[MUSIC] So, welcome back. Let's get back to that question of why do we behave the way we do. And we're going to be talking a lot about stress again. Psychologists don't really do consensus, if they can help it, but in the case of personality traits it's hard to avoid openness to experience, conscientiousness, extroversion, agreeableness, and neuroticism. Called OCEAN for short, constitute the sum of human personality. Each of us has our own unique coordinates depending on precisely where we fall along each of these five dimensions. And loads of loads of studies have shown that where we fall in each dimension is about 50% genetic and 50% environmental. So what do you think is the major environmental influence on personality? If you said pen you should be way wrong. Some major studies suggested that they make a few percent of differences in personalities and behaviors is due to parental influences. And the effects of family largely disappear as people get older. So criminal parents they're most likely to produce criminal children. Yes, but not if they adopt the children. Likewise the children of divorced parents are more likely to get divorced. Yes, but only if they are biological children. So basically, these studies suggest that parents are overrated as shapers of values. Now, does that mean that parents are off the hook in relation to their children and they just let them play video games and eat what they want? No. Because parents control the happiness and well being of their children and the skills they grow up with. And how you treat your child is gonna effect the relationship you have with them. Just the way you treat your spouse effects the quality of your relationship with your spouse. And only a very naive newlywed thinks that you can shape the personality of your spouse. That doesn't mean you don't have to worry about how you treat them. Sandra Scarr, a champion of the idea that people pick the environment to suit their characters, puts it this way, parents' most important job is to provide support and opportunities, not to try and shape children's enduring personalities. And Matt Ridley, in his influential book, Nature Via Nurture says, Family is like vitamin C. You need some to stop you getting ill, but once you have it, consuming extra doesn't make you healthier. Say you've got a lazy child. You're not gonna be able to mold it in your image, but you might be able to help that child maximize his potential. Now, what I've just told you does not mean genetic determinism. It does not mean that whether a child is good or bad, intelligent or stupid, is gonna be solely down to genes. That's where the nature nurture arguments arise from, the mistaken belief that the parents are the sole environmental influence. They may not even be the most important part in terms of lasting impressions. There's peer culture and of course the culture as a whole. Any time children immigrate and successfully assimilate, they're obviously adapting to a new environment, which is not the parental environment, but the culture as a whole. So for example, if you're a first generation immigrant to a country you speak with you're parents accent or that of your school friends, your peers. You adopt the mannerisms of your peers. In the western world, at least, peers may be a lot more important than parenting. There are evolutionary reasons for this. Your peers will be your lovers, your allies, your rivals. In the long run, they're the ones who matter most. They matter more than your parents. You may have come across photos of Harry Harlow. He's a sober looking professor who studied the nature of love in his primary laboratory at Wisconsin. Google him for pictures. We can't use them here, cuz they're copyrighted. So Harlow raised infant rhesus monkeys on surrogate mothers that dispensed milk and their bodies made of either wire, mesh, or cloth. The surrogate-raised monkeys were socially and sexually immature. And they're dreadful mothers. What some psychiatrists such as John Bowlby and animal behaviorists such the Nobel prize winning Konrad Lorenz said that this proved that early contact with a real mother is necessary for emotional development. And this was called Attachment Theory. Actually, what Harlow showed was that monkeys' contact with peers is the key to emotional development, with the mother acting as go between. In that 2013 book, The Nature and Nurture of Love, Marga Vicedo shows how this discovery was ignored by Bowlby and Lorenz. And the stories it's been reported on are misrepresented. Vicedo, in a historian sense, is interested in how ethological thick theory, such as attachment, can grow, when evidence and logic are persuasively refuted. She's also interested in the motivation of the scientists who upheld it. So Bowlby and Lorenz were working in the Cold War era, and apparently they thought that emphasizing parental importance in gender roles would help safeguard family integrity. Which they linked to social stability in the struggle against communism. Well, really, it's hard to avoid pre-existing biases when interpreting the role of families and genes. The kind of questions these studies address and the geneticists asks are in the public eye. Questions about fate. Original sin of you like. Are you born good or evil? Are you born clever or stupid? Or does family and society determine these facts? These are scientific questions but it's very hard to disentangle them from people's passionate belief in one or another social political policy. In 1996 Hillary Clinton, wife of the American president, wrote a book called It Takes a Village. And it Clinton presents her vision for the children of America. She focuses on the impact individuals and groups outside the family have for better or worse on a child's well-being. In 2005, Senator Rick Santorum wrote a refute to Clinton's book. It Takes a Family. Conservatism in the common good. Both books give not the ability of children to make their own choices. The extended violent matters depends on the environment you're in. But an important and yet usually ignored point are that people are not passive recipients of environment. They'll pick an environment that suits them. It's a phenomenon called niche selection and it's fairly obvious that living things do it. Like this one, this woodpeckers picking wood, it's not picking rocks right. It's just the same with us. You may have heard of studies done by social anthropologists who have someone pretend to be dead. In a big city people are going to walk around him, ignore him. Someone pretending to be dead in their little village though, is soon gonna be surrounded by people. The smaller the village the nosier the hesitance. Now in the village in this picture, the impact of genes is gonna be small because you have a huge shared environment. Everybody knows you here. Everything you do has witnesses. You spend a lot of time conforming to other people's expectations. It might be so that you never become truly yourself. Well, that's why many people move into the cities. Where they can be much more anonymous. Where they'll find people with their own predilections. Well that's mate selection. So the role of genes in cities is going to be much greater. That same sort of progression happens as you age. When you're young, your subject to whims and moods of your parents, and everyone is bigger than you, and you have to conform to others. As you get older, you become more independent and the shared environment gets smaller. You become truly yourself as determined by your genes. That probably explains the observation that identical twins reared apart become more alike in personality and IQ, as I mentioned before, as they age. Now, the media often suggests that there are genes specifically for addiction or criminality and other behavioral traits. The results of many studies support the conclusion that these behaviors are heritable. However, please note, that is not because of a specific gene structure, criminality and addiction, or religious beliefs, or politics. They're the side effects of genes. So what is passed from parent to child is a tendency towards a group of behaviors in a particular environment. You don't have genes for addiction, but we do have genes leading to an impetuous and risk-taking and rebellious personality. And that's associated with drug taking. So for example, twin studies suggest that opinions on a long list of issue from religion, to gay marriage, to party affiliations, have a substantial genetic component. So Hillary Clinton and Rick Santorum may have written the politically slanted books they did because of their genetics. And neuroscientist have also gotten in the act showing that liberals and conservatives have different patterns of brain activity. Particularly involving the amygdala, the part of the brain that makes emotional responses. Now the idea that political view have a genetic component is now widely accepted enough to become a field of study with its own name, genopolitics. Now obviously there isn't a gene controlling how people answer political questionnaires. That would be absurd. It requires to show them lurking in the genome was a gene that lay dormant for millions of years waiting for party politics. And there aren't genes for hating gay marriage either. But there are personality traits that would likely lead to this belief, and those personality traits may be ancient, way older than modern humans. Large amount of research has shown that people's whose basic and emotional responses to threats are more pronounced, end up developing whole loads of right wing opinions. That there isn't a suggestion that their political opinions are directly controlled by genetics. Rather, the political opinions are believed to develop differently in people with different basic biology. Something like the size of a particular brain area or other strength fits connections with other brain regions is influenced by our genes. But the pathway from our DNA to the apparently simple variation in the brain region is one with many twists and turns, the opportunities for other genes and accidents of history to intervene. The idea that genes could influence political belief is hardly a surprise. It would be weird if there wasn't some sort of genetic influence. >> Yay.
