9:59:59.000,9:59:59.000
It's 1878.

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Sir Francis Galton[br]gives a remarkable talk.

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He's speaking to the Anthropologic[br]Instisitute of Great Britain and Ireland.

9:59:59.000,9:59:59.000
Known for his pioneering work[br]in human intelligence,

9:59:59.000,9:59:59.000
Dalton is a brilliant polymath.

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He's an explorer,

9:59:59.000,9:59:59.000
and antrhopologist,

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a sociologist,

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a psychologist,

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and a statistician.

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He's also a Eugenist.

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In this talk,

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he presents a new technique

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by which he can combine photographs[br]and produce composite portraits.

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This technique could be used[br]to characterize different types of people.

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Dalton thinks that if he combines[br]photographs of violent criminals,

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he will discover the face of criminality.

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But to his surprise,

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the composite portrait that he produces

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is beautiful.

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Galton's surprising finding[br]raises deep questions.

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What is beauty?

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Why do certain configurations of line[br]and color and form excite us so?

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For most of human hisotiry,

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these questions have been approached[br]using logic and speculation,

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but in the last few decades,

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scientists have addressed[br]the question of beauty

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using ideas from evolutionary psychology[br]and tools of neuroscience.

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We're beginning to glimpse[br]the why and the how of beauty,

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at least in terms of what it means[br]for the human face and form.

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And in the process,

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we're stumbling upon some surprises.

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When it comes to seeing[br]beauty in each other,

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while this decision is certainly[br]subjective for the individual,

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it's sculpted by factors that contribute[br]to the survival of the group.

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Many experiments have shown

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that a few basic parameters contribute[br]to what makes a face attractive.

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These include averaging, symmetry[br]and the effects of hormones.

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And let's take each one of these in turn.

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Galton's finding

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that composite or average faces[br]are typically more attractive

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than each individual face[br]that contributes to the average

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has been replicated many times.

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This laboratory finding fits[br]with many people's intuitions.

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Average faces represent the central[br]tendencies of a group.

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People with mixed features[br]represent different populations,

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and presumably harbor[br]rare genetic diversity

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and adaptibility to the environment.

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Many people find[br]mixed-race individuals attractive

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and inbred families less so.

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The second factor that contributes[br]to beauty is symmetry.

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People generally find symmetic faces[br]more attractive than asymmetic ones.

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Developmental abnormalities[br]are often associated with asymmetries,

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and in plants, animal and humans,

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asymmetries often arise[br]from parasitic infections.

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Symmetry it turns out,

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is also an indicator of health.

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In the 1930s,

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a man named MAximallian Fector Rowis

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recognized the importance[br]of symmetry for beauty

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when he designed the beauty micrometer.

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With this device,

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he could measure minor, asymmetric flaws

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which he could then make up for[br]with products he sold from his company,

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named brilliantly after himself:

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Max Factor,

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which as you know is one of the world's[br]most famous brands for makeup.

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The third factor that contributes[br]to facial attractiveness

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is the effect of hormones.

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And here, I need to apologize[br]for confining my comments

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to heterosexual norms.

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But estrogen and testosterone[br]play important roles

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in shaping features[br]that we find attractive.

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Estrogen produces features[br]that signal fertility.

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Men typically find woman attractive

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who have elements of both[br]youth and maturity.

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A face that's too baby-like might[br]mean that the girl is not yet fertile,

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so men find women attractive

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who have large eyes, full lips[br]and narrow chins

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as indicators of youth,

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and high cheekbones as an[br]indicator of maturity.

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Now, testosterone produces features[br]that we regard as typically masculine.

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These include heavier brows,

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thinner cheeks

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and bigger, squared-off jaws.

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But here's a fascinating irony.

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In many species,

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if anything,

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testosterone suppresses the immune system.

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So the idea that testosterone-infused[br]features are a fitness indicator

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doesn't really make a whole lot of sense.

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Here, the logic is turned on its head.

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Instead of a fitness indicator,

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scientists invoke a handicap principle.

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The most commonly cited[br]example of a handicap[br]

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is a peacock's tail.

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This beautiful but cumbersome tail[br]doesn't exactly help the peacock

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avoid predators and approach peahens.

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Why should such an extravagant[br]appendage evolve?

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Even Charles Darwin,

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in an 1860 letter to Asa Gray wrote

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that the sight of the peacock's tail[br]made him physcially illl.

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He couldn't explain it with his[br]theory of natural selection,

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and out of this frustration,

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he developed a theory of sexual selection.

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On this account,

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the display of the peacock's tail[br]is about sexual enticement,

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and this enticement means[br]that it's more likely

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that the peacock will mate[br]and have offspring.

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Now, the modern twist on this[br]display argument

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is that the peacock is also[br]advertising its health to the peahen.

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Only especially fit organisms[br]can afford to divert resources

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to maintaining such[br]an extravagant appendage.

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Only espeically fit men can afford[br]the price that testorone levies

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on their immune system.

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And by anaology,

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think of the fact that only very[br]rich men can afford

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to pay more than $10,000 for a watch[br]as a display of their financial fitness.

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Now, many people hear these kinds[br]of evoulutionary claims

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and think they mean that we somehow[br]are unconciously seeking mates

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who are healthy,

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and I htink this idea[br]is probably not right.

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Teenagers and young adults are not[br]exactly known for making decisions

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that are predicated on health concerns.

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But they don't have to be,

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and let me explain why.

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Imaging a population in which people[br]have three different types of preferences:

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for green, for orange and for red.

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From their point of view,

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their preferences have nothing[br]to do with health,

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they just like what they like.

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But if it were also the case

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that these preferences are associated[br]with the different likelihood

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of producing offspring,

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let's say in a ration of three[br]to two to one,

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then in the first generation,

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there would be three greens[br]to two organges to one red,

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and in each subsequent generation,

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the proportion of greens increase

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so that intention rations 98 percent[br]of this population has a green preference.

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Now, scientists coming in[br]and sampling this population

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disover that green[br]preferences are universal,

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so the point about this little[br]abstract example

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is that while preferences for[br]specific phsyical features

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can be arbitrary for the individual,

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if those features are hertiable

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and they are associated[br]with a reproductive advangtage,

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over time,

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they become universal for the group.

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So what happens in the brain[br]when we see beautiful people?

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Attractive faces activate parts of our[br]visual cortex in the back of the brain.

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An area called the [fusiform gyrus][br]

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that is especially attuned[br]to processing faces,

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and an adjacent area called[br]the lateral occipidal complex

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that is especially attuned[br]to processing objects.

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In addition,

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attractive faces activate parts[br]of our reward and pleasure centers

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in the front and deep in the brain,

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and these include areas that have[br]complicated names,

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like the ventral staiatum,

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the orber frontal cortex

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and the ventrimedial prefontol cortex.

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Our official brain that is attuned[br]to processing faces

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interacts with our pleasure centers

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to underpin the experience of beauty.

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Amazingly, while we all[br]engage with beauty,

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without our knowledge,

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beauty also engages us.

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Our brains respond to attractive faces[br]even when we're not thinking about beauty.

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We conducted an experiement in which[br]people saw a series of faces,

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and in one condition,

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they had to decide if a pair of faces[br]were the same or a different person.

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Even in this condition,

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attractive faces drove neural activity[br]robustly in their visual cortex

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despite the fact that they were thinking[br]about a person's identity

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and not their beauty.

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Another group similarly found[br]automatic responses to beauty

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within our pleasure centers.

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So taken together,

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these studies suggest that our brain[br]automatically responds to beauty

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by linking vision and pleasure.

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These beauty detectors,

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it seems,

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ping ever time we see beauty[br]regardless of whatever else

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we might be thinking.

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We also have a beauty is good stereotype[br]embedded in the brain.

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Within the orber frontal cortex,

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there's overlapping neaural activity[br]in response to beauty and to goodness,

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and this happens even when people[br]aren't expllicitly thinking

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about beauty or goodness.

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Our brains seem to reflexively[br]associate beauty and good.

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And this reflexive association may be[br]the biologic trigger

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for the many social effects of beauty.

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Attractive people receive all kinds[br]of advantages in life.

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They're regarded as more intelligent,

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more trustworthy,

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they're given higher pay[br]and lesser punishments,

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even when such judgments[br]are not warranted.

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These kinds of observations reveal[br]beauty's ugly side.

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In my lab,

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we recently found that people with minor[br]facial anomalies and disfigurements

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are regarded as less good, less kind,

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less intelligent, less competent[br]and less hardworking.

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Unfortunately, we also have[br]a disfigured-is-bad stereotype.

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This stereotype is probably[br]exploited and magnified

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by images in the popular media

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in which facial disfigurement[br]is often used as a shorthand

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to make someone a villianous character.

9:59:59.000,9:59:59.000
We need to undersand[br]these kinds of implicit biases

9:59:59.000,9:59:59.000
if we are to overcome them,

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and aim for a society in which[br]we treat people fairly,

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based on their behavior and not[br]on the happenstance of their looks.

9:59:59.000,9:59:59.000
Let me leave you with one final thought.

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Beauty is a work in progress.

9:59:59.000,9:59:59.000
The so-called universal[br]attributes of beauty

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were selected for --

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during the almost two million[br]years of the [plystascne?]

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Life was nasty, brutish[br]and a very long time ago.

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The selection criteria for reproductive[br]success from that time

9:59:59.000,9:59:59.000
doesn't really apply today.

9:59:59.000,9:59:59.000
For example,

9:59:59.000,9:59:59.000
death by parasite is not one[br]of the top ways that people die,

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at least not in the[br]technologically-developed world.

9:59:59.000,9:59:59.000
From antibiotics to surgery,

9:59:59.000,9:59:59.000
birth control to invitrofertilization,

9:59:59.000,9:59:59.000
the filters for reproductive[br]success are being relaxed,

9:59:59.000,9:59:59.000
and under these relaxed conditions,

9:59:59.000,9:59:59.000
preference and trait[br]combinations are free to drift

9:59:59.000,9:59:59.000
and become more variable.

9:59:59.000,9:59:59.000
Even as we are profoundly[br]effecting our environment,

9:59:59.000,9:59:59.000
modern medicine and technological[br]innovation is profoundly effecting

9:59:59.000,9:59:59.000
the very essence of what[br]it means to look beautiful.

9:59:59.000,9:59:59.000
The universal nature of beauty is changing

9:59:59.000,9:59:59.000
even as we're changing the universe.

9:59:59.000,9:59:59.000
Thank you.

9:59:59.000,9:59:59.000
(Applause)