Are we designed for violence?

I thought I’d post a short essay, originally written for another destination, that touches on issues discussed below in a previous post. It’s also cross-posted at my own blog. Hope y’all enjoy, and I welcome any feedback or crit of my somewhat contentious take on the issue.

Violence is common to our present, history and prehistory. Is there reason to hope that our future will be different? Doubtless we’ll know in the long run, thanks to the grand uncontrolled experiment of life. Meanwhile some argue we can get an early forecast by using the behavioural sciences – investigate our nature to divine our future. But just what do we mean by a violent nature, and would such a nature necessarily force us to be so pessimistic? Such a wide issue needs to be viewed through a narrow prism, so here we shall focus on the neuroscience of violence. Are we wired for violence Рis it brain-based, an original sin never to be expelled? Or could it be less indelible than we fear?

While examples of human violence are varied and plentiful, the most chilling are those individuals who seem innately disposed towards causing suffering: the Hannibal Lecters of the world who seem calm and controlled as they torture, scheme and kill. Psychopathy is marked by a total lack of empathy with others, allowing them to act without compunction. The rare cases of acquired sociopathy, where brain damage leads to behavioural patterns that resemble the psychopath, are perhaps even more unsettling. It’s one thing when it’s the other guy – born different. But the acquired case holds the terrifying promise that it could be you.

While we shiver at the horridness of all this, scientists have leapt at the chance to study these individuals in the hope that it may shed some light on whether we have a design for violence. As with much research, the exception helps you find the rule: the differences in the psychopaths’ brains and behaviour give insights into what is shaping the behaviour of normal people. One thesis that has gained broad popular attention (to which popular science writer Steven Pinker devotes a chapter of his recent book The Blank Slate) is that cases of violence running wild illuminate the caged beast inside all of us. This account argues we have inclinations towards violence only barely kept in check by imposed restraints; not dissimilar to a popular religious notion that humanity is fallen from grace -urged to good but drawn to evil.

It seems true that abnormal populations differ from us because they lack some kind of restraint: some failure of an inhibition mechanism which ordinarily screens out or rejects violent actions in healthy individuals. James Blair, a leading researcher in this area, has termed this a Violence Inhibition Mechanism (VIM, see e.g. Blair & Cipolotti 2000): and follows early ethological work showing that some animals in the wild cease their aggression if their victim shows signs of distress (Lorenz, 1966). Evolutionary pressure could promote such a tendency to discourage fighting to the death, switching you off from pursuing a conflict once your opponent caves in.

Other researchers point more generally to the role that the frontal lobes of the brain play in inhibition of inappropriate behaviour, suggesting that problems with these regions lead to the failure to inhibit violent acts. The two explanations may not be exclusive, but the inhibition-frontal lobe thesis is primarily investigated in acquired cases, whilst the VIM is researched in developmental cases. The upshot is that proponents of a deep and negative human nature argue that as we are engaging in suppression, there must be something there to suppress – therefore, there is violence within us. For example, Steven Pinker (2002) states that ‚Äúdirect signs of design for aggression‚Äù include the fact that ‚Äúdisruptions of inhibitory systems…can lead to aggressive attacks‚Äù (p316).

But this conclusion is premature in principle, and not supported in practice. Firstly, the principle. The argument that we can judge our inclination to violence by observing it in a free situation is flawed because it doesn’t take base rates into account. By base rates, I mean what our level of violence would be if we were `violence blind': if we had no interest, but no disinterest, in whether our actions caused harm.Science fiction author Isaac Asimov recognised that this rate would not be zero, and made this a key concept in his Robot trilogy, the First Law of Robotics. This was the rule which trumped all others, and commanded that
“A robot may not injure a human being, or, through inaction, allow a human being to come to harm.”
The robots are not given this rule to counteract some kind of ‘assassination chip’ placed there by a mischievous designer, but simply to act as a guiding principle to distinguish certain kinds of actions into acceptable and unacceptable. Asimov saw that you would need an inhibition system in place even when there is no tendency to cause harm; without specifications, harm will tend to occur. Without establishing fully what such a base rate would be, it is absurd to look at the harm any individual causes and conclude this is evidence for violence worked into the design.

When we turn to the evidence, violence for its own purpose does give a good account of the actions of these patients. For example, Blair and Cipolotti (2000) describe a patient with frontal lobe damage whose use of violence was goal-directed, for the purpose of excitement (pushing another resisting patient around in a wheelchair at speed) or to protest when frustrated. This does not resemble the sating of a wild hunger for aggression, but is more like a slide towards the base-rate – uncaring that your desires have harmful consequences.

It is difficult to see how someone could seriously advance the perspective that we are innately violent – commit violence far in excess of the base rates. Even considering the bloodiness of human history (and leaving apart the social factors underpinning conquest and genocide), the potential bloodshed from the base rate is equally boggling. Moreover killing for the sake of it would be inefficient, and considering our basis as a social species would be utterly foolish, so it makes good evolutionary sense that we are not drawn to violence.

So let’s retreat a little: perhaps the issue isn‚Äôt innate violence, despite the rhetoric; perhaps the argument is that we’re not averse to using violence, that we use it when it pays, much like we would do if we used the base rate. This is an issue that evolutionary psychology often investigates, modeling factors to uncover in which situations it would pay us to commit harmful acts (such as to revenge a slight in a culture of honour (Cohen, Nisbett, Bowdle, & Schwarz. 1996). All very well, if proving very little about violence in the brain. But however productive this line of research is, even this weak version finds a fairly big stumbling block, in the very phenomena we began with: the existence of systems that work to inhibit violence.

We took aside these inhibition systems (i.e. looked at neurological patients with damage to the areas that they reside in) in order to say ‚Äúlet‚Äôs look at what‚Äôs really going on.‚Äù But whilst this approach can tell us useful things, we need to put it all back together again: what makes us human isn’t just what lies beneath our inhibition systems, but is the fact that we inhibit at all, in such a sophisticated and complex manner. This is what renders the quote from Pinker so empty: the inhibition system itself is a product of design.

Anyone doubting that treating other people as more than instruments is founded in the brain would do well to look into developments in the study of self‚Äìother mapping. This has provided stronger and stronger evidence that these relationships are hardwired into us, strikingly with the discovery of mirror neurons that fire in the same way for events that occur to you or to those you observe (Gallese and Goldman 1998). Many argue that empathy is an outcome of these representations (see e.g. Frith and Frith 1999). And recent research demonstrates appreciating someone else’s pain activates many of the same areas as experiencing it (Jackson, Meltzoff, & Decety 2004): good evidence for a VIM-like mechanism, and certainly a rebuttal to those who think our withdrawal from violence is unnatural.

By making psychopaths into poster-boys for innate violence, we risk ignoring crucial aspects of their behaviour. The patients investigated by Blair and Cipolotti were reported as socially inappropriate in a variety of ways, and recent imaging work suggests that the areas crucial for regulating and preventing aggression also keep us within the bounds of socially acceptable behaviour (Berthoz, Armony, Blair, & Dolan, 2002). Rehabilitation would require addressing that big picture.

Designed for violence? Really, the strongest conclusion that this work can give is that we sometimes are violent when it’s in our interests. We are not innately disposed to violence, or even indifferent to violence, we are neurologically bound away from violence. This understanding gives us a solid basis for treatment, and an honest beginning from which to address the continuing problem of violence in society.

References

Berthoz, S., Armony, J.L., Blair, R.J.R., & Dolan, R.J. (2002). An fMRI study of intentional and unintentional (embarrassing) violations of social norms. 125, 1696-1708
Blair, R.J.R. & Cipolotti, L. (2000). Impaired social response reversal: A case of ‘acquired sociopathy’. Brain, 123, 1122-1141
Cohen, D., Nisbett, R.E., Bowdle, B.F., & Schwarz, N. (1996). Insult, aggression, and the Southern culture of honor: an “experimental ethnography.” Journal of Personality and Social Psychology, 70, 945 60
Frith, Chris D., & Frith, Uta Interacting Minds–A Biological Basis Science 1999 286: 1692-1695
Gallese, V., & Goldman, A. Mirror neurons and the stimulation theory of mind-reading. Trends Cogn. Sci. 2: 493-501, 1998.
Jackson, P.L., Meltzoff A., & Decety, J. (2004). How do we perceive the pain of others? A window into the neural processes involved in empathy. NeuroImage, 24, 771-779.
Lorenz, K. (1966). On aggression. New York, NY: Harcourt Brace and World.
Pinker, S (2002). The Blank Slate: The Modern Denial of Human Nature, Viking Press.

4 Comments

  1. Juzam29
    Posted May 31, 2005 at 6:49 am | Permalink

    Killing for the sake of killing might not be an adaptive behaviour. But killing for access to something would be. If human behaviour is selected by consequences as Skinner suggests. Why can we rule out that aggressive behaviour is not inherited? Putting aside all the ideas about where the behaviour is coming from, ultimately at any given time there are always choices about what we do.

  2. Posted May 31, 2005 at 10:56 am | Permalink

    I should make it clear that I’m not proposing to rule anything out. The post above assesses the current evidence and makes a judgment from that. To make a case for violence being coded as programs of behaviour as a result of adaptative forces one needs to demonstrate evidence of such programs, not merely the ubiquity of violence. It is this treatment of the issue, made by Pinker in his most recent book, that I am taking issue with; it just doesn’t make the grade.
    In my opinion, Pinker and other evolutionary psych advocates are very strong at gesturing to the adaptative forces that inevitably, inexorably, just must have been the cause of behaviour we see today (perhaps because it gives them a chance to take a break from proper science and read lots of Hobbes on the ‘war of all against all’). The danger is when they stop before the real heavy lifting, that of showing how the patterns of behaviour seen in the real world are better characterised as adaptive than learned behaviour.
    This is very tricky to do (even the classics in the field like the Cosmides and Tooby use of the selection task to show our preference for social contracts have come under heavy fire); many researchers rely instead on the axiom ‘if we can demonstrate selection pressure on a behaviour, then it must be an adaptation’, which demonstrates an overzealous and unscientific faith in the freedom and power that evolution actually has. This leaves their arguments to rest on some notion of plausibility, rather than evidence.
    If these popular treatments made stronger arguments, I would address these. As it is, this is in no way my area, so I don’t have the time or aptitude to generate a stronger one; I’m happy just to knock down this one by giving it a knock and listening for the echoes in its hollow spaces.
    As to choices, granted. This kind of research should not lead us into the explain/excuse fallacy, which is something that The Blank Slate does cover very well.

  3. Juzam29
    Posted June 3, 2005 at 1:44 am | Permalink

    It has been a while since I read the Blank Slate but I think what I took away from it is the concept of the so called Blank Slate is a myth. I do not see this book as been written for scientists, none the less some issues raised are quite important to those in the field of psychology. Like all people we are susceptible to commonly held ideas, but we have a particular obligation to try and find answers that are not bound by myths and false beliefs. I agree with you in order to really know if humans are programmed for violence that it would have to be supported with proof. How this process could be achieved I suspect would never get approval from any ethics committee. With what we do understand about behaviour and evolution I think out best guess would be people are wired for both good and bad which kinds of behaviours are most successful for the modern world would depend on where you live, as it would have always been. To be able to learn language we require the ability to do so as is likely the case for behaviours that go along with violence. To be able to get angry, feel jealousy, get enraged, display unique protective behaviours towards ones family we must have some capacity to process these feelings, the stimulus that act to elicit these cannot be only learned.

  4. Posted June 3, 2005 at 10:24 am | Permalink

    I’m glad that’s what you took away from the Blank Slate. I worry that there are two polemic aims of the Blank Slate, one laudable and one rather more shady. The first is to take away the Blank Slate, and moreover show that we need not fear its loss. That part is argued with lucid reasoning and a good degree of objectivity. The second is to say ‘in this post-Blank-Slate world, what political objectives should we be working towards?’ – the so-called “Hot Button” sections.
    This second section rides on the neutral, reasonable nature of the first, making it seem more objective than it actually is In his preamble, Pinker admits that this section is more charged: opinion as well as assessment. But this quickly becomes obscured, and the movers and shakers who will take these messages and say e.g. ‘science proves we must use punitive sentencing’ need to be corrected, by pointing out where is the science, where is the opinion, and where is the scientism.
    I think it is possible to conduct research looking at underlying programs of violence etc – and I’m sure many if not most of them are being pursued. These include: looking at the developmental time-course of violent behaviour – is it absent at certain ages and present in others, does it seem too sophisticated to be learned, do children act as if to intentionally cause pain before they are understood to mentally represent the feelings of others; a serious investigation into the epidimiology of violence with a consideration of base-rates – so making pronouncements about how humans have always had a bloody history doesn’t cut it. In my opinion the strongest evidence for a hard-wired program would be evidence that neurological damage selectively impairs violent behaviour – this is the classic way to show evidence for a specific brain/mind module, by demonstrating selective impairment. The cases described in the post and Blank Slate of psychopathy are in effect the opposite of this, showing evidence for a ‘pacifist’ module if they show anything at all; it may seem counterintuitive but if you want to pick extreme cases to demonstrate designed violence you should look at the non-violent and figure it out from there. (This wouldn’t require zero violent behaviour, but if found a class of actions that ordinary people are capable of doing was denied to that patient you could conclude that those actions are tightly controlled by that brain area, and suggestive of violent design.
    My biggest problem is I think people are trying to hang a label – ‘violent nature’ or what have you – when it is not apparent what we really mean by that.


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