The Daily Mail blames “brain chemicals” for riots… the research they cite doesn’t

Daily Mail headline: Rioters have ‘lower levels’ of brain chemical that keeps impulsive behaviour under control

Do they? Well, some of them might, but the research in question wasn’t about rioters at all.

Researchers from the University of Cardiff uncovered a link between impulsiveness and levels of the neurotransmitter GABA in a key brain region.

… Around 30 male university students had their levels of GABA measured using a specialised type of brain scan.

They were also asked to complete questionnaires that assessed different aspects of impulsiveness, a trait known to influence self-control.

Participants with more GABA in the pre-frontal brain region had lower scores for ‘urgency’ – the tendency to behave rashly in response to distress or strong emotions and urges.

There was no connection to rioting in the study. Any connection made in the article is being made by journalists – this article has no by-line, being published solely under the Daily Mail Reporter name, but I think it came from the Press Association originally – and it’s a tenuous connection. You see, The Mail is working completely backwards here – they’ve decided that since people who have less GABA tend to behave more rashly, people who they think behaved rashly must have less GABA. You might as well assume that since every MP is in London right now, everyone in London is an MP.

Besides, although the paper in question, “Dorso-lateral prefrontal gamma-amino butyric acid in men predicts individual differences in rash impulsivity” (in Biological Psychiatry not Biological Society, despite what The Mail claims) did find a connection between GABA and impulsiveness, it wasn’t as strong as The Mail claims:

Figure 1 from the paper

Figure 1 from the paper (highlights my own)

That’s a graph from the paper, showing the connection between the amount of GABA in one particular part of the brain (along the bottom axis) and how strong the individual’s feeling of urgency was (along the side axis) in two groups (cohorts). There does appear to be a correlation (the R number is a measure of how strong this correlation is; R = -0.7 is a reasonable correlation) but look at the two I’ve highlighted with red dots in cohort 2. These two people have the same amount of GABA in their brains, but one of them was incredibly impulsive while the other was one of the calmest people in the study. Likewise, in cohort 1, while there was a definite tendency for people with more GABA to be less impulsive, just look at that cluster of dots – there are impulsive people with lots of GABA, and cautious people without it.

The best you could possibly say about this article is that maybe on average a rioter* has less GABA than normal, assuming these riots are entirely impulsive and there is nothing at all planned or premeditated about them. But then, why does this study need to be connected to riots at all? The paper came out in July before the riots, it’s not about riots – or any kind of violence at all – and none of the scientists quoted mention them, and to be honest, blaming the riots entirely on brain chemistry leaves a nasty taste in my mouth. As Mindhacks has pointed out, The Daily Mail seems to be going to great lengths to avoid exploring any of the context behind the riots, and this kind of story helps bolster the Mail‘s line that there is no deeper cause of these riots than “criminality pure and simple”.

Wales Online originally ran this story too (here’s the Google cache, and if that stops working, here’s a screenshot), but they’ve since realised there’s nothing in this proving anything about the brains of rioters and have replaced the story with an altogether more reasonable report on the research. Will The Mail follow suit? Let’s see.

* Male rioters at least – the study only looked at men, so there’s no guarantee this correlation is true in women too.

Edit: The researchers behind the study have published a scathing rebuttal in The Guardian, saying “Let us be absolutely clear. Our research has almost nothing to say about rioting, and certainly can’t be used to justify or excuse any type of behaviour.” Despite complaints from the scientists, The Mail‘s article is still online.

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  1. #1 by Marcus on Thursday, 11th August 2011 - 16:13 UTC

    I suspect that even if the rioting behaviour was entirely impulsive and contained no preplanned, premeditated element that the rioters brains exhibit the same normal range of GABA in this brain region as any other sample of the population. The connection found in the paper after all was between the brain chemical and answers on a questionnaire NOT actual impulsive behaviour (which can have other, socio-economic or immediate causes).

  2. #2 by Frederic Boy on Thursday, 25th August 2011 - 9:38 UTC

    Thanks for this clever and balanced article.

    Re. your remark on the “two points in figure 1”, I would like to say that it’s exactly why we scientists (from nuclear physics to behavioural sciences) use the very same statistics and cite p-values to assess them. Any dataset is said to be corrupted by random variations of various sources, what’s important is that these sources of variability are not too important (the role of our statistic is to assess them). As an illustration, in our case the fact that repeatedly, in two independent groups of subjects, we find a functional relation between a measure of impulsivity and the concentration of a neurotransmitter outweighs other sources of variation (for instance, it’s true that some individuals may have comparable GABA levels while scoring differently on the impulsivity scale). There are several ways of assessing the “quantity of random variations” in a correlation, in the paper we use inferential statistics (the p-value comes from a Student’s T-test) and a probabilist method called bootstrapping (look for the wikipedia pages on these topics).

    Frederic Boy

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