“In the anatomy of violence, the heart is a central organ orchestrating the tendency to antisocial and violent behavior.”
Adrian Raine, The Anatomy of Violence: The Biological Roots of Crime


Let’s start with studies of aggressive behavior in animals.

In Physiology & Behavior 52, 33-36 is a paper titled Long-term heart rate responses to social stress in wild European rabbits: predominate effect of rank position. In Folia Primatologica 20, 265-73 we find Heart rate (radiotelemetric registration) in macaques and baboons according to dominate-submissive rank in group. The Journal of Autonomic Nervous System also gets in the act in Suppl., 657-70 with Vegetative and somatic compounds of tree shrews’ behavior. What are all these papers finding? As Adrian Raine, who collected all those references put it, “Rabbits who are aggressive and dominant indeed have lower resting heart rates than subordinate, non-aggressive rabbits.” Lower resting heart rate, it turns out, is the second strongest indicator of “someone becoming antisocial and violent.”

Adrian participated in a meta-analysis of forty publications dealing with the heart rate-antisocial relationship in child and adolescent samples. They involved a total of 5,868 children. The correlation that antisocial kids have lower heart rate was .22 or about five percent of the differences. This is a big deal in medical science where for comparison the correlation between smoking and lung cancer is .08 or taking aspirin to reduce the chance of heart attack is .02.


If you or I were brought into a police interrogation and accused of a serious crime and answered all their probing questions with lies, our hearts would race and we would sweat profusely. Yet this is just the response that is lacking in many of those we call hardened criminals. These physiological reactions are controlled by the autonomic nervous system which consists of both the sympathetic and parasympathetic systems. In a previous post we looked at these systems, in particular how little modern culture values the parasympathetic system which allows us to feel relaxed, secure and at ease with well-being. This tiny percentage of individuals we are considering here seem to be at ease, yet in circumstances in which such a response strikes us as alien.

Heart rate variability in connection with our breathing is controlled by the vagus nerve which has been found to also play a central role in how we relate to one another. It “links directly to nerves that tune our ears to human speech, coordinate eye contact and regulate emotional expressions.” It seems almost too simple to be true but “Studies have found that higher vagal tone is associated with greater closeness to others and more altruistic behavior.” The vagal tone is measured by higher variability in heart rates. Well-toned it lowers risk of heart disease. The nerve also seems to be related to glucose production, our immune system, and even to the production of oxytocin. Please read more in the Time’s ‘The Biology of Kindness: How it Makes Us Happier and Healthier.

Regardless of how insane specific actions in these violent crimes might be, we cannot deny that the perpetrators are driven by human needs not wholly foreign to ourselves. As much as we might want to cast such people into the role of wholly other, they are members of our species. They are not monsters from some supernatural plane – though it is quite possible their biology, and their experience of consciousness that arises from it, are very different than what you or I experience. (The poverty of our language and conceptual frameworks for discussing altered states of consciousness does not do us any favors here.)

One of those biological differences concerns the heart as mentioned. When we are confronted with the details of these crimes the perpetrators seem heartless to us, as if they lacked a basic element of empathy. Studies have shown that this intuitive response is not that far from the mark. It turns out that there are two predictive indicators that a person might grow up to become a psychopath. The first was mentioned last week; they come from childhoods spent institutionalized or in broken and abusive homes. The second is that they have a slower heart rate.

That there is this correlation with a slower heart rate has been known to researchers for quite a while. In spite of this data there is still no general agreement on why this particular detail is involved. Contemplatives who have spent time working with the heart center of the body as it is experienced in meditation will not be surprised. It is a difficult work, an illustration of which will close this week’s essay. First it might be profitable to review the scientific speculations on why a slower heart rate might be so strongly correlated to psychopathology.

One explanation points to a lack of fear in such individuals. Transfer our example of the police interrogation to a bomb disposal context, and the soldier with the steady hand controlled by a steady heart beat has just the fearlessness you need. Another explanation points out the importance of another finding, that children with lower heart rates are less empathetic. It is easier to punch a human face if you don’t really feel within yourself what it is like to be hit. Another school of thought suggests the low arousal state of lowered heart rate is very unpleasant so people react by seeking high arousal stimulation. One detail from this set of studies is particularly interesting in light of the previous comments about the effect of media violence on children. Lower heart rate kids tend to choose to watch more violent material, that which is showing more intense anger, than those with higher resting heart rates.

It stands to reason that the less self-satisfied we are, the less content and complete within ourselves, the more we will cling desperately to items and events in this world, needing them to be just the way we want them to be. Our happiness project is serious, important and vital – eee gad, our very existence is at stake. On the other hand, if we are fundamentally ok with our simple innate goodness and the innate goodness of the cosmic container in which we exist, all that is undone. There is no possibility of any particular set of causes and conditions ever really being an identity-threatening reality in any ultimate sense. Living this colorful life with a light touch is possible, if we are not slave to a sense that our very existence is at stake with every sling and arrow of outrageous fortune. We have never really had the type of existence we are afraid to lose, as if our very being was dependent on ourselves alone.

There are two thoughts that keep reoccurring to me when I contemplate the people that do the types of dark deeds we have been discussing these last few weeks. Each provides a bridge, however shaky, from self-righteous rage towards a more productive attitude that seeks to relieve suffering. The first is that their lives are not that unlike my own 99.9% of the time. The other is that they are cut from the same biological cloth as I am; they come from the same warp and woof of deep time processes unfolding in the here and now.

Have you ever done something you regret? When the lives of perpetrators of violent crimes are examined somewhere close to 99.9% of them are filled with actions not all that dissimilar to those that fill your days. They cooperate on roads while driving like everyone else and wait in lines just like the rest of us shoppers and all the rest of it. This is why so many neighbors comment that the killer was just a “nice boy next door.” It is just a few fateful moments that separate their paths so irreversibly from our own. That they might pay with years in prison for actions of a few moments should cause us all to take humble inventory of our capacities.

The psychological truth is that when we are able to face the darkness and sit with it, accepting that suffering is in fact painful, we simultaneously acknowledge the dignity of the people who are going through these ordeals. It matures our character to spend some time stewing in the facts of life. Sharing the pain of others for a moment, however little or much we might, we become more “real.” We moderns, isolated as we are from encounters with actual death and blood, have a tendency to make light of suffering, pretending it is the proper subject for spoof and entertainment. All that fake bravado is just so much whistling past the graveyard. We need all the courage we have to sit honestly with our own fear of being hurt in order to pray that the suffering of others might be lessened.

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