Okay, welcome back to An Introduction to Human Behavioral Genetics. This is the third module of the first lecture unit. And in this module what I'm going to do is actually give you my definition of what behavioral benetics is, the field is, and also provide an overview of what I'm hoping to accomplish in this eight week course. So this is my definition of behavioral genetics. It's the area of psychology that involves the use of genetic methodologies to study the nature and origins of individual differences in human and animal behavior. Although in this course we really will only focus on human behavior. There are three aspects of the definition I'd like to focus on. The first is that behavioral genetic involves the use of genetic methodologies. Behavioral genetics is really a field within psychology, it's not, I don't see it as a field within genetics, but what it's doing is it's taking genetic methodologies in an attempt to answer psychological questions. So one of the things that we'll do in this course is talk about specific genetic methodologies, the methodologies that behavioral geneticists use. Those methodologies might be traditional methodologies, like the use of twin, adoption and family studies. And those will be a focus of the second lecture unit. Increasingly, as you will learn, behavioral geneticists have moved beyond the traditional methodologies, although we certainly use those methodologies today. But have moved beyond the traditional methodologies to use and analyze DNA. And this is something that has really been enabled through the Human Genome Project. So in lecture, in lecture unit three we'll talk about DNA, the Human Genome Project and genes, and these new DNA-based methodologies. The second aspect of the definition I'd like to emphasize is that behavioral genetics is interested in individual differences. There are two ways we might think about genetics influencing our behavior. And those two ways are actually, are represented in two different sub-disciplines within psychology. Genetics might influence common psychological mechanisms that we all share by virtue of being humans. The way we perceive objects in space. The way we learn material. The way our memories work. How our basic emotions operate. The area of psychology that's interested in how genetics shapes these common psychological mechanisms or processes is called evolutionary psychology. We won't be talking about evolutionary psychology in this course. Rather what behavioral genetics is interested in is not so much the commonality in our psychological processes, but the differences among us. Why some of us suffer schizophrenia and others don't. The way some of us are extroverted while others are introverted. So behavioral genetics is interested in individual differences. In this course, it'd be difficult and, and probably a little tedious to go through a whole bunch of different psychological traits and talk about the behavioral genetic research on those traits. So what I've decided to do is focus on two paradigmatic psychological traits and how genetics has shaped our understanding of these traits. In the fourth unit we'll talk about schizophrenia, which I guess is also a psychiatric trait. As representative of behavioral genetic research, not only on a psychiatric trait but on the trait that's, essentially neither or, it's a diagnosis, you, you either have the diagnosis or you do not. The second trait that we'll focus on in Unit five is intelligence, or IQ. And this has generated a lot of controversy for the field of behavioral genetics. But it's certainly something worth our discussing. IQ, or intelligence is a representation of behavioral genetic research, not to an either/or trait but to a trait that's continuously distributed, or quantitative. The third aspect of the definition I'd like to focus on here is that what behavioral geneticists are interested in is using these methodologies to understand the origins of individual differences, their nature. One way we try to understand the origins of individual differences in behavior is calculating the heritability coefficient, something that we'll talk about in the third unit. It's a very controversial term within behavioral genetics, but we'll go through exactly how behavioral geneticists attempt to estimate the heritabliity and what they think the heritability tell us about individual differences in behavior. I think one misunderstanding of behavioral genetics that many people have is that what behavioral geneticists is about, or behavioral genetics is about is establishing that behavior is heritable. That our behavior is genetically influenced. I think of behavioral genetics as much more than that. Again, I think of it as using genetic methodologies to answer psychological questions. And sometimes those psychological questions don't deal with genetics, but rather deal with the environment. And in the seventh unit, what I'm going to do is talk about the use of genetic methodologies to not only tell us something about the genetic origins of behavior, but also about the environment, or the nurture side of behavior. And I think you'll find that behavioral genetic research has led to, or resulted in some very significant insights on the environmental side of the equation. Finally the last unit will be a wrap up unit, but I mostly want to try to touch on two things here, is how behavioral genetic research might, or is being applied. Applied in terms of a, a growing field of genomic or individualized medicine. To what extent can behavioral genetic research be used, or is it being used in our legal system? And then finally, what are the prospects going forward for this field of behavioral genetics? So that gives you hopefully an overview of how I see the field of behavioral genetics. And also how this course is organized, and what I'm hoping to achieve with you over the next eight weeks. Next time in the next lecture module we'll talk about a very famous twin study called the John/Joan case.