Mean Genes

In their psychology book, Mean Genes: From Sex to Money to Food: Taming Our Primal Instincts (2000), Terry Burnham and Jay Phelan look at why we want to do so many things that are bad for us, and what forces drive our basic instincts. Mean Genes received a positive reception from critics and psychologists. Burnham is a well-known economist who focuses on the evolutionary and biological foundations for human behavior. Phelan is a biologist who taught biology at UCLA. Mean Genes is their first book together.

Burnham and Phelan attempt to answer two basic questions. The first is why we deliberately do things that we know we shouldn’t do, such as spending a whole paycheck in one go. The second question is whether it is possible to control our urges to lead better lives. We cannot reform our behavior without first understanding what drives it.

According to Burnham and Phelan, we can blame our ancestral DNA for our irresponsible behavior. It all comes down to how we lived in the past, in a hunter-gatherer world. Our ancestors struggled to survive. They fought for food, shelter, and safety. For example, they couldn’t store food outside the body, so they ate everything they could and stored it as body fat. These same instincts drive us nowadays—we just express them differently because society is very different.



Although most of us have access to enough food, we still overconsume because our base instincts tell us to store energy. Many of us have access to enough money, but we don’t save any of it, because again, our instincts tell us to splurge and buy everything we think we need right now. We end up carrying excess body weight and buying far more goods than we will ever need because biology makes us do it.

The same can be said for sex, according to Burnham and Phelan. Our genes cannot survive unless we reproduce. They live on in future generations. Our bodies, then, tell us to have as much sex as possible to increase our chances of reproduction. That is why there is less focus on marriage nowadays and more focus on casual, short-term relationships.

Although we overconsume, overspend, and overindulge, few of us are happy, claim Burnham and Phelan. This is because our DNA isn’t concerned about our happiness. It is only concerned about our immediate survival. Therefore, we can overeat and store body fat to keep us alive, and we can have lots of casual sex to up our chances of procreating, but we are unhappy inside.



The upside is that we are not slaves to our DNA or genetic code. According to Burnham and Phelan, we can override these base instincts to take back control of our lives. This will help our genes evolve, giving future generations the skills to take only what they need without overconsuming everything. Essentially, that is how evolution works—we adjust to our environment.

The first thing we must do is to recognize the role hormones and chemicals play in our day-to-day behavior. When we indulge in something thrilling, such as rollercoaster rides, or we eat nice food, our brains give out a reward response. This reward response feels good, and so we keep looking for ways to trigger it. The problem is that we look for these triggers in the wrong places.

Burnham and Phelan use the example of dopamine and nicotine. Dopamine is a happy hormone. This hormone is produced when we do something good for us, such as eating. Nicotine mimics dopamine in the human body. Our brain then recognizes nicotine as a good thing, and so we keep smoking even if it is terrible for us. We have evolved to look for short-term pleasure in everything without caring about our long-term survival.



Burnham and Phelan also examine why we indulge in risk-taking behavior, such as gambling, thrill seeking, and adventure. Men tend to indulge in more risks than women, and so there must be a reason for this. The answers are not found in hormones but in evolutionary biology.

In prehistoric times, men wanted to be strong and powerful. Men who put themselves in danger, such as killing a predator or fending off a rival clan, attracted more women. Risky behavior increased their chances of procreating. That is why we still see so much risk-taking behavior among men today.

We can override the effects of hormones by understanding them. Since we know why we crave life-shortening substances such as nicotine and alcohol, we can avoid them. Our brains then stop associating these substances with happiness. We can reprogram our bodies to stop looking for so much sugar, salt, and other unhealthy foods.



As for taking risks, there is no longer any need for men—or women—to put themselves in harm’s way. Instead, we should look for stability. For example, rather than gambling money away, we should save and invest it, and then we will always have resources available in times of hardship. It is up to us to help DNA evolve.