Serendip is an independent site partnering with faculty at multiple colleges and universities around the world. Happy exploring!

Mean Genes Book Commentary

Simone Shane's picture

At the very beginning of Terry Burnham and Jay Phelan’s intriguing book, Mean Genes , the reader is told to “consider this book an owner’s manual for your brain” that will help demystify our instinctual drives, opinions, and behaviors. The two authors attempt to outline how our genes, naturally selected through years of ancestral history, shape our behaviors. Specifically, this book closely examines biological and anthropological explanations for debt, overeating, drug addictions, risky decisions, insatiability, gender differences, beauty, infidelity, family ties, and friendships. The reason why this book can be considered handbook is because many of our instincts that proved vital to the survival of our ancestors are no longer useful in plentiful modern societies. Through an understanding of the bases of our drives, Burnham and Phelan hope that we can learn how to “trick our genes” and thus find ways to more easily adapt to the modern world. Yet, while this book makes assertion about the biological bases of our “mean” behaviors, it does not adequately address through what biological means we are able to “trick” our genes, leaving room for many questions.

Mean Genes tackles such questions as why it is so difficult for humans to save money and refrain from eating once full. Human genetics evolved in a world were the main currency was food—a resource that spoiled very quickly. Therefore, it was beneficial not to save resources for later, but eat them right away and keep them stored in the form of fat. This simple observation helps explain why humans are driven to spend their money immediately—they’re hardwired to think that it will spoil if not put to use. It also speaks to why humans overeat. If it is not certain when the next meal will come and it is not possible to save food to last a week, the best option is to eat as much as possible so that you could live off the stored energy in your fat cells. Our eating habits are indeed strongly influenced by our species’ previous food-scarce environment. We are descendants of those humans whose genes coded for neuropeptide Y, which causes strong carbohydrate cravings and, when we are undernourished, drives us to eat everything we can find.

Burnham and Phelan offer many other genetic reasons why we may go into debt or get fat in a modern society. Now, while I understand that human behavior traits fall in a standard distribution, or bell curve, with many people falling around the average and few at either extremes, the argument put forth by this book does not explain why the ancestors of those modern day people who naturally save their money and are uninterested in food (as well as those who do not have the other genetically driven traits described by this book, such as lust, beauty-sense, family allegiance, insatiable desires, and selfishly driven friendships) survived natural selection and were able to propagate these “nice” genes. Wouldn’t natural selection have pushed the average of the bell curve up further than it did?

The genetic influences on our behavior described in Mean Genes are indeed fascinating and laid out in a very fun and engaging manner. However, while the authors at times describe how these genes affect behavior by explaining neurotransmitters and hormones, they too often skip the intermediate step between genes and behavior—the brain. I began this book expecting to get a guide to the brain, as promised, but was sadly denied many details of how the genes affected brain functioning. While the omission of many of these details is probably useful for general readers, they left me curious for more information.

I was first drawn to this book largely due to class discussion from the beginning of the semester when we discussed the theories of duality and the brain and behavior as one. It was very difficult for many people to accept that the brain could cause all behavior, including agency and morality, and I was hoping that this book could provide evidence that these traits are indeed constructs of human neurobiology. Going by what Burnham and Phelan say, our genetically encoded instincts can help explain “amoral” behavior. The drive to propagate one’s genes or find a committed provider can explain why people cheat, even if it is not the reason the person began the affair. Gluttony is a relic from times when food was scarce, while greed is a genetic tool to ensure that we will always have enough resources. Friendships will last only as long as the benefits of the relationship outweigh the efforts they cost to maintain: our genes will be erasing all phone numbers once they find no benefit. Thus, because of our genes humans are all inherently glutinous, lustful, insatiable, nepotistic, and selfish.

But are all humans all these things? Indeed, at the end of most sections Mean Genes suggests tricks to control some of our genetic dispositions, such as putting your money in back accounts with high transaction fees and no ATMs to prevent yourself from spending too much or giving your loved ones many inexpensive gifts at sporadic times rather than few expensive ones on set dates to capitalize on the genes that become hugely happy when they get something that they do not expect. Are “nice” people just especially good at these tricks? Perhaps they’re just on the lower end of the bell curve of mean and these tricks just work better? Either way, there is still a major question: if genes control instinctual drives, what’s is keeping these drives in check?

Burnham and Phelan state in their conclusion that we have genes that also allow for free will and self-discipline. But wouldn’t self-disciplined humans have died out long ago by not acting selfish enough to steal resources, gluttonous enough remain nourished, and lustful enough to reproduce? Or perhaps all of our ancestors had self-discipline but rarely ever used it because of such dire environments. The fact of the matter is that humans have metacognitive abilities to analyze their instinctual behaviors and judge them as immoral. If we do have genes, and therefore corresponding neural correlates, that allow for free will and self-discipline, how did they evolve? In class, we discussed the I-function and it’s position in the neo cortex and, since metacognition is a part of the I-function, we can assume that it too is located in this region. Yet how was it developed? While Mean Genes professes to be an “owner’s manual to your brain,” it only tells half the story. It provides us with an interesting assessment of how our primal instincts are governed by biology, but not our self-check system, as it gives no explanation as to why we are capable of going against these drives. Perhaps a sequel entitled Good Genes is in order.



Burnham, T., Phelan, J. (2000). Mean Genes. New York: Cambridge, MA: Publishing.


Paul Grobstein's picture

genes and a "self-check system"

Sounds indeed like a sequel, focusing on the origins and significance of the I-function, would be a good idea.