Journalist in Residence

Our Microbial Minds: How Microbes Make Us Human

PI(s): Carrie Arnold (Freelance writer (Williamsburg, VA))
Start Date: 7-Apr-2013
End Date: 27-Apr-2013

Trillions of microbes live in and on the human body, outnumbering our cells by ten to one. In recent years, microbiologists, geneticists, and evolutionary biologists have begun rigorously studying the human microbiome, attempting to identify the various bacterial species that occupy our bodies. They have found that microbes affect our body weight, the subtle scent we emit, our choice of mates, and how we behave.

Far from being just tiny hangers-on, a small but growing group of scientists are finding that these microbes are actually a potent driving force in evolution and speciation. Humans are no exception to the strong and occasionally bizarre effects of symbiotic microbes.

One relatively unexplored area of the effects of the microbiome is in the field of human behavior. It turns out that certain pathogens may trigger schizophrenia, autism, anorexia nervosa, and obsessive-compulsive disorder. They may also explain why some people love to race motorcycles while others of us prefer a tranquil walk in the woods.

Disruptions of the bacteria living in our intestines can alter anxiety and depression symptoms. Gut flora also help process sex hormones, and changes to these microbes alters who we mate with. Microbes living on our sweat glands process the chemicals we secrete, giving us our own individual perfume. This, too, affects mate selection.

My project at NESCent will examine the strange and profound ways microbes affect human behavior, and through that, human evolution.