Most American police officers are just like everyone else, says psychologist Paul Ekman. One of the only real differences is that when an officer’s emotions get the best of him or her, the consequences of those actions tend to be much greater — and sometimes even deadly. Ekman, who is one of the world’s foremost experts on emotion, suggests that police departments would benefit from keeping risky officers off the streets, and that identifying these officers would be easy with the adoption of a simple daily diagnostic test.

Paul Ekman: Police are there to protect us. They’re there for our safety. Now occasionally, there will be a bad apple, but my work with police has suggested that that’s really exceptional. The problem is they have a gun, so they can do a lot of harm quickly. But that’s overwhelmingly not the problem. The problem is the pressure that police are under to make instant decisions for safety, for their safety and the safety of others.

We all have bad days. We all have days, or most of us, where we say, "I wish I hadn’t said that. I wish I hadn’t been so impatient. I was off today." Well if a policeman is in that state, and they’re not any different than the rest of us in that regard, it’s a lot more dangerous. So it’s a dangerous job that requires that you’re in a calm state of mind when you go out to perform it. And we have the means to both assess that and further that. We’re just not deploying it.

My biggest dream — and I haven’t yet been able to convince any police department to try this is to see whether we couldn’t have a really fast, easy technological assessment. So before someone goes out on the beat, they sit down and their heart rate, blood pressure, skin conductance is monitored for five or 10 seconds. It says, "Yes you’re in your normal state; go ahead and good luck." Or, "Boy, you’re very aroused today. Let’s see if we can do something to help you calm down a bit before you go out on the job." We have the means to do that. I believe it could reduce some of the problems we currently have because police are human like everyone else. All human beings have bad days. We need a way to be able to specify this policeman’s having a bad day today. Let’s see what we can do with a few minutes of a few exercises to bring him into a calmer state so he can go out and do his job in a way he won’t regret, or she won’t regret.