By Professor Robert Sapolsky
From time immemorial, the more philosophical among us have pondered: “What is the essence of who I am? What is it that has made me who I am?” Behavioral biology is the science of trying to figure this out, with the guiding assumption that an understanding of who and why we are cannot be achieved without considering our biology.
Now, a human asking these sorts of questions is more complicated, for a myriad of reasons, than a wildebeest asking, “Why is it in my essence to ovulate during one short period of time each year?” or a migratory bird wondering, “Why is it that each year I wish to fly from Tierra del Fuego to Alaska?” Tackling the biology of behavior is particularly daunting when considering humans and their social behaviors.
These challenges are even more extreme when considering an aspect of our behavior that is often the most interesting and important to study: What is the behavioral biology of our abnormal human behaviors? Because of the intrinsic intellectual challenge of a subject such as this, and because of its implication, when we ask a question about the biology of abnormal human behavior, we are often, de facto, asking: Whose fault is it that this has occurred; who should be held accountable? Multiple murderer: damaged frontal cortex or tainted soul? Spouse unable to get out of bed or go to work: victim of the neurochemistry of depression or self-indulgent slacker? Child failing at school: learning disabled or lazy?
This course is an introduction to the biology of human behavior, often of abnormal human behavior, with an emphasis on the brain. The purpose of the course is twofold: first, to teach the contemporary science of how our brains regulate our thoughts, emotions, and feelings—how our brains make us the individuals that we are—and second, to teach how our brains are regulated—sculpted by evolution, constrained or freed by genes, shaped by early experience, modulated by hormones. In this framework, the view is not of the brain as the be-all and end-all of what makes us individuals but, rather, the brain as the final common pathway, the conduit by which our individuality is shaped by biology that started anywhere from seconds to millions of years ago.
After an introductory lecture presenting this framework, a quarter of the course (Modules I and II) will be devoted to the functions of the nervous system. These lectures are updated versions of those in the first edition of this Teaching Company course and will start at the level of how a single neuron functions, building upward until we examine how millions of neurons in a particular region of the brain operate. The focus will be on the regions of the brain most pertinent to emotion and behavior, rather than, say, to regulation of kidney function.
The middle portion of the course (Modules III, IV, and V) will explore how the brain and behavior are regulated. First, we will cover how the brain regulates hormones and how hormones influence brain function and behavior. Then, we will examine how both the brain and behavior evolved, covering contemporary thinking about how natural selection has sculpted and optimized behavior and how that optimization is mediated by brain function. We will then focus on a bridge between evolution and the brain, namely, what genes at the molecular level have to do with brain function and how those genes have evolved.
Hormones, evolution, genes, and behavior, however, do not work in vacuo but, instead, are extremely sensitive to environment. The next section of the course (Module VI) examines ethology, which is the study of the behavior of animals in their natural habitats (rather than, for example, in a laboratory cage).
With these various approaches in hand, the final quarter of the course (Module VII) will examine how each approach helps explain an actual set of behaviors. Among a number of possible topics, we will focus on aggression, both because of the extensive information available and the importance of the subject.
The facts of this subject are not intrinsically difficult, even for the nonscientist. The implications, however, should seem far from simple. Yet this is a subject that each of us must master, because all of us are, de facto, behavioral biologists. We serve on juries, deciding whom to incarcerate, whom to put to death. We vote for elected officials who have stances regarding gun control and whether violence is inevitable, who determine whether certain types of love between consenting adults should be consecrated by the government imprimatur of marriage, who help decide whether a certain social problem can be fixed by government expenditures or is biologically irrevocable. And many (©2005 The Teaching Company Limited Partnership 1) of us will have to be behavioral biologists when confronting loved ones whose behaviors have changed them to an unrecognizable extent and deciding whether it is “them” or “their disease.”
The final lecture of this course will consider issues such as these: What are the societal and philosophical consequences of knowledge about the biology of our behaviors, the biology of what makes us the individuals that we are?