The Science of Human Behavior
Section 1: Introduction
Human behavior endlessly fascinates us. What drives our actions, thoughts, and feelings? Are we controlled by nature or nurtured by our environments? In this lecture, I will provide an introduction to the scientific study of human behavior and the various factors that influence why we act the way we do. We will explore the fields of evolutionary theory, molecular genetics, behavior genetics, ethology, neuroscience, and endocrinology. My goal is to give you the analytical tools to think critically about behavior and become informed behavioral biologists yourselves. This knowledge is highly relevant in daily life, from serving on a jury to understanding your own family.
Section 2: The Strange Case
Let's begin with a puzzle - the strange case of a man who suddenly begins acting aggressively and bizarrely out of character after years of normal behavior. One day at work, he violently punches someone in the face for no reason. What could explain this drastic change? I propose three possibilities: first, he has been harboring creepy tendencies all along. Second, he is having the most immature midlife crisis imaginable. Or third, he has developed a mutation in a single gene in his brain that is inducing aggression. This example demonstrates how our physiology and genetics can dramatically impact human behavior, even turning a normal person into a violent offender.
Section 3: Gauging Student Beliefs
To begin studying human behavior, we must examine our own innate beliefs and assumptions about what influences our actions. I polled the class about what percentage believed in various factors affecting behavior, from the genetic basis of sexual orientation to the ability for prenatal events to alter political views decades later. Surprisingly high percentages believed in genetic determinants, prenatal programming, the existence of God and souls, the presence of true evil in the world, and the reality of free will. In contrast, only a small fraction accepted evolution by natural selection. This informal survey reveals the incredible diversity in views we hold about human nature and behavior.
Section 4: The Common Thread
What could a woman's menstrual cycle, a brain tumor, the "Twinkie defense," and anabolic steroid use possibly have in common? Shockingly, all of these circumstances have been used successfully in courts of law to explain violent murderous behavior in individuals who supposedly lost control. This illustrates how changes to physiology and the body can dramatically alter brain function and resulting behavior. To understand why humans act the way we do, we must consider both the body and the brain.
Section 5: The Power of Categories
We as humans constantly place information into categories to interpret and simplify the complex world around us. Thinking in categories can illuminate understanding, as it allows easier storage of information and enables quicker evaluations. However, categorization can also distort understanding. We tend to underestimate differences between two facts in the same category, while overestimating differences between facts in different groupings. Categorization also discourages seeing the bigger picture, as focus narrows to the boundaries between categories. We must be cognizant of the pitfalls of categorical thinking when examining the nuanced drivers of human behavior.
Section 6: Color Perception as Category
Let's apply the concept of categories to the example of color perception. Visible light forms a continuous spectrum from violet to red, with infinite gradations between. But in an effort to store this information, our brain imposes boundaries on the spectrum to form discrete color categories. This affects memory - we are better at recalling a color we have seen if it falls in the center of a color range rather than at the edges. Differences in language also cause the rainbow to be divided differently, resulting in divergent color categorization across cultures. Thus, while categories shape cognition, variation exists in how they are constructed.
Section 7: Drawbacks of Categorization
More broadly, the categories we form from the chaos of information shape how we think about and process the world. Thinking in categories aids our memory and facilitates quicker evaluations. However, an over-reliance on categories carries many drawbacks. We tend to underestimate differences between two facts falling within the same category, while exaggerating small differences between facts residing across category boundaries. Focusing too much on boundaries makes us miss underlying similarities. Avoiding rigid categorical thinking and embracing nuance is crucial for properly understanding the drivers of human behavior in all their complexity.
Section 8: Evolutionary Theory
With these conceptual groundrules established, we now delve into our first knowledge category - evolutionary theory. This week focuses on introducing key concepts from evolution that will repeatedly reappear throughout the course. For those students less familiar with evolutionary principles, I highly encourage attending the catch-up sections led by our extraordinarily knowledgeable teaching assistants. Grappling with and internalizing the fundamentals of evolutionary theory is absolutely essential for comprehending the myriad biological factors underpinning our human patterns of behavior.
Section 9: Embracing Chaos
I have assigned the seminal book Chaos by acclaimed science writer James Gleick. This paradigm-shifting work challenges reductionist views in science by demonstrating through chaos theory that the behaviors of complex systems cannot be understood by simply breaking them down into component parts and then attempting to reassemble the whole from these fragments. Like the weather, behavior is an emergent phenomenon - more than the mere sum of its pieces. Since college, this brilliant book has most profoundly shaped my own thinking about the practice of science and avoidance of reductionism when studying the dynamics of living systems.
Section 10: Online Resources
I have provided extensive online resources for enrichment, including lecture materials, Q&A forums, and more. Readings will also all be downloadable PDFs rather than a traditional printed reader. My team and I are exerting great efforts to enable access to these materials even for non-enrolled students through the course website. Please take full advantage of these resources to supplement your studies and immerse yourself in the content. The more deeply you engage, the more profoundly this course will transform your thinking.
Section 11: Course Logistics
Turning now to logistics - smaller discussion sections will begin meeting this Thursday once we dive into the content. My office hours will start next week if you need one-on-one help. The midterm exam will take place in the evening of May 3rd, and that class time will be used for review. The final exam is scheduled for June 4th. While long form essays would be ideal, the large class size necessitates primarily multiple choice questions. The midterm will focus on mastering the fundamentals of each field we cover, while the final will concentrate on integrative, interdisciplinary thinking. Please check the course website for additional details.
Section 12: Conclusion
In summary, this class will introduce the many interacting variables - evolution, genetics, physiology, culture, environment - that drive the variability we see in human behavior. We will grapple with the pitfalls of categorical thinking and reductionism while exploring the fascinating, emerging science of behavioral biology. My aspiration is that you leave equipped with the analytical skills to parse the incredible complexity of human behavior through an integrated, nuanced lens. We have only glimpsed the tip of the iceberg - are you ready to dive deeper? Let the adventure begin.