Who you end up in a relationship with might have more to do with your genes than your personal preferences says one Central Michigan University professor.

Wiline Pangle of the Department of Biology studies the relationship between animal behavior and environmental conditions.

At CMU, the behavioral ecologist teaches courses pertaining to animal behavior, evolution and ecology. She also teaches general biology classes for biology majors and non-majors.

Every spring around Valentine’s Day, Pangle lectures students in her non-major biology class about the science of love.

Pangle sat down with Central Michigan Life to discuss the biology of love and attraction.

CM Life: What is the most important thing we should know about attraction?

Pangle: We don’t pick as freely as we might think. We are the product of natural selection, so we are pre-programmed to do what has worked in the past. We think we choose our partners because they are nice or funny, but we also choose them because they smell good and have a different immune system from us.

The reason we find someone attractive may be more based on biology and natural selection than we may think.

What makes someone

attractive?

In humans, we have what are called “honest cues” of reproduction. These honest cues are representative of your reproductive system’s success. If you are fertile, you will have cues of fertility.

We play a game with students and have them look at four photos of the same man, slightly modified, and have them choose which one is most attractive. They almost always mimic the research that’s been done and choose the face with the most testosterone.

We also have them look at two photos of the same woman, one of which was taken while she was ovulating, the other when she was not.

It’s a very subtle difference, but 90 percent of the students pick the ovulating photo.

Why are we attracted to these cues?

There’s something about features that we subconsciously choose because they worked for our predecessors. We’re hard-wired to pick up on these cues. We have no idea why we choose the photo we do. We think we are picking a mate because of choice, when really we are influenced by all sorts of things in our subconscious.

What are some other cues?

Hip-to-waist ratio, smells or symmetry of the face are thought to be most important. There is some data on breast size, which suggests having bigger breasts means you’re more reproductive.

What role does smell play?

There have been experiments where people wore the same T-shirt for a whole weekend without showering or cleaning it. Then, they had people of the opposite sex smell a bunch of these shirts and choose which one they liked best. There are a couple things that are cool about these experiments, such as:

• If you put a parent-child pair in the mix, the smell is repulsive for them, which is a way to avoid inbreeding. This is the same with siblings.

• Women who are ovulating are by far the most picked T-shirts. We don’t know how we detect ovulation, it’s just something that smells good.

• Another interesting trend is the more different our immune system is from the person who wore the shirt, the more attracted we are to the smell. This makes sense because in the grand scheme of things, you want your kid to get different immune systems from parents, so they are protected from as much stuff as possible.