Saturday 6 July 2013

A Biological Perspective on Intimate Partner Violence

From the perspective of practically every psychological scientist, human thoughts, experiences, and behaviours derive from the human nervous system. The structure of the human nervous system, itself, depends on the genetics that each person acquires from their parents and the experiences they have. Our brains consist of millions of neurons and the moment-to-moment electrical activity of those neurons is roughly equivalent to everything we are and controls everything that we think and do. In that way, all of psychology adopts a biological perspective, but a researchers’ emphasis might be at a level that is either very close or somewhat at a distance from the actual biological processes that determine who we are and what we do. Biological psychologists stay closely oriented to the genetic and neurological processes that underlie human experience and behaviour, so we may as well begin there with our series of discussions on IPV. It is also a convenient place to start, since our PSYC 1200 course begins with an overview of the human nervous system, after some introductory discussion about what psychology is, psychology’s history, and the sorts of research methods that psychologists rely upon.

A common approach to violence, whether intimate partner violence or otherwise, is to conceive of a tendency to engage in violent behaviour as reflecting a neurological defect. For instance, many psychological problems, such as depression and anxiety, can be understood as emerging from imbalances in the chemical composition of the brain. A neuron may stimulate the firing of another neuron (or it may inhibit the firing of another neuron) by releasing chemicals, called neurotransmitters, into the gap between the axon of one neuron and the dendrite of another. That way, the availability of one or more neurotransmitters determines how the brain functions. Too little or too much of a certain neurotransmitter in a person’s brain may disrupt that person’s mental processes and their behaviour. Consuming drugs, like cocaine, marijuana or Prozac, influence experience and behaviour by changing the amount of neurotransmitters that are available to stimulate neural impulses in a person’s brain. Perhaps IPV could be explained by structural defects or chemical imbalances in a person’s brain? Unfortunately, this approach has led to some overly aggressive treatments to control the behaviour of people who are prone to violent outbursts. Several decades ago, efforts to “cure” people with violent tendencies included electroconvulsive shock therapy (sessions in which a person has an electric current passed through their brain, Eller, 2006).

The rather simplistic (and incorrect) theory that motivated electroconvulsive shock therapy was that problems with the functioning of the brain could be fixed by the ordered electrical impulses provided by a community’s electrical power grid. Another approach was to sever certain parts of the brain from other parts or cut out other parts of the brain entirely. For example, a common treatment for those prone to violence and other erratic behaviour was to sever the frontal lobes of the brain from the rest of the brain. This procedure was called a “frontal lobotomy”. The procedure succeeded in eliminating violent behaviours, but mainly because it reduced a person’s tendency to engage in any behaviour at all (Eller, 2006).

The early days of psychology are filled with very stupid ideas and the reckless application of unverified theories, which often caused much more severe problems for people than they fixed. Unfortunately, in the name of psychology, there are people who still apply idiotic theories that have no scientific merit, causing a great deal of harm to people in the process. One of the biggest problems humans face, including some scientists who are meant to know better, is that we can develop strong beliefs in the absence of any scientific evidence and then act as though those beliefs are absolutely true. Acting as though false things are true, even when a person has the best of intentions, can be an extraordinary waste of time, money, and human lives. As just one example, quite a few depressed stay-at-home mothers and even some highly energetic children were given frontal lobotomies as a supposed cure, but the main outcome for them was permanently disabling brain damage.

There are people who do appear to have such dysfunctional brains that it makes them violent and neurological defects may explain some of the instances of IPV that occur. At the moment, treatment for people who are prone to violent outbursts involves prescription of medications, such as antipsychotics, that block receptors in the brain that receive the neurotransmitter, Dopamine. To make a long story short, dopamine pathways in the brain play an important role in mental stimulation and aggressive behaviours, such as violent actions. However, antipsychotics are mainly used to treat people with a severe mental disorder, such as schizophrenia, for which violent actions are quite indiscriminate. Intimate partner violence, most often, is not indiscriminate. The violence is focused on one individual, and it’s quite personal. People who engage in IPV are frequently not violent toward people, in general. Their violence tends to be aimed primarily at the people closest to them, which will naturally include their intimate partner. Although all of human psychology originates from the activity of the brain, in most cases it is not sensible to seek a neurological defect for the cause of IPV. Instead, it is more likely that IPV emerges from neurological processes that are, sadly, quite normal in humans. From that point of view, the evolution of humans as a species may have incorporated a natural tendency toward IPV, supposing that there exists a certain combination of environmental conditions. Those who are most likely to adopt that kind of perspective call themselves Evolutionary Psychologists, which is actually a sub-category of biological psychologists, who emphasize the role of inherited, genetic influences on human psychology (Eller, 2006).

Evolutionary psychologists may address the question of IPV by pointing out that violence is a prominent component of the behaviour of many species, and humans are just another species that has a tendency to engage in violence. The prevalence of violence throughout nature suggests that the tendency to be violent is something that we have inherited from our ancestors because it must have served them some useful purpose. Many thousands of years ago, the capacity to engage in violence must have made our ancestors more successful at surviving and reproducing, thereby allowing them to ensure that their genes would get transmitted inside of all of us, all the way into 2012. Hunting is a form of violence and that capacity has had obvious benefits for us and our ancestors, not to mention all of the other species that rely on hunting. Being able to fight when threatened is a form of violence and one that is quite useful for members of a species who would prefer to survive an encounter with a predator or an assailant. When a person wants something that some other person has, there is always the option of taking it by force, which is clearly something that would have provided our ancestors with a competitive advantage. Murder has been observed in many nonhuman species from insects to birds to nonhuman primates, like macaques (Eller, 2006). A capacity for violence should probably be thought of as something that exists within each of us as biological organisms, rather than as something that could only emerge from a diseased mind. All of us can quite naturally be violent and simply await the conditions that stimulate that kind of reaction from us. But, why is violence against intimate partners such a common form of violence in humans and why are men so much more likely engage in that kind of violence?

In response to those questions, someone could argue that a tendency to be aggressive depends on the amount of testosterone in a person’s system and, in humans, men have higher levels of testosterone than females. The problem with that response is that it doesn’t explain WHY men almost always tend to have more testosterone than women. The source of that difference in hormone level is ultimately genetic, which means that human males evolved to have more testosterone than human women for some reason having to do with it being more important for males’ success at reproducing than it is for females’ success at reproducing. The driving force behind human biological traits and those of all other species on the planet is “reproductive fitness”. The more offspring that a member of a species can produce that are in good enough shape to survive and reproduce on their own, the more likely it is that the genes possessed by that member will be represented in future generations of the species.

 (To anticipate that certain folks will have a pre-existing, strong dislike for the “Evolution by Natural Selection” approach to biology, the reader might expect us to say something as a hedge, like, “from the evolutionary perspective, reproductive fitness is what matters”. We won’t be doing that because our course is about a science and the science of psychology presumes that humans and all other species on Earth appeared on the scene gradually over the course of millions of years, with the traits of species determined by their capacity to allow members of the species to reproduce more than other members of the same species. These are the guiding principles that nearly all scientists have used for many decades to understand the biological species that exist on Earth. To entertain any alternatives would be intellectually dishonest of us and would be nothing more than cheap pandering. Traits inherited genetically through the process of evolution may only get us so far in understanding humans. There's also experiences and a person's environment to consider. However, there is, by now, no doubt in the minds of scientists that understanding humans requires understanding the evolutionary processes that gave us the DNA that we all have in common.)

An evolutionary psychologist would explain gender differences in violent behaviour with reference to how the capacity to be violent provides greater reproductive benefits for male than for female humans. The idea is that the reproductive success of females is more or less the same, whether or not they engage in violent behaviour. Female humans can only have so many children, anyway, since it demands so much time and energy for women to develop children inside of them and then take care of them after they are born. In the environment we all evolved from, if a woman was physically capable of reproducing, securing enough mating partners to achieve success at reproduction is very easy. By contrast, for male humans, there is virtually no limit to the number of children they could (theoretically) father. The only required cost of producing a child, from a males’ perspective, is one tiny sperm and contributing that doesn’t really take very long. For a woman, the required cost of producing a child is an egg, sustaining the developing baby for many months, facing the health risks associated with giving birth to a child, nursing, ensuring her infant’s and her own survival needs during those very vulnerable years as the child grows and slowly becomes able to be more independent, and so on.

In the primitive world we evolved in, although the sky was the limit for males, as far as reproduction went, the downside was that it was quite possible for only a few males to monopolize all of the females, leaving the rest of the males with no mating and reproduction opportunities. This situation is common in primate species, such as gorillas, in which one alpha male can dominate all of the other males and serve as the primary mate for all of the females in the group. An alpha gorilla doesn’t get to mate with all of the female gorillas by being polite. He earns that right by being the strongest and most viciously frightening gorilla. Violence maintains his high status and this kind of desperate competition for women to mate with was also the context in which human males evolved. Among humans, males tend to be more violent than females because being violent provided men with a major reproductive advantage over other men. It is understandable why men are so much more likely to fight and kill one another than women are. Historically, about two-thirds of all murders in the United States are committed by men against other men (Bureau of Justice Statistics, 2012). Even now, competition is fierce and, from the evolutionary psychology perspective, the ultimate goal for men, generally speaking, is to defeat other men for access to female mates. Evolutionarily speaking, women represent the reproductive resources that males need to transmit their genes. Once a man has attracted a woman to mate with, control over that resource is a priority and violence is one tool that a man may use to maintain that control.

There is an unease that naturally emerges when describing this evolutionary approach to understanding IPV. If such a proneness to violence embedded within the male DNA, what can we do about it? Fortunately, humans are much too sophisticated to be ruled completely by these inherited traits. Our evolutionary past means that men face a challenge that women do not face to the same degree and they must deliberately work to overcome it. Failure to overcome it risks their causing physical harm or even death to the people closest to them. The challenge for men is to overcome the tendency that evolution has instilled in them to treat women as property and to conceive of a woman’s role as to serve merely as receptacles for reproduction. A person’s experiences and social context can either facilitate the worst and most destructive parts of us humans that we have inherited from our ancestors or it can cause those traits to remain dark, primitive parts of us that we never express. A place like Canada has many mechanisms that tend to discourage IPV, relative to what humans would be likely to experience in the ancient world in which we evolved. We have a list of official crimes and punishments for those crimes that make it risky for people to violently attack their intimate partners. There are less formal risks involved, as well. We are a society that generally (or should we say “kind of”) abhors violence and many of us would shun a person for engaging in IPV.

In part, these restraints emerge from historically quite novel cultural values that favour gender equality over the more traditional view of women as property and as inherently inferior. (As one of hundreds of historical examples we may have chosen, the North Carolina Supreme Court dismissed a complaint against a certain Mr. Black for assaulting his wife in 1964 even though they were separated at the time, on grounds that “a husband is responsible for the acts of the wife, and he is required to govern his household, and for that purpose the law permits him to use towards his wife such a degree of force as necessary…” (Klein, 2004). Note that the amount of force deemed necessary tended to be left entirely up to the husband, making every male head of household his own sort of totalitarian dictator. We should be grateful to some of our most recent ancestors for dismissing these ideas and pulling us all out of the mud. The problem is that the genes remain and they support a persistence of gender discrimination and a persistent willingness by a fair number of men (not the majority, but a sizeable minority) to use violence to control “their woman”. To be fair, there is some much smaller group of women who have the same notions about “their men”. An interest in having power over others, and a willingness to use violence to maintain that power, is not exclusive to men.

Neither biological nor evolutionary psychology can provide much guidance in addressing this social problem, because they merely explain why humans are capable of violence and why some men (and even some women) will be violent toward their intimate partners. It is clear that most people can be encouraged to suppress whatever violent urges they might experience. Luckily, most people don’t assault their intimate partners, despite what their genes might encourage. That’s encouraging and suggests that a person’s experiences can be constructed in a way that will make them very unlikely to act violently toward their loved ones. Perhaps there are experiences that a person can have that would override the tendency to think about the world in a way that encourages violent action toward an intimate partner, such as viewing an intimate partner as property to be controlled by any means necessary? How experiences determine an individual’s behaviour is the primary emphasis of the Behaviorist approach to psychology, whereas the investigation of mental processes and how they guide human behaviour is the main focus of the Cognitive Psychology perspective. Those two approaches will provide the basis for our next two posts on IPV.  


References:

Klein, A. R. (2004). The criminal justice response to domestic violence. Belmont, CA: Wadsworth/Thomson.

Eller, J. D. (2006). Violence and culture: a cross-cultural and interdisciplinary approach. Southbank, Victoria, Australia: Thomson/Wadsworth.

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