Do your genes make you a criminal?

Chris Smith put J.J. Vigganio's question to Kyle Treiber from the University of Cambridge....

Kyle - There are thousands of factors that we know are associated with crime involvement and some of those are individual, some of those are biological, others are psychological but we also have mainly social aspects, environmental factors that we know predict crime. And I think once we are understanding more and more not only how many factors, but how interactive those factors are, we talk about multi-factorial effects, so, for example, it’s not going to be one gene. We have found very little evidence of any single gene having a huge influence on criminal behaviour. In fact, there seem to be many, many genes involved in any kind of outcome, physical or behavioural and, of course, behaviour is a whole other dimensions. Similarly, there are also very many environmental effects that are interacting with those genetic effects. So, ultimately, what we have are very small influences across many factors. So I think, actually, rather than saying is there any room left for free will, I think it’s quite clear that there’s plenty of room for free will because not any of those factors is going to be so influential that we have no options or choices but to do what it’s influencing us to do.

Chris - There’s a study from the U.S. last year which I remember reporting on. I was quite stuck by it, but they were showing it’s correlation not causation. You’ve got to be very careful how one interprets this but there was a lady showing that where you grow up, in terms of your exposure to pollution, strongly influences your likelihood of getting in trouble and having behavioural problems or even being dyslexic. And so, they were showing this strong correlation between maternal exposure to pollution and then these different behaviours in the children. So I guess that would be a good example here, wouldn’t it, in that the environment in which you grow up? The same individuals they controlled the study quite carefully, they compared individuals who lived in polluted and non-polluted parts of cities, there was this really quite profound effect.

Kyle - We see a lot of research that is like this, and it’s very interesting because it does suggest that something is happening. But a lot of what may be happening may not be a causal effect in the sense that the pollution is causing that, so the pollution may be having some effects on development which we could study and look at. But, arguably, there’s also going to be selection effects about the kinds of people that live in these neighborhoods. And those individuals, that selection of those kinds of individuals into this environments may be having more of an influence on the outcomes of the children than actually the pollution itself.

Chris - And the questioner mentions the fact that it very often is men. Why are we more prone as men to do naughty things compared to women, or are we?

Kyle - Well, one thing to think about is that it’s not being male that makes you more prone. So there are very many men who do not commit crime, far more than actually do and have any kind of criminal conviction. Being a male does not make it more likely that you will offend. There are certain things about males that may mean that you are more likely to be in situations that you would be vulnerable to offending.

Chris - More likely to get caught? Kyle - You could be more likely to be caught. There could very much be a selection effect that the police are more likely to arrest you or you’re more likely to get convicted for your crime. Chris - Women are better planners?

Kyle - Well, I mean we could argue that all day but as far as crime involvement goes I think there are a lot of differences. What we look at, for example, differences in what women think are right and wrong behaviors to do, their levels of self control. But also, in particular, their exposure to different kinds of environments, how much time the spend unsupervised with peers, handing out at night, drinking alcohol in city parks and so forth.

Chris - Interesting. James…

James - I was just going to come back to your point Chris about pollution and how it can really affect not only potentially your risk of future crime, but also there’s a very strong link with heart disease as well. And, in fact, it’s an inverse square law: the further you move away from the road the less your chance of heart disease.

Chris - And do we know why? James - It’s thought to be the nanoparticulate, the very small bits of pollution that can get straight into the bloodstream through the lungs and they can increase stress on the heart. Chris - How? James - Atherosclerosis, so hardening of the arteries; it exists in most people. But people with high levels of these pollutants in their blood, there’s more inflammation and this can lead to plaque rupture and heart attack.