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Biological theory

Nature or Nurture? The Biologic Theory of Personality addresses the role evolution and biology play in our personality development. By Shreena Desai. . Created by Shreena Desai.

Video transcript

All right. Let's talk about yet another theory of personality called the biologic theory. But let me first start off by saying that there are many variations to this theory. Some relate more specifically to the brain. And others, like the evolutionary approach, the evolutionary psychology approach, is more concerned with behavior rather than traits. So for example, the evolutionary psychology theorizes that males and females have different mating strategies that influence the costs associated with passing on genetic material. For example, men have lots of sexual partners, but women are more selective due to the costs of pregnancy. Now, this case I just said is probably the most dominant psychological and biological theory to date. And Buss is one of the major psychologists associated with that. Now, taking all of this aside, the biologic theory suggests that important components of personality are inherited. So that's the key word. Important components are inherited or determined in part by our genes. And I'm not talking about those things we wear. But I'm talking about the things that are buried deep within our cell's nucleus. And to study biologic and genetic effects on personality, researchers always turn to look at twins, because twins studies are used in many psychological theories to tease out environmental versus genetic characteristics. Now, more specifically, they look at identical twins. And that's because they have the same genetic makeup. So that will eliminate one factor of variation. So they look at identical twins who were raised apart from each other or in different environments. Now, results showed that even though the twins were reared separately at an early age, they still had similar personalities. Certain traits that we give credit to the trait theory for categorizing were more influenced by heredity than others were. And one example is the social potency trait. And social potency is the degree to which a person assumes leadership and mastery roles in a social situation. So this was found to be common in both twins that were raised separately. And another trait, called traditionalism, which is the tendency to follow authority, was also shown to be common with both twins. But at the same time, there were other traits that had weaker genetic components. And some examples of this is the trait of achievement. It was stronger in one twin versus another. And same with closeness. So some researchers have even gone further to look at specific genes to try and relate to our personality. One example is that people with a longer dopamine-4 receptor gene are more likely to be thrill seekers. So basically, if you have this gene, you may love roller coasters and probably want to skydive one day. Hey, that sounds a lot like me. No. But don't think that just because you have a gene, you're destined to have that personality. We all know that. So just because you have a longer dopamine-4 receptor gene doesn't mean you will be a thrill seeker for sure. There are a lot of other things, such as environmental factors, that are coupled with genes that account for variation. Like looking back at this case of the identical twins. Obviously, there are parts of their personality that we can attribute to how they were reared and differences in their environment growing up. Now, another key word to know with this theory and many other theories is the word "temperament." Now, temperament is an innate disposition. And that's why I bring it up with the biologic theory, because of that word, "innate." Innate usually means brought up by genetics, or it's inherited. So temperament is anything from our mood to our activity level. And it's usually consistent throughout our life. And temperament is not solely just associated with the biologic theory. It's also associated with several other theories, including the trait theory. So biologic principles can underlie important concepts in many personality theories. So overall, the important takeaway of this tutorial is that our inherited genes, to some degree, lead to our traits, which then in turn lead to our behavior or our personality. But this isn't an end-all, be-all relationship. Our genes don't always determine our total personality. There has to be other things that account for this. And that includes environmental factors.