It was on a trip to New York City when University of Michigan researcher Dan Kruger just happened to glance at the tabloid that inspired his recent study on men’s bachelor behavior.

On the cover, a Godzilla-scaled woman threatened to take over the city, a symbol of how greatly single ladies outnumbered single guys in the city.

For the professor who studies evolutionary links to human behavior, it sparked the question: Besides the obvious, why do guys seem to play the field so much longer when they live in cities with much larger female populations? It’s just one of the practical questions Kruger has looked into as an assistant professor in U-M’s Prevention Research Center of Michigan.

At the center, he’s studied everything from why school children live riskier lives when they live in dangerous neighborhoods to why some men use flashy cars and electronics to earn more sexual partners.

While some of the subjects he’s chosen to look into are out of pure academic curiosity, he said he decided to use his background in psychology and interest in Charles Darwin’s evolution theories to ultimately improve public health.

“I look at how to improve health in communities using science and specifically, evolutionary theory to better understand health patterns.”

One of his more recent studies is looking what might be causing a trend among women who live in dilapidated neighborhoods to have children prematurely or with low birth weights. Another is why humans react the way they do in response to the economic downturn.

At least part of the answer, Kruger said, can be found in evolution. Here are some excerpts from a recent conversation with him: Q: How do you find these health patterns? A: “We are looking at blood lead levels of children in Flint. One of the way kids get lead in their systems is from lead paint that’s peeling on older structures … We can use geographic information systems to map housing stock by census block groups and see a link.”

Q: Describe your more recent “bachelor” study. In your findings, why did guys tend to play the field more? A: “When there are more women in an area than men, the guys don’t feel as much of a push to settle down because their opportunities are plentiful. When there are fewer women compared to men, (the men) realize women there are scarce and are more likely to look to create commitments … When you look at the roles women play in reproduction, they have a much bigger cost and are motivated to be much more choosy in investing in a guy that will stick around. For guys, there is a greater payoff in reproductive success by having multiple partners.”

Q: You can’t mean that people really are always thinking about “reproductive success” when their looking for potential dates? A: “We’re not always consciously aware of or focusing on these things. People aren’t always focusing on having sex because they’re thinking ‘Oh, I want to have offspring’ … We are (psychologically) motivated by these desires, motivations and behaviors that influence reproductive success. Sex is enjoyable. If it wasn’t, we would be at the risk of dying off. We’re built to seek these things. It’s like our preferences for foods that are sweet, salty and fatty fast food marketers know this well … It helps to have the motivations to lead our behaviors because these were adaptive behavior patters for our ancestors.”

Q: Your perspective is largely coming from evolutionary theory? Do you often find people who beg to differ? A: “There’s a lot of different ways can disagree because they don’t behave in evolution in the first place … And we wouldn’t want to think were slaves to our genes and in a sense, it’s not like we’re hypnotized, but we are influenced … As an example, I hear so many young women who are 18, 19, 20-years-old who say I’m never having kids. But ten years later, they have a kid and love it. Then they claim they’ve never known love until having their child or they find they love them even more than their husband. So there’s this disconnect between our awareness of these things and our ultimate outcomes.”

Q: What are you studying next? A: “One of the big topics for our current research is the effect the economic climate has had on the health of people in our community. What I suspect is the degree of economic stress will be related to physical stress.”

Tina Reed covers health and the environment for AnnArbor.com. She can be reached at 734-623-2535 or tinareed@annarbor.com.