Sometimes the ways in which our brains shape behavior are just amusing, and sometimes our mental workings have serious effects on physical and social health. It’s always useful to have a clue what’s going on and why.

I’ll tell you about some interesting recent research that holds lessons for taking care of our minds, our bodies and our society. Most of the behaviors in the studies are affected in some way by our perceptions.

People keep spreading germs around by taking hand-washing lightly, maybe because it’s too simple a thing to take seriously. Despite years of cajoling, study after study, year after year finds Americans lacking in hand hygiene.

Some people don’t wash their hands very often, and a new study from Michigan State University found that even when people do wash after using the bathroom, only 5 percent washed long enough to get rid of most of the germs on them.

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It takes 15-20 seconds of hearty washing to get clean, but researchers said the average is about six seconds. Men were much worse than women.

In that light, another story is no surprise. Researchers at the University of California, Irvine tested basketballs and volleyballs and found them coated with disease-causing germs. You can bet the rest of the gym isn’t all that clean either, and yet we have to get some exercise to stay healthy, especially because lots of people have trouble with calorie consumption.

A British nutrition journal published a review of 53 scientific papers on a phenomenon known as “sugar-fat seesaw,” in which people trying to avoid sugar eat more fatty foods and people trying to avoid fat eat, well, more sugary foods — sweet cereals instead of bacon for breakfast and so on. Fortunately, the experts have found a solution: Don’t overdo in any direction. Don’t laugh, millions of us grow old before figuring that out, or in some cases, don’t grow old because we didn’t.

Our brains are magnificent instruments, but they do have some quirks. There’s a new study that finds the appearance of silverware can affect the way foods taste. Yogurt seemed denser and more expensive when eaten with a plastic spoon, cheese saltier when eaten from a knife rather than from a fork. Plates and glasses matter, too. Test subjects rated a drink more refreshing when they drank from a glass in a color they associated with cool than from a glass in a hot color, such as red. That’s not usually a problem, but the study reminds us how easily we can be swayed by little things we are unaware of.

Older people who are given a memory test after being reminded that memory weakens with age do worse than seniors who take the test without being exposed to that idea, according to a study from the University of Southern California.

We know this phenomenon as stereotype, and it has been shown to affect members of any group when they are exposed to reminders of a negative stereotype that is applied to their group.

How others see us affects the behavior of the stereotyped and the person doing the stereotyping.

An assessment of 10,000 newspaper articles on political races found that when a race included a woman candidate, the balance between coverage of character traits and coverage of issues changed. The focus on character traits was higher when a woman was among the candidates than when both or all candidates were men.

Another study involving politics looked at how states responded to low graduation rates. The study by researchers at Baylor University found that both citizens and legislators were more likely to be alarmed or to take action when white students were affected than when black students were failing to graduate. White-student failure signaled a need to improve teacher quality.

Awareness of a problem is a necessary step toward resolution. We can’t do better without knowing better, which is why we constantly probe ourselves and our behavior. It can take a long time for new information to sink in and erode old behaviors, but we are an adaptable species.

The good thing is that perceptions can change. Just look at how attitudes on marriage equality are evolving. Young people took the lead in moving society forward on that issue, which suggests our future is in good hands, washed clean of at least one old stereotype.

Jerry Large’s column appears Monday and Thursday. Reach him at 206-464-3346 or jlarge@seattletimes.com