jump to navigation

What do you know, additives really do cause hyperactivity September 29, 2007

Posted by Johan in Abnormal Psychology, Developmental Psychology, Psychopharmacology.
add a comment

This post is about a very different E211.

A few months back, the menu from of a local Chinese takeaway caught my eye. Apart from the lengthy questionnaire, which customers could complete to receive £2 off (pretty smart way of gathering customer data for a non-chain takeaway), the menu also made numerous claims that all products were absolutely free of additives, including the ubiquitous Monosodium glutamate (MSG) and colourings. This is a good thing, the menu claimed, because additives cause ADHD in children.

My initial reaction was to silently promise myself never to order from that take-away, just as I wouldn’t buy my aspirin in a pharmacy that sells magnet bracelets (although this is a hard rule to follow in the UK, where homeopaths are funded by the NHS), or books from the Christian Science Reading Room. However, it turns out these guys weren’t far off the mark, as a recent study from The Lancet shows (by the way and for the record, this is apparently by no means the first study to report this).

McCann et al (2007) recruited two groups of kids (ages 4 and 8-9), who received two additive cocktails and placebo in different sequences, all disguised in juice. While the exact makeup of the mixes varied, both featured Sodium benzoate (aka, e211). For reference, the contents of one of these mixes was about equivalent to the food colouring present in 2 56-gram packets of sweet for the 3-year-olds, so the doses were not far outside of what a kid might consume on a daily basis.

Using a range of behavioural and peer-rating measures, McCan et al were able to show that on the whole, one of the mixes was associated with increased hyperactive behaviour in the three-year-olds, while both mixes were associated with increase hyperactive behaviour in the 8-9-year-olds. So keeping your kids away from food colouring may not be such a bad idea, after all.

I think this is a beautiful finding, because it’s just the sort of result that I would dismiss as spurious, had it been obtained by an association study, e.g., “hyperactive kids consume more additives than non-hyper kids” (a topic I touched upon recently). It is quite easy to suppose that, for instance, hyperactive kids like sweet, sugary foods with lots of additives better than others, but apparently that isn’t the whole story. This is a prime example of the power of the randomised, double-blind control trial in ruling out alternative accounts.

So either the Chinese takeaway is lucky enough that a belief they held for the wrong reason happens to be true, or someone on staff reads medical journals. I know where to get my Sichuan chicken next time, anyhow.

McCann, D., Barrett, A., Cooper, A., Crumpler, D., Dalen L., Grimshaw, K.,Kitchin E., Lok, K., Porteous, L., Prince E., Sonuga-Barke E., Warner, J.O., and Stevenson, J. (In Press – don’t you hate how medics always squeeze in half the department as authors? It’s almost as bad as the human genome project publications. Anyhow, back to the reference). Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: a randomised, double-blinded, placebo-controlled trial. The Lancet.

Is is rational to Do No Harm? September 23, 2007

Posted by Johan in Abnormal Psychology, Behavioural Genetics, Emotion, Social Neuroscience.
1 comment so far

From the left: Josef Mengele, Rudolf Hoess, Josef Kramer, and unknown.

The picture above comes from a set recently added to the US Holocaust museum. The pictures have caused a stir since they depict staff at the Auschwitz concentration camp on what might in modern terms be described as corporate kick-offs and the like. I’m not sure why it’s surprising that the prison guards liked to relax and have fun now and then – clearly, they would not have taken up the position if they were not at least acceptant of the task at hand. There is little evidence that the third reich forced or ordered anyone to commit these atrocities, after all.

Mengele is an interesting character. As a leading physician in the camp, he (along with the other physicians) decided who would be sent to work and who would be sent to the gas chambers, as the captives disembarked their trains. He is also infamous for his cruel experiments on inmates. In particular, he collected twins, which were separated from the other inmates, and used to study the heredity of racial traits under much the same principles employed by modern-day twin studies in behavioural genetics, but without ethics committees or indeed basic human decency.

I came across an old NY Times article on Mengele, written by what I assume must be a psychoanalyst. Yes, the usual speculative attempts to explain the man’s behaviour as a function of repressed anxiety appear, but for the most part the article sticks to the story, re-telling the life and work of Mengele through witnesses.

Although this is probably not news to historians, I am struck by the contradictions and inexactness of the accounts, even though this is very recent history. Within the NY Times article, witness accounts frequently contradict eachother: Mengele is described as being an aloof person with no emotions, next he is playful, friendly (even in his role in deciding life and death on the ramp), and entertains his young twin subjects. When comparing the NY Times article to the Wikipedia entry or his entry at the Holocaust History Project, further discrepancies arise.

Yet, a clear picture emerges, and it is one of supreme rationalism and dedication to science (albeit science that turned out to be fundamentally flawed). These are terms that are usually considered positive in our society, so you may be excused if you think me a Nazi apologist for saying so. It’s quite the contrary, however. I think Mengele’s case highlights how the idealised image of the objective Academic, struggling only to further knowledge, can be a road straight to hell.

From a rationalist standpoint, it is relatively easy to understand Mengele’s decisions. As an anthropologist with an interest in heredity, he must have recognised that Auschwitz offered an unprecedented opportunity for all kinds of forbidden experiments. The NY Times article implies that this research opportunity may have been the very reason why he actively sought a position at the camp. From a moral standpoint, the prisoners at Auschwitz were going to suffer terrible suffering or immediate death regardless – one could then argue that Mengele only tries to make the best of the situation by adding to human knowledge, while killing and maiming. For Mengele, the suffering of the prisoners was likely a non-issue in any case, since the man was a rabid anti-semite, and considered his subjects less than human. In this sense, the work may have presented no more of a dilemma to Mengele than the dilemma a contemporary researcher faces in killing a macaque monkey after the conclusion of a single-cell recording study, in order to verify that the electrodes were placed in the right cortical location.

My point here is not to defend Mengele – he was clearly an appalling person who, apart from all other damage done, sullied the name of science. Still today, Mengele is the original template for the evil scientist, who seeks knowledge at any (human) cost. But it is unsatisfying to merely state that Mengele was “evil”, and thus did what he did. The NY Times article finally lets loose the full-on psychoanalysis towards the end, and this explanation proves no more satisfying:

His impulse toward omnipotence and total control of the world around him were means of fending off anxiety and doubt, fears of falling apart – ultimately, fear of death. That fear also activated his sadism and extreme psychic numbing.

I would prefer to invoke the behaviour of patients with damage to the ventromedial prefrontal cortex (VMPFC -the bit of brain just above and between the eyes). These patients display, among other symptoms, what can best be described as a lack of conscience. They are well aware of the conventions of society, but as the post linked above describes, their reasoning is defective. The defects do not appear in the expected, irrational direction, but rather in a rationality that is so extreme that is leads to horrendous decisions. These patients do advocate killing a crying baby in order to avoid the group’s capture and certain death at the hands of enemies. This is the most rational, utilitarian path to take – better the death of one than the death of all.

So did Mengele have an undetected lesion to the VMPFC? I don’t think so, and there is absolutely no way of finding out. Such an account would be as speculative as the psychoanalytic drivel cited above. I only wish to raise the possibility that sometimes, a behaviour as complex as immorality or a lack of conscience may arise from relatively simple lesions. Repressed traumas and anxiety may well cause such cruel behaviour too (who knows?), but a blow to the head strikes me as the more parsimonious explanation, if we’re going to speculate about it anyway

I don’t think Mengele was mad, evil, or suffered from repressed anxiety. He was a dedicated and supremely rational scientist. This is why he caused so much harm.

Faces everywhere September 21, 2007

Posted by Johan in Face Perception, Links.
add a comment


It’s amazing how faces seem to appear everywhere – whether this is a result of a face-specific innate mechanism, or just tons of practice with this particular class of stimulus. I recently discovered the wonderful Faces in Places blog, which is filled with examples of faces appearing in the most unlikely places. The picture above is perhaps a poor example of the human readiness to perceive anything as a face, since this particular item was likely designed with faces in mind.





That is a less plausible explanation for why these motorcycle gas tanks look like faces – they weren’t designed to be viewed from this angle.

We seem to be inclined to interpret almost any object with three enclosed dots as a face. This is quite different from other objects with which we have a lot of experience: you probably spend considerable amounts of time looking at your hands in order to guide your actions, but if you’re anything like me you  don’t see hands everywhere.

How useful is a group-level truth to the individual? September 18, 2007

Posted by Johan in Applied, Economics, Math & Stats, Social Neuroscience.
add a comment

Today’s post is about the tension between the often-times weak predictions of psychology and other sciences, and the decisions of the individual. My blog stats might serve as an example. The figure below plots the number of visitors over the last 30 days.

You would be hard pressed to make any predictions regarding how many visitors the blog will have tomorrow. Nor would you be able to say what the overall trend in the data is. The story is similar when we look at the number of visitors per week:

You can now predict that the blog should receive somewhere between 400 and 700 visitors this coming week, but it looks like the blog is receiving pretty much a constant stream of visitors. This is unlikely, considering how little blogging has taken place lately. Let’s look at the number of visitors by month instead.

At this level, the trend is very clear. The blog was growing steadily up until June, which is almost exactly when I went on a summer break.

The point here is that trends may emerge from a set of data that looks thoroughly chaotic on a lower level. This is a familiar story to psychologists, economists, and others seeking to predict human behaviour: predictions are only valid on the group level (at best!). In the example above, I averaged over time to produce a trend, while predicting human behaviour usually involves averaging over many data points (i.e., people) instead. The common principle of patterns emerging from noise holds, however.

So far, so obvious. However, the corollary of this is that when it comes to the individual case, most predictions that scientific psychology offers are so weak that they are next to useless.

For example, while I and other scientifically-oriented psychologists mock the various psychoanalysts and other psychotherapists who come up short compared to cognitive behavioural therapy in the research, the differences between the different therapies in terms of success rates are rather subtle. For a government welfare program where it is likely that thousands of clients will use the service, it makes a lot of sense to go for the most supported remedy, as the subtle differences between them become quite noticeable here. However, as a depressed individual, the difference in efficacy between the different therapies is trivial.

I think this is part of the reason why there is a considerable rift between clinical psychology and research psychology. The researcher looks at the group statistics and sees clear advantages for one remedy or another, while the clinician meets one individual after another, and is thus exposed fully to the amazing variability in how well a given approach works.

Similar concerns arise in epidemiology, the branch of medicine that deals with prevention rather than cures. The NY Times has an excellent article on the methodological difficulties that epidemiology faces, which I will only sample from. The ideal randomised double-blind control trial (where patients randomly receive treatment or placebo, and neither patient nor researcher knows who receives what) is very expensive, and thus much epidemiological research relies on weaker association studies, where patients usually fill out questionnaires about various health practices (e.g., how often do you exercise?), and the researchers then see how well the sample gets on. The goal is to correlate diagnoses or mortality rates with the questionnaire scores in order to discover what causes the disease. Or rather, what behaviours are associated with the disease.

The biggest feather in epidemiology’s hat is the link between cancer and smoking. However, as the NY Times article points out, this effect was truly magnificent, with smokers experiencing an increase in the risk of certain cancers by thousands of percent compared to non-smokers. Current studies into the health effects of hormone replacement therapy, vitamins, and omega3 fish oils deal with far smaller effect sizes, and thus other explanations for the observed associations become more probable.

The NY Times article does a good job explaining why the finding that people who take vitamins live longer doesn’t necessarily mean that vitamins keep you alive. I want to emphasise a different aspect of these studies: because the change in mortality or disease incidence is usually counted in the tens of percent at best, following this advice really isn’t going to make a dramatic difference to the individual. Much like the depressed patient choosing therapies, the effects of making these “fine tuning” health choices are so small that you might as well not bother (see also a previous post on the link between birth order and IQ).

But of course most of us do bother, myself included. No one wants to die any earlier than they necessarily have to. Unfortunately, due to the weak nature of the evidence upon which we base these decisions, it is not outside the realm of possibility that we aren’t just wasting money, but also damaging our health. The case in point would be hormone replacement therapy (HRT), which eases the strain of menopause. As the NY Times article outlines, HRT was originally found to have protective effects on mortality, if anything, and the drugs became massively popular. Later research has instead found that HRT may in fact increase mortality, only to settle on an uncomfortable juxtaposition where the experts deem that HRT is harmful if you start later in life, but helpful if you start as you go through menopause. There are probably smaller risks associated with vitamins and other supplements, but it isn’t necessarily the case that you stand nothing to lose by keeping up with the latest health craze.

The NY Times article advices the reader to simply ignore most health advice (including that regularly published in the Times, one wonders), unless the effect sizes are very large (as in smoking and cancer), or if there is what the author terms a “bolt from blue sky” effect (as in the link between asbestos and certain types of cancer), where few alternative accounts of the association are plausible.

So far, the conclusion is rather glum: psychology, epidemiology, and other sciences not covered here may have little firm advice to offer the individual. It’s worth remembering, though, that this conclusion is only valid for the individual, and at a single point in time. For example, there are studies to show that mirroring the poses and postures of the person you’re speaking to tends to result in that person liking you better. This helps me little in that one crucial employment interview since the effect is subtle, and thus unlikely to prove a deciding factor in whether I get the job or not. However, if I were Machiavellian enough to make posture mirroring my habit, over time it might work out in my favour, much like how patterns emerge in the blog stats above, if you average over long-enough time periods.

Detecting genetic disorders with 3d face scans September 16, 2007

Posted by Johan in Abnormal Psychology, AI, Applied, Behavioural Genetics, Developmental Psychology, Face Perception.
add a comment

Following on from last week’s post on smile measuring software, The Scotsman (via Gizmodo) reports on the work by Hammond and colleagues at UCL, who are developing 3d face scans as a quick, inexpensive alternative to genetic testing. This is not as crazy as it sounds at first since it is known that in a number of congenital conditions, the hallmark behavioural, physiological or cognitive deficits are also (conveniently) accompanied by characteristic appearances. The classic example of this is Down syndrome, which you need no software to recognise. More examples appear in the figure above, where you can compare the characteristic appearances of various conditions to the unaffected face in the middle.

Hammond’s software can be used to identify 30 congenital conditions, ranging from Williams syndrome (a sure topic of a future post) to Autism, according to the Scotsman. I know of no facial characteristics of autism, so I would take that part of the story with a grain of salt. The system claims an accuracy rate of over 90 percent, which is not conclusive, but certainly good enough to inform a decision to carry out genetic tests that are. The UCL press release gives some more information about how the software works:

The new method compares a child’s face to similarly aged groups of individuals with known conditions and selects which condition looks the most similar. In order to do this, collections of 3D face images of children and adults with the same genetic condition had to be gathered, as well as controls or individuals with no known genetic condition.

It really is too bad that the software uses 3d images – those cameras are neither cheap nor ubiquitous, which somewhat defeats the point of using this software as an affordable alternative to (or initial screening for) genetic testing. I can’t help but wonder if it wouldn’t be possible to achieve similar accuracy using normal portraits. If you can tell how much someone is smiling in a photo, you should be able to pick up on that extra chromosome…


Get every new post delivered to your Inbox.