. 00:00:45.293 --> 00:00:47.864 If you are willing to do this, you can take a couple of drops 00:00:47.864 --> 00:00:50.427 of a bitter substance or a sour substance, 00:00:50.427 --> 00:00:54.199 and you'll see that face, the tongue stick out, the wrinkled nose, 00:00:54.199 --> 00:00:57.071 as if they're trying to get rid of what's in their mouth. 00:00:57.071 --> 00:01:00.023 This reaction expands into adulthood and becomes 00:01:00.023 --> 00:01:03.543 sort of a full-blown disgust response, no longer just 00:01:03.543 --> 00:01:05.995 about whether or not we're about to be poisoned, 00:01:05.995 --> 00:01:08.952 but whenever there's a threat of physical contamination 00:01:08.952 --> 00:01:13.083 from some source. But the face remains strikingly similar. 00:01:13.083 --> 00:01:17.036 It has expanded more, though, than just keeping us away 00:01:17.036 --> 00:01:19.217 from physical contaminants, and there's a growing 00:01:19.217 --> 00:01:22.700 body of evidence to suggest that, in fact, this emotion 00:01:22.700 --> 00:01:25.742 of disgust now influences our moral beliefs 00:01:25.742 --> 00:01:29.638 and even our deeply held political intuitions. NOTE Paragraph 00:01:29.638 --> 00:01:33.274 Why this might be the case? 00:01:33.274 --> 00:01:36.269 We can understand this process by understanding 00:01:36.269 --> 00:01:39.419 a little bit about emotions in general. So the basic human emotions, 00:01:39.419 --> 00:01:42.614 those kinds of emotions that we share with all other human beings, 00:01:42.614 --> 00:01:45.415 exist because they motivate us to do good things 00:01:45.415 --> 00:01:47.726 and they keep us away from doing bad things. 00:01:47.726 --> 00:01:51.109 So by and large, they are good for our survival. 00:01:51.109 --> 00:01:53.918 Take the emotion of fear, for instance. It keeps us away 00:01:53.918 --> 00:01:56.422 from doing things that are really, really risky. 00:01:56.422 --> 00:02:00.262 This photo taken just before his death — (Laughter) — 00:02:00.262 --> 00:02:03.108 is actually a — No, one reason this photo is interesting 00:02:03.108 --> 00:02:06.725 is because most people would not do this, and if they did, 00:02:06.725 --> 00:02:08.725 they would not live to tell it, because fear would have 00:02:08.725 --> 00:02:12.400 kicked in a long time ago to a natural predator. 00:02:12.400 --> 00:02:16.007 Just like fear offers us protective benefits, disgust seems 00:02:16.007 --> 00:02:18.341 to do the same thing, except for what disgust does is 00:02:18.341 --> 00:02:20.936 keeps us away from not things that might eat us, 00:02:20.936 --> 00:02:23.601 or heights, but rather things that might poison us, 00:02:23.601 --> 00:02:26.198 or give us disease and make us sick. 00:02:26.198 --> 00:02:29.455 So one of the features of disgust that makes it such 00:02:29.455 --> 00:02:34.238 an interesting emotion is that it's very, very easy to elicit, 00:02:34.238 --> 00:02:37.121 in fact more so than probably any of the other basic emotions, 00:02:37.121 --> 00:02:39.490 and so I'm going to show you that with a couple of images 00:02:39.490 --> 00:02:41.373 I can probably make you feel disgust. 00:02:41.373 --> 00:02:44.568 So turn away. I'll tell you when you can turn back. 00:02:44.568 --> 00:02:45.701 (Laughter) NOTE Paragraph 00:02:45.701 --> 00:02:50.034 I mean, you see it every day, right? I mean, come on. (Laughter) NOTE Paragraph 00:02:50.034 --> 00:02:51.247 (Audience: Ewww.) NOTE Paragraph 00:02:51.247 --> 00:02:54.256 Okay, turn back, if you didn't look. NOTE Paragraph 00:02:54.256 --> 00:02:56.791 Those probably made a lot of you in the audience 00:02:56.791 --> 00:03:00.626 feel very, very disgusted, but if you didn't look, 00:03:00.626 --> 00:03:03.156 I can tell you about some of the other things that have been shown 00:03:03.156 --> 00:03:05.839 sort of across the world to make people disgusted, 00:03:05.839 --> 00:03:09.443 things like feces, urine, blood, rotten flesh. 00:03:09.443 --> 00:03:11.277 These are the sorts of things that it makes sense 00:03:11.277 --> 00:03:14.531 for us to stay away from, because they might actually contaminate us. 00:03:14.531 --> 00:03:16.826 In fact, just having a diseased appearance 00:03:16.826 --> 00:03:19.226 or odd sexual acts, these things are also 00:03:19.226 --> 00:03:22.217 things that give us a lot of disgust. NOTE Paragraph 00:03:22.217 --> 00:03:24.595 Darwin was probably one of the first scientists 00:03:24.595 --> 00:03:26.538 to systematically investigate the human emotions, 00:03:26.538 --> 00:03:30.227 and he pointed to the universal nature and the strength 00:03:30.227 --> 00:03:32.076 of the disgust response. 00:03:32.076 --> 00:03:35.347 This is an anecdote from his travels in South America. NOTE Paragraph 00:03:35.347 --> 00:03:37.083 "In Tierro del Fuego a native touched with his finger 00:03:37.083 --> 00:03:39.588 some cold preserved meat while I was eating ... 00:03:39.588 --> 00:03:43.107 and plainly showed disgust at its softness, whilst I felt 00:03:43.107 --> 00:03:46.105 utter disgust at my food being touched by a naked savage — (Laughter) — 00:03:46.105 --> 00:03:48.262 though his hands did not appear dirty." 00:03:48.262 --> 00:03:53.660 He later wrote, "It's okay, some of my best friends are naked savages." (Laughter) NOTE Paragraph 00:03:53.660 --> 00:03:56.404 Well it turns out it's not only old-timey British scientists 00:03:56.404 --> 00:03:58.685 who are this squeamish. I recently got a chance 00:03:58.685 --> 00:04:00.975 to talk to Richard Dawkins for a documentary, 00:04:00.975 --> 00:04:04.842 and I was able to disgust him a bunch of times. Here's my favorite. NOTE Paragraph 00:04:04.842 --> 00:04:07.207 Richard Dawkins: "We've evolved around courtship and sex, 00:04:07.207 --> 00:04:10.229 are attached to deep-rooted emotions and reactions 00:04:10.229 --> 00:04:14.929 that are hard to jettison overnight." NOTE Paragraph 00:04:14.929 --> 00:04:18.966 David Pizarro: So my favorite part of this clip is that 00:04:18.966 --> 00:04:21.609 Professor Dawkins actually gagged. 00:04:21.609 --> 00:04:25.194 He jumps back, and he gags, and we had to do it three times, 00:04:25.194 --> 00:04:28.750 and all three times he gagged. (Laughter) 00:04:28.750 --> 00:04:31.896 And he was really gagging. I thought he might throw up on me, actually. NOTE Paragraph 00:04:31.896 --> 00:04:35.112 One of the features, though, of disgust, 00:04:35.112 --> 00:04:38.042 is not just its universality and its strength, 00:04:38.042 --> 00:04:41.081 but the way that it works through association. 00:04:41.081 --> 00:04:44.816 So when one disgusting thing touches a clean thing, 00:04:44.816 --> 00:04:48.170 that clean thing becomes disgusting, not the other way around. 00:04:48.170 --> 00:04:51.377 This makes it very useful as a strategy if you want to 00:04:51.377 --> 00:04:53.143 convince somebody that an object or an individual 00:04:53.143 --> 00:04:56.811 or an entire social group is disgusting and should be avoided. 00:04:56.811 --> 00:04:59.352 The philosopher Martha Nussbaum points this out 00:04:59.352 --> 00:05:01.436 in this quote: "Thus throughout history, certain disgust 00:05:01.436 --> 00:05:04.677 properties -- sliminess, bad smell, stickiness, decay, foulness -- 00:05:04.677 --> 00:05:06.977 have been repeatedly and monotonously been associated with ... 00:05:06.977 --> 00:05:10.829 Jews, women, homosexuals, untouchables, lower-class people -- 00:05:10.829 --> 00:05:14.343 all of those are imagined as tainted by the dirt of the body." 00:05:14.343 --> 00:05:17.475 Let me give you just some examples of how, some powerful 00:05:17.475 --> 00:05:19.847 examples of how this has been used historically. 00:05:19.847 --> 00:05:23.437 This comes from a Nazi children's book published in 1938: 00:05:23.437 --> 00:05:26.247 "Just look at these guys! The louse-infested beards, 00:05:26.247 --> 00:05:29.557 the filthy, protruding ears, those stained, fatty clothes... 00:05:29.557 --> 00:05:32.323 Jews often have an unpleasant sweetish odor. 00:05:32.323 --> 00:05:35.116 If you have a good nose, you can smell the Jews." 00:05:35.116 --> 00:05:37.649 A more modern example comes from people who try to 00:05:37.649 --> 00:05:40.110 convince us that homosexuality is immoral. 00:05:40.110 --> 00:05:43.795 This is from an anti-gay website, where they said 00:05:43.795 --> 00:05:47.072 gays are "worthy of death for their vile ... sex practices." 00:05:47.072 --> 00:05:50.738 They're like "dogs eating their own vomit and sows wallowing in their own feces." 00:05:50.738 --> 00:05:53.482 These are disgust properties that are trying to be directly 00:05:53.482 --> 00:05:56.831 linked to the social group that you should not like. NOTE Paragraph 00:05:56.831 --> 00:05:59.603 When we were first investigating the role of disgust in 00:05:59.603 --> 00:06:03.472 moral judgment, one of the things we became interested in 00:06:03.472 --> 00:06:07.775 was whether or not these sorts of appeals are more likely 00:06:07.775 --> 00:06:10.840 to work in individuals who are more easily disgusted. 00:06:10.840 --> 00:06:12.969 So while disgust, along with the other basic emotions, 00:06:12.969 --> 00:06:15.585 are universal phenomena, it just really is true 00:06:15.585 --> 00:06:17.883 that some people are easier to disgust than others. 00:06:17.883 --> 00:06:19.569 You could probably see it in the audience members 00:06:19.569 --> 00:06:21.626 when I showed you those disgusting images. 00:06:21.626 --> 00:06:24.326 The way that we measured this was by a scale that was 00:06:24.326 --> 00:06:26.655 constructed by some other psychologists 00:06:26.655 --> 00:06:29.512 that simply asked people across a wide variety of situations 00:06:29.512 --> 00:06:31.613 how likely they are to feel disgust. 00:06:31.613 --> 00:06:33.406 So here are a couple of examples. 00:06:33.406 --> 00:06:35.578 "Even if I were hungry, I would not drink a bowl of my 00:06:35.578 --> 00:06:39.386 favorite soup if it had been stirred by a used but thoroughly washed fly-swatter." 00:06:39.386 --> 00:06:40.951 "Do you agree or disagree?" (Laughter) 00:06:40.951 --> 00:06:43.231 "While you are walking through a tunnel under a railroad track, 00:06:43.231 --> 00:06:46.895 you smell urine. Would you be very disgusted or not at all disgusted?" 00:06:46.895 --> 00:06:49.551 If you ask enough of these, you can get a general overall 00:06:49.551 --> 00:06:51.914 score of disgust sensitivity. 00:06:51.914 --> 00:06:54.387 It turns out that this score is actually meaningful. 00:06:54.387 --> 00:06:57.464 When you bring people into the laboratory and you ask 00:06:57.464 --> 00:07:01.293 them if they're willing to engage in safe but disgusting behaviors 00:07:01.293 --> 00:07:06.315 like eating chocolate that's been baked to look like dog poop, 00:07:06.315 --> 00:07:10.280 or in this case eating some mealworms that are perfectly healthy but pretty gross, 00:07:10.280 --> 00:07:13.271 your score on that scale actually predicts whether or not 00:07:13.271 --> 00:07:15.614 you'll be willing to engage in those behaviors. NOTE Paragraph 00:07:15.614 --> 00:07:18.212 The first time that we set out to collect data on this 00:07:18.212 --> 00:07:20.222 and associate it with political or moral beliefs, 00:07:20.222 --> 00:07:23.099 we found a general pattern -- 00:07:23.099 --> 00:07:26.401 this is with the psychologists Yoel Inbar and Paul Bloom -- 00:07:26.401 --> 00:07:30.421 that in fact, across three studies we kept finding 00:07:30.421 --> 00:07:32.942 that people who reported that they were easily disgusted 00:07:32.942 --> 00:07:36.397 also reported that they were more politically conservative. 00:07:36.397 --> 00:07:38.281 Another way to say this, though, is that people 00:07:38.281 --> 00:07:43.688 who are very liberal are very hard to disgust. (Laughter) NOTE Paragraph 00:07:43.688 --> 00:07:47.958 In a more recent follow-up study, we were able to look at 00:07:47.958 --> 00:07:50.639 a much greater sample, a much larger sample. In this case, 00:07:50.639 --> 00:07:53.231 this is nearly 30,000 U.S. respondents, 00:07:53.231 --> 00:07:56.008 and we find the same pattern. As you can see, 00:07:56.008 --> 00:07:57.953 people who are on the very conservative side 00:07:57.953 --> 00:08:00.655 of answering the political orientation scale are 00:08:00.655 --> 00:08:03.425 also much more likely to report that they're easily disgusted. 00:08:03.425 --> 00:08:05.920 This data set also allowed us to statistically control 00:08:05.920 --> 00:08:08.144 for a number of things that we knew were both related 00:08:08.144 --> 00:08:11.059 to political orientation and to disgust sensitivity. 00:08:11.059 --> 00:08:13.664 So we were able to control for gender, age, income, 00:08:13.664 --> 00:08:16.955 education, even basic personality variables, 00:08:16.955 --> 00:08:19.257 and the result stays the same. NOTE Paragraph 00:08:19.257 --> 00:08:22.683 When we actually looked at not just self-reported political orientation, 00:08:22.683 --> 00:08:25.583 but voting behavior, we were able to look geographically 00:08:25.583 --> 00:08:28.529 across the nation. What we found was that in regions 00:08:28.529 --> 00:08:32.426 in which people reported high levels of disgust sensitivity, 00:08:32.426 --> 00:08:34.413 McCain got more votes. 00:08:34.413 --> 00:08:37.531 So it not only predicted self-reported political orientation, 00:08:37.531 --> 00:08:39.903 but actual voting behavior. And also we were able, 00:08:39.903 --> 00:08:42.595 with this sample, to look across the world, 00:08:42.595 --> 00:08:46.189 in 121 different countries we asked the same questions, 00:08:46.189 --> 00:08:50.116 and as you can see, this is 121 countries collapsed 00:08:50.116 --> 00:08:52.486 into 10 different geographical regions. 00:08:52.486 --> 00:08:55.110 No matter where you look, what this is plotting is the size 00:08:55.110 --> 00:08:58.521 of the relationship between disgust sensitivity and political orientation, 00:08:58.521 --> 00:09:02.160 and no matter where we looked, we saw a very similar effect. 00:09:02.160 --> 00:09:05.597 Other labs have actually looked at this as well 00:09:05.597 --> 00:09:07.774 using different measures of disgust sensitivity, 00:09:07.774 --> 00:09:10.326 so rather than asking people how easily disgusted they are, 00:09:10.326 --> 00:09:12.666 they hook people up to physiological measures, 00:09:12.666 --> 00:09:14.294 in this case skin conductance. 00:09:14.294 --> 00:09:16.522 And what they've demonstrated is that people who report 00:09:16.522 --> 00:09:20.648 being more politically conservative are also more physiologically aroused 00:09:20.648 --> 00:09:24.222 when you show them disgusting images like the ones that I showed you. 00:09:24.222 --> 00:09:26.391 Interestingly, what they also showed in a finding 00:09:26.391 --> 00:09:30.416 that we kept getting in our previous studies as well 00:09:30.416 --> 00:09:34.163 was that one of the strongest influences here is that 00:09:34.163 --> 00:09:36.373 individuals who are very disgust-sensitive not only are 00:09:36.373 --> 00:09:38.459 more likely to report being politically conservative, but 00:09:38.459 --> 00:09:41.468 they're also very much more opposed to gay marriage 00:09:41.468 --> 00:09:43.617 and homosexuality and pretty much a lot of 00:09:43.617 --> 00:09:47.382 the socio-moral issues in the sexual domain. 00:09:47.382 --> 00:09:50.871 So physiological arousal predicted, in this study, 00:09:50.871 --> 00:09:52.569 attitudes toward gay marriage. NOTE Paragraph 00:09:52.569 --> 00:09:55.788 But even with all these data linking disgust sensitivity 00:09:55.788 --> 00:09:58.947 and political orientation, one of the questions that remains is 00:09:58.947 --> 00:10:02.018 what is the causal link here? Is it the case that 00:10:02.018 --> 00:10:05.292 disgust really is shaping political and moral beliefs? 00:10:05.292 --> 00:10:07.852 We have to resort to experimental methods to answer this, 00:10:07.852 --> 00:10:10.627 and so what we can do is actually bring people into the lab 00:10:10.627 --> 00:10:13.050 and disgust them and compare them to a control group 00:10:13.050 --> 00:10:15.458 that hasn't been disgusted. It turns out that over 00:10:15.458 --> 00:10:18.186 the past five years a number of researchers have done this, 00:10:18.186 --> 00:10:21.012 and by and large the results have all been the same, 00:10:21.012 --> 00:10:23.441 that when people are feeling disgust, their attitudes 00:10:23.441 --> 00:10:25.544 shift towards the right of the political spectrum, 00:10:25.544 --> 00:10:28.220 toward more moral conservatism as well. 00:10:28.220 --> 00:10:31.900 So this is whether you use a foul odor, a bad taste, 00:10:31.900 --> 00:10:37.190 from film clips, from post-hypnotic suggestions of disgust, 00:10:37.190 --> 00:10:39.556 images like the ones I've shown you, even just 00:10:39.556 --> 00:10:41.519 reminding people that disease is prevalent and they should 00:10:41.519 --> 00:10:45.158 be wary of it and wash up, right, to keep clean, 00:10:45.158 --> 00:10:47.938 these all have similar effects on judgment. NOTE Paragraph 00:10:47.938 --> 00:10:50.304 Let me just give you an example from a recent study 00:10:50.304 --> 00:10:53.264 that we conducted. We asked participants 00:10:53.264 --> 00:10:57.961 to just simply give us their opinion of a variety of social groups, 00:10:57.961 --> 00:11:02.373 and we either made the room smell gross or not. 00:11:02.373 --> 00:11:05.544 When the room smelled gross, what we saw was that 00:11:05.544 --> 00:11:09.215 individuals actually reported more negative attitudes toward gay men. 00:11:09.215 --> 00:11:11.438 Disgust didn't influence attitudes toward all the other 00:11:11.438 --> 00:11:13.831 social groups that we asked, including African-Americans, 00:11:13.831 --> 00:11:17.693 the elderly. It really came down to the attitudes they had 00:11:17.693 --> 00:11:19.086 toward gay men. 00:11:19.086 --> 00:11:22.647 In another set of studies we actually simply reminded people -- 00:11:22.647 --> 00:11:24.573 this was at a time when the swine flu was going around -- 00:11:24.573 --> 00:11:27.057 we reminded people that in order to prevent the spread 00:11:27.057 --> 00:11:30.775 of the flu that they ought to wash their hands. 00:11:30.775 --> 00:11:35.190 For some participants, we actually had them take questionnaires 00:11:35.190 --> 00:11:38.111 next to a sign that reminded them to wash their hands. 00:11:38.111 --> 00:11:40.631 And what we found was that just taking a questionnaire 00:11:40.631 --> 00:11:44.344 next to this hand-sanitizing reminder made individuals 00:11:44.344 --> 00:11:47.507 report being more politically conservative. 00:11:47.507 --> 00:11:49.544 And when we asked them a variety of questions about 00:11:49.544 --> 00:11:52.967 the rightness or wrongness of certain acts, what we also 00:11:52.967 --> 00:11:55.282 found was that simply being reminded that they ought 00:11:55.282 --> 00:11:58.591 to wash their hands made them more morally conservative. 00:11:58.591 --> 00:12:00.888 In particular, when we asked them questions about 00:12:00.888 --> 00:12:04.662 sort of taboo but fairly harmless sexual practices, 00:12:04.662 --> 00:12:07.288 just being reminded that they ought to wash their hands 00:12:07.288 --> 00:12:09.851 made them think that they were more morally wrong. 00:12:09.851 --> 00:12:12.251 Let me give you an example of what I mean by harmless 00:12:12.251 --> 00:12:15.016 but taboo sexual practice. We gave them scenarios. 00:12:15.016 --> 00:12:18.774 One of them said a man is house-sitting for his grandmother. 00:12:18.774 --> 00:12:21.492 When his grandmother's away, he has sex with his girlfriend 00:12:21.492 --> 00:12:22.840 on his grandma's bed. 00:12:22.840 --> 00:12:25.337 In another one, we said a woman enjoys masturbating 00:12:25.337 --> 00:12:29.231 with her favorite teddy bear cuddled next to her. (Laughter) 00:12:29.231 --> 00:12:31.863 People find these to be more morally abhorrent 00:12:31.863 --> 00:12:36.179 if they've been reminded to wash their hands. (Laughter) 00:12:36.179 --> 00:12:39.371 (Laughter) NOTE Paragraph 00:12:39.371 --> 00:12:42.900 Okay. The fact that emotions influence our judgment 00:12:42.900 --> 00:12:44.783 should come as no surprise. I mean, 00:12:44.783 --> 00:12:46.184 that's part of how emotions work. 00:12:46.184 --> 00:12:47.748 They not only motivate you to behave in certain ways, 00:12:47.748 --> 00:12:49.832 but they change the way you think. 00:12:49.832 --> 00:12:52.622 In the case of disgust, what is a little bit more surprising 00:12:52.622 --> 00:12:56.067 is the scope of this influence. It makes perfect sense, 00:12:56.067 --> 00:12:58.946 and it's a very good emotion for us to have, that disgust 00:12:58.946 --> 00:13:01.602 would make me change the way that I perceive 00:13:01.602 --> 00:13:04.645 the physical world whenever contamination is possible. 00:13:04.645 --> 00:13:07.577 It makes less sense that an emotion that was built 00:13:07.577 --> 00:13:10.483 to prevent me from ingesting poison should predict 00:13:10.483 --> 00:13:13.859 who I'm going to vote for in the upcoming presidential election. NOTE Paragraph 00:13:13.859 --> 00:13:16.667 The question of whether disgust ought to influence 00:13:16.667 --> 00:13:19.019 our moral and political judgments 00:13:19.019 --> 00:13:22.155 certainly has to be complex, and might depend on exactly 00:13:22.155 --> 00:13:24.837 what judgments we're talking about, and as a scientist, 00:13:24.837 --> 00:13:26.843 we have to conclude sometimes that the scientific method 00:13:26.843 --> 00:13:30.347 is just ill-equipped to answer these sorts of questions. 00:13:30.347 --> 00:13:32.395 But one thing that I am fairly certain about is, 00:13:32.395 --> 00:13:35.214 at the very least, what we can do with this research is 00:13:35.214 --> 00:13:38.066 point to what questions we ought to ask in the first place. 00:13:38.066 --> 00:13:42.066 Thank you. (Applause)