The Differences Between Men and Women: Paul Zak at TEDxAmsterdamWomen

hello it's so great to be here are the biological differences between men and women besides our genitals we know that we interesting valuable biological differences so this is not a topic I ever wanted to study I want to avoid that topic of a household full of women believe me I don't want to talk about this topic except I spent 10 years running experiments in my laboratory try to understand why people behave in a good way a moral way or an evil way and guess what I found a lot of bad boys not that many bad girls and I really want to know why and honestly it's really fun to be a bad boy I started jumping out of airplanes recently man that's fun it's really fun you get to be a superhero for like a minute while you're skydiving so I said you know I should study this question so began looking at a variety of ways that men and women are different behaviorally I don't know what's in your heart but I can measure the underlying neurobiology that can drive some of these differences and I think some of the things we found may surprise you so first interesting fact all the humans start out on the female body type we all start out as women pretty interesting so you're a little embryo in about four weeks you're a little fetus and then if you have a Y chromosome you start making testosterone and you sexually differentiate except sometimes you don't and when you don't is really interesting so you know what happens if you do but when you don't something unusual happens so it turns out that testosterone which we think of as the prototypical Mayer homo male hormone so stay with virility and power is actually very impotent it's bound up in this little shell and it can't get into his receptor it doesn't do any good it's about 2% of testosterone is free free testosterone runs around guess and receptor has an effect the rest of it impotent so it turns out that Nature has given us a workaround for this impotent tosser own and it's called important word 5 alpha reductase what is that it's a little hormone a little enzyme that attacks testosterone and frees it up but it takes off a couple parts of it and turns it into high-octane testosterone which is called big word dihydrotestosterone DHT let's call it DHT so DHT is a stuff that really makes males different than females so males have 5 to 10 times more testosterone than females and as DHT is responsible for vocal cord deepening and muscle growth and hairiness if you get too much your hair falls out milk's males get male pattern baldness women don't get that very often okay so DHT it's the stuff except when it's not so it turns out there are two isolated villages in the world one in Honduras and one in Mexico in which perhaps by magic when some girls turn 12 they turn into boys why is this happen because these are isolated villages a lot of cousins married cousins and there's a recessive gene to make 5 alpha reductase and if you get two copies of the recessive gene your testosterone is all bound up so when these little kids are born they look like girls physically they look like girls but then they hit puberty 12 years old and they get a surge of testosterone because actually have a Y chromosome and now all that testosterone floating around some of that free testosterone gets into receptors and the genitals descends the vocal cords get deeper and those girls are into boys now here's what's interesting about this in these two isolated villages separately they both develop rituals around this oh you're one of those special things we're gonna have a giant party in the village you learn those very important people who change genders they're very sought after as marriage partners they can reproduce normally they can have children they're the most special people in the world because they got to change okay now there's a conflict in this if you instead have two X chromosomes and a Y you get an extra chromosome then you're kind of in bad shape so now you're a have Z right so you have male genitals but you also have breasts and now you don't know what you're doing these individuals called Klinefelter syndrome they tend to be mildly mentally they're generally sterile they have generated gender gender identity issues all the time and they don't have very pleasant lives because nature really didn't work out this system very well for them so that's a whole different ballgame quite rare but when it happens it's unfortunate okay so I started studying the bad boys because I've been doing experiments for ten years on what one of my colleagues said was known to be only a female hormone oxytocin so oxytocin classically is associated with birth and breastfeeding and yet in the animal literature for animals that live together there was many findings suggesting that both male and females of social animals release oxytocin to identify safety or familiarity says oh that's that nice little rodent that I'm living with I release oxytocin and I'll affiliate with it I will live together we'll live in the world together so I said maybe humans do this I was interested in this good and bad behavior maybe it's oxytocin that motivates us to be moral to treat each other well to be generous kind compassionate so it turns out that oxytocin is very hard to measure that's why no one had the crazy idea like I did to study this before it's a very shy little molecule you have to sort of provoke it to come out of the brain and then capture it really fast before it disappears but once we solved that technical problem we've run studies Belling in the lab but in the field they'll tape a couple of those in a second to identify how oxytocin works the brain circuit it activates what turns it on what turns it off and in ten years with their experiments we found a couple interesting things one is that oxytocin is released for a whole variety of pots behaviors essentially oxytocin encapsulate the Golden Rule if you're nice to somebody and they know it their brain releases oxytocin and motivates them to be nice to you we studied this allowed by using monetary transfer someone shares money with you you really saucy doesn't your share back with them someone hugs you touches you you release oxytocin you want to be nice back to them great way to connect so in all these experiments we found that in men and women oxytocin motivated positive social behaviors what we call moral behaviors right so we have a moral molecule that's really exciting but interestingly in every experiment I've run in ten years women always release more oxytocin than men and they're subsequently more trustworthy more generous more compassionate more empathic women are nicer than men now you know why except guess what anybody when they're ovulating ever cry at movies a lot estrogen makes you super sensitive to to oxytocin so when your estrogen is high like when you're ovulating oh you're so sensitive to everybody around you positive and negative and this is part of our biology you want to be more sensitive when you're ovulating you want to make sure that guy next to you really is the guy you want to be with right I'm going to be much more careful when you potentially could get pregnant so women you guys are more nicer than we are you're also more complicated and that's why we love you so much right so interestingly I'll take a clap for that is fine thank you in addition remember our friend testosterone very potent oxytocin inhibitor so in experiments when people instead of cooperating say sharing money when people don't cooperate this is done by computer you don't see anybody so someone just doesn't want to play nice with you men but not women get this big spike in testosterone the impotent kind and the high-octane kind and what do they do they have an aggressive response they want to enforce the rules and if they want to beat you up as well right women don't get this hot physiologic response so we talk to him in these experiments who people don't cooperate with they say I don't like it wasn't friendly wasn't wasn't nice but they don't want to go kill the other person so women are calmer I think women are going to make better negotiators they don't take it personally guys take it personally this guy didn't cooperate with me I'm gonna find him so no no it's anonymous experiment you can't do that it's okay all right so isn't this great and this is I think counter to our intuition right we think a women is more emotional in fact in many cases not they don't have this hot fizzy lock for physiologic response they don't have to protect their space they can affiliate better they connect better and it's a part of our biology isn't that great okay here's a hard one IQ guess what no difference on average but there is a difference in the distribution most women are closer to the average IQ for men many more dullards and many more geniuses why would that be the case because of you guys because what's the sexiest thing on a guy ladies his brain come on you love the sexy for smart guys don't you alright so because women are the primary choosers when it comes to sexual reproduction brains are sexy brains give you more resources brains means you can survive and you're not as stupid as all the other guys or jumping out of airplanes sorry that perpetuates that we want higher you know super crazy genius males but there's a he's a cost evolution there's no free lunch how do you get more super smart males you generate a whole bunch of really bad versions who are super dumb okay so that's part of this sexual selection model which is very interesting okay last topic the argument center right when you argue with your boyfriend husband right what does he always say why are you bringing up that stuff from 10 years ago right okay and this is very interesting it turns out that if you take the human brain and you watch it evolve from age zero up to age 25 and just map out the areas in the brain that grow more rapidly than the rest of the brain you find great differences in males and females and the number one difference we find in females is an area the brain in from the ear is called the hippocampus that generates long-term memory you guys have a bigger hippocampus than males do you remember things better so you do remember what we discussed 10 years ago we don't what's the area that grows fastest for males an area also in from the ears called the amygdala which is associated with emotion and aggression and fear ah that's what we do that's what we do best we can't do other things but we have this area which that's hyperactive in males okay so please forgive your spouse your boyfriend if he doesn't remember what you said ten years ago our brains aren't set up for that okay so what's the punchline here I think we should have a great sense of acceptance it's very hard to study neuroscience and not have an understanding of in some sense how similar we are in body types and brains but also how every brain is different and those differences sometimes cross on gender levels sometimes they cross on whether I have 5 alpha reductase and sometimes they're just random but I think coming to a notion of acceptance for differences as one of the wonderful parts of life is a great way to appreciate both the men and the women in our lives okay guys you can read more here thank you so much for listening

Channel: TEDx Talks

Views: 472,972

Keywords: tedx talk, tedx talks, ted, ted talk, ted x, ted talks, tedx

Id: VFL9Kc_eQpU

Length: 13min 1sec (781 seconds)

Published: Wed Dec 05 2012