This episode is also on Bilibili too.
In this episode, I’m introducing a physiological indicator: resting heart rate. To some extent, this indicator can predict whether you might become a criminal.
I saw a question on Zhihu: “In criminology, what characteristics make someone more likely to commit a crime?” It’s a pretty sensitive question. What it’s really asking is: could criminals be born that way? Could some people, simply because they were born with physiological or psychological traits that differ from ordinary people, be more likely to commit crimes?
And it turns out this kind of factor really does exist. One particularly classic example is low resting heart rate. Resting heart rate is how fast your heart beats when you’re not exercising, in your everyday state. So a low resting heart rate means your heart beats especially slowly in daily life. Quite a bit of evidence has found that many violent offenders have this physiological feature. Cambridge criminologist David Farrington conducted a study analyzing dozens of physiological and psychological factors that might be related to violent behavior. In the end, the strongest predictor of violent behavior was low resting heart rate. Before this study, the strongest predictor scientists had found was “parental criminality”: if a parent had a record of violent crime, the child would be more likely to display violent behavior in the future. But low resting heart rate was an even stronger predictor than “parental criminality.”
So how low does your heart rate have to be to count as a low resting heart rate? I’ll give you some reference data below, and you can use it to make a rough assessment yourself.
Resting heart rate changes as we get older, and there are also differences between men and women. I found the most comprehensive set of statistics for everyone. They came from more than 40,000 samples collected and analyzed by the US DEPARTMENT OF HEALTH AND HUMAN SERVICES.
The chart you’re looking at now shows how men’s resting heart rate changes with age.
Age is on the horizontal axis, and pulse—the number of heartbeats per minute—is on the vertical axis. The solid line is the median pulse: half of people have a faster heartbeat than this line, and half have a slower one. The pulses of the 50% of people above and below the median fall within the dark-purple area on the chart. And 90% of people have a pulse within the light-purple area.
The last chart was for men; this one shows the resting-heart-rate data for women. Generally speaking, women’s hearts beat a little faster than men’s. That’s because women’s hearts are, on average, smaller, and pump a little less blood with each contraction, so they need a slightly faster heart rate to make up the difference in blood supply.
With these two charts, you can now measure your own resting heart rate and see roughly where you fall within the population.
To measure your resting heart rate, sit down and rest for 4 minutes. Then use a stopwatch to count your pulse for one minute. If you have a smart band or something similar, you can use that too, though they don’t seem especially accurate. Honestly, counting the beats at your wrist may be better.
Roughly speaking, if your heartbeat falls below the light-purple area—in other words, if your heart beats more slowly than 95% of people’s—you probably count as someone with a fairly low resting heart rate. If you’re a professional athlete, though, that’s a different story. Well-trained athletes generally have low resting heart rates.
My own resting heart rate is 65 beats per minute. I’m currently 41 years old, and I fall within the dark-purple area on the chart, so you could say I’m extremely mainstream. I’ve always thought I was pretty hardcore, maybe even a little bloodthirsty, but apparently I don’t have what it takes to become a violent criminal.
There is one point I should make especially clear: not every type of violent offender has a “low resting heart rate.” It’s only the “cold-blooded” kind of violent offender whose heart beats particularly slowly.
Broadly speaking, violent crime has two typical forms. One is the “hot-blooded” kind: someone gets worked up in the moment and commits an impulsive crime. These offenders typically have problems with executive control in the brain. Once they act on impulse, they can’t control themselves. Their crimes are unplanned and driven by emotion.
The other kind of violent crime is the exact opposite: the “cold-blooded” kind. The offender stays calm, carefully plans the details, deliberately selects victims, and carries out the crime with a cool head. Many serial killers belong to this cold-blooded category of violent offender. We often say serial killers are psychopaths, which makes it sound as if they simply can’t control their behavior. But in reality, what’s twisted about serial killers is their desire; their methods and plans for killing are extremely meticulous and extremely calm. The kind whose heart usually beats very slowly is this cold-blooded type of violent offender. Strictly speaking, though, my constitution doesn’t seem to have the potential to turn me into a cold-blooded psychopath killer.
The father of neurocriminology, Adrian Raine, conducted an analysis pooling data from more than 5,000 children. The results showed that the factor most closely associated with low resting heart rate was antisocial behavior in children. Put simply, antisocial behavior means treating other people as if they aren’t really people—deliberately hurting or abusing them, even robbing, arson, or murder. The cold-blooded violent offenders we just discussed often score very highly on measures of antisocial behavior. They are the most extreme antisocial individuals.
So low resting heart rate is clearly correlated with antisocial tendencies and with cold-blooded violent crime.
But why is that? Why are some people with low heart rates more likely to display antisocial behavior?
In Anatomy of Violence, Adrian Raine summarizes three theories.
Fearlessness theory
The first is “fearlessness theory.” People with low resting heart rates are less likely to become tense or anxious, and less likely to feel afraid. In one study, researchers put participants in highly stressful situations, such as meeting a stranger or solving math problems under time pressure. They found that people with low resting heart rates appeared more fearless in these situations. No matter how tense the atmosphere was, they stayed calm, while people with high resting heart rates looked quite panicked. Apparently, the Chinese phrase for “heart panic” really can be understood literally.
As I said earlier, antisocial, cold-blooded violent offenders need a calm, fearless state of mind to carry out their criminal plans. That fearless state of mind may be supported by a low resting heart rate.
That is fearlessness theory.
Empathy theory
The second is “empathy theory.” Experiments have found that children with low resting heart rates have poorer empathy than other children. A lack of empathy means it’s harder for them to put themselves in someone else’s shoes, and even harder to imagine what it feels like to be bullied or beaten. So these children may also be more likely to display antisocial behavior: “I don’t treat you like a person because I can’t feel that you’re a person.”
That is empathy theory.
Stimulation-seeking theory
The third is “stimulation-seeking theory.” This view holds that a low heart rate reflects an insufficient level of arousal. Staying in that state for a long time can feel very unpleasant, so people with low resting heart rates are more likely than average to seek stimulation. Only in highly stimulating activities does their arousal reach a level that feels pleasurable.
So from the perspective of stimulation-seeking theory, the reason a low-heart-rate psychopath killer plans a crime in such a “cold-blooded” way may be precisely to experience the “hot-blooded” rush of the moment when the crime is carried out.
That is stimulation-seeking theory.
So, people with low heart rates may be more likely to display antisocial behavior because they’re not afraid, or because they can’t empathize, or because they’re seeking stimulation. It may also be a combination of all three.
One final point: there are many factors that influence criminal behavior, and they are extremely complex. Low resting heart rate is merely statistically correlated with a person’s future violent behavior. It absolutely does not mean that a low resting heart rate inevitably leads to crime. Everyone should be very clear about that.
The psychological and physiological traits associated with criminal behavior are a huge topic. Adrian Raine’s Anatomy of Violence alone discusses the psychological and physiological characteristics of dozens of types of offenders. If we get the chance, I’ll share more of the interesting details from this book with you in the future.
All right, that’s all for “resting heart rate and violent crime.” I recently published a new book, 24 Frames of Psychological Codes: Psychology in Film. What secrets are hidden inside the minds of great directors like Wong Kar-wai, Ang Lee, Christopher Nolan, Hayao Miyazaki, and Chen Kaige? What psychological codes are hidden in classic movie plots? What psychological meanings lie behind the various setups in science-fiction, horror, and wuxia films? If you enjoy watching movies and pondering questions in psychology, this book may bring you some fresh and interesting perspectives. You can click the link below the screen to learn more about 24 Frames of Psychological Codes. Thanks for your understanding and support. If you enjoy my program, please follow, like, save, and comment. It really matters to me. I’m Zhichao Wei. See you in the next episode!
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