Women with low heart rates have shown a propensity for crime
Low heart rate in women is associated with more frequent crimes and unintentional injuries. This is the conclusion reached by researchers from Sweden.
In studying the causes that lead to crime, researchers have mostly focused on social factors and personality traits. Less is known about the connection between law violations and biological characteristics, although there are a number of studies on this topic. According to them, for example, criminals often have damaged fragments of the prefrontal cortex, which is involved in decision-making, and childhood lead exposure can lead to illegal behavior in adulthood.
Researchers from the School of Behavioral, Social and Legal Sciences at Örebro University in Sweden found out which biological characteristics are more likely to lead women to commit crimes. They conducted a study involving 12,499 women born between 1958 and 1992 who were drafted into military service. The female participants were measured for heart rate and blood pressure at rest. In addition, the researchers examined records of their violent and nonviolent crimes and unintentional injuries up to age 40. The findings were published in the journal PLOS One.
Female recruits with a heart rate of less than 69 beats per minute had a 35% higher risk of criminal charges than those whose heart rate exceeded 83 beats per minute at rest. Scientists did not find a link between low heart rate and violent crime specifically. That is, those who had a lower pulse, although they committed crimes, but of moderate severity, without the use of violence. Women with low blood pressure (no more than 113 millimeters of mercury) were more likely to be convicted of violent crimes, and those with high blood pressure (at least 134 millimeters of mercury) were less likely to be convicted of non-violent crimes.
Participants with low heart rates were also prone to unintentional injuries. The authors of the publication explained this by a possible feeling of fearlessness and the need of the autonomic nervous system (it is responsible for unconscious processes in the body, such as breathing and heartbeat) in additional stimulation.
According to the scientists, the results should be treated with caution. First, the sample consisted of female enlistees, who may differ from women with other experiences (for example, women who enlisted are known to commit crimes less frequently overall than others). Second, other ways of measuring heart rate and blood pressure are likely to produce more accurate readings that would affect the conclusions of the study. Thirdly, the authors of the paper did not have information about the measurement conditions, such as room temperature and time of day. It is also important to keep in mind that not all factors that could influence the results were studied, and some of the injuries may not have been related to fearlessness and risk-taking, but to general reckless behavior.
Nevertheless, the study authors noted, the findings can be considered compelling and support the link between the autonomic nervous system and crime in women: "Our study reveals a compelling association between lower resting heart rate and increased risk of [nonviolent] crime and unintentional injury among female conscripts. This association, previously reported primarily in males, paves the way for innovative strategies for predicting female crime risk."
Recall that similar patterns have previously been found in men. Meanwhile, a lower resting heart rate is generally associated with a larger working heart volume and/or lower stress levels. It is still not quite clear how such features of a person can be associated with an increased likelihood of committing crimes.