Tag Archives: critical thinking

Being a member of a gym makes you do better at University…. The return of the Mediteranean Diet Effect

21 Jul

One of the most used examples for teaching rational thinking is the ‘Mediterranean Diet’ story. Put simply this is the idea that Northern Europeans live longer if they stick to the diet of Southern Europeans i.e. Lots of salad and olive oil. A few moment’s thought demonstrates how silly this idea is i.e. Northern Europeans who consume lots of salad and olive oil tend to come from higher income brackets, and it’s the higher economic status that is the predictor of longevity, not the diet itself.

This can to mind when I read a story in the Daily Mail this week:


This story reports a study from the Michigan State University suggesting that students who join an on-campus gym get better grades and stay in university longer. Sadly the original paper is behind a paywall, but the available abstract makes no reference to controlling for the disposable income of the students. (Working in a university I am fortunate that I have access to the full-text of this paper. As I suspected, the study doesn’t control for disposable income, indeed the paper actually acknowledges that Socio-economic status could confound the results) It seems possible that students who can afford to join a gym might have a high disposable income, and indeed that those with a higher disposable income might spend less time in paid employment and thus have more time for sporting activities (and college work !!).

All of this leaves me wondering who is at fault here. It’s interesting that whilst the paper itself acknowledges a potentially dramatic confounding variable it still makes claims about the importance of the relationship found. At times I worry that in a drive to gain publicity for their research scientists may end up actually making matters worse by facilitating a lack of understand that correlation doesn’t necessarily equal causation.


My 1st rational thinking book of year 2014 (and its only July !!)

18 Jul

I love using numerical examples of rational thinking to introduce students to the concept. There is something about how badly so many of us were taught maths at School that means that when we grasp a mathematical idea we intuitively understand that we’ve gained a skill that most people don’t have. I know it’s only half way through the year, but I’ve just read what I’m sure will be one of my rational thinking book of the year, and will be a great source of numerical examples for years to come.


Gerd Gigerenzer is Director at the Max Planck Institute for Human Development and Director of the Harding Center for Risk Literacy in Berlin, and is a big star in the academic decision making literature. Gigerenzer is often cast as the anti-Kahneman (the author of one of my books of last year), but in reality his work is an excellent adjunct to reading Kahneman, and shows the breadth of the academic working doing on in this area.

In a similar manner to Kahneman’s ‘Thinking Fast and Slow’, Gigerenzer’s ‘Risk Savvy’ summarises decades of academic work for a lay audience, and acts as something of a manifesto for creating a risk-aware population. Unlike many ‘popular’ books by leading academics I’d thoroughly recommend ‘Risk Savvy’ to anyone, and for a teacher it’s wonderful as it contains endless examples that will engage students.

If you’ve not come across Gigerenzer’s work before (and unless you’re a psychologist you probably wont have done !) you can find an excellent introduction to it in this article from the BBC’s website

The continuing saga of ‘drinkable suncream’

22 May

A couple of days ago I wrote about a laughably ludicroius story in the Daily Mail about drinkable suncream, that worked by making your molecules vibrate.  I’ve just read a wonderful blog post, that delves more into the story, and exposes that the ‘Doctor’ that runs the company involved might not be a ‘doctor’ in the tradional sense at all.

This new evidence makes it an even more compelling teaching example. It seems now like a really good illustration of Nick Davies’ point that so much of the media’s output is, in fact’ jsu rehashed press releases

Drinkable sun cream that makes your molecules vibrate !

20 May

As previous readers will know, The Daily Mail (A UK tabloid mid-range newspaper) is a great source of teaching material for me, and this morning has produced a particularly good example.



You might imagine that the headline alone, including the phrase ‘drinkable sun cream’, would be sufficient to prevent anyone reading further, but I was particularly taken by the line a few sentences into the story  ‘”Once ingested, the product’s liquid molecules vibrate on the skin, cancelling out 97 per cent of UVA and UVB rays”untitled2.

A visit to the manufacturer’s website makes for even more interesting reading. It appears that the produced is water than has had its ‘frequency enhanced’. It seems depending on the ‘enhanced frequency’ this water can be used for anything from hair loss to bowel irregularity.

Given the extravagant claim on the website, its ‘odd’ to see a disclaimer (in very small print) saying ‘These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease’.

This looks like a lovely example for initially getting students to be discerning consumers of information, but also looks like it might be useful as an intro into a discuss of the reliability of the press in general. After all, I can only think of three possible explanations for this story:

1) The Mail believe it

2) The Mail don’t believe it but think their readers will

3) The Mail were paid to publish it as an advert in the guise of a news story

Each of these options are worrying in their own way !!

On a separate note, I wonder if homeopathy ought to sue the suppliers of this product, after all it seems like they’ve adopted the ‘it’s water’ idea and taken it to it’s logical conclusion 😉



Correlation and Causation – Comedy Gold !!!

16 May


For anyone who’s ever taken a university research methods or statistics course the phrase ‘correlation doesn’t imply causation’ probably sticks in the mind. This vitally important idea is central to interpreting statistics, and yet I suspect that even for those who have studied such things to university the idea isn’t entirely clear. Politicians seem to love to ‘abuse’ correlational data, and thus an understanding of this concept is important for anyone wanting to think rationally.

Most teachers presented with the problem of getting this idea across have on obviously ridiculous correlation that they roll out. My own example is ‘There is a negative correlation between number of children in a household and number of electronic devices in a household, but this doesn’t mean that handing out toasters will reduce the birth rate’.

Someone has now done a great service to rational thinking teachers everywhere and collected a great series of spurious correlations all in one place


Why teaching rational thinking is so important….(Homeopathy yet again)

11 May


The undergraduate programme of which my rational thinking course is a part is being revised, and from September my course will change from being one semester long to being a year long. In preparation for this change I’ve been reviewing my existing material, and this week I happened to be looking at my lecture on homeopathy.

I’ve written previously about what a great vehicle for teaching rational thinking homeopathy is, but having looked at my material I did think that I needed to update it a little. One particular point that I thought needed updating was my use of a 2007 House of Commons Early Day motion as an indication that the UK Health Secretary, Jeremy Hunt, supported homeopathy. Now, I’m no great supporter of Mr Hunt, but I did think that using something seven years old to attempt to define his current views was pushing it a bit. I’d settled on the idea that I would email the Health Department to ask for the minster’s current views, when I came across a startling newspaper story.

Screen Shot 2014-05-11 at 23.24.45

The Guardian’s story ‘Jeremy Hunt sent homeopathy studies to chief medical officer’ suggests that the minister recently asked the government’s Chief Medical Officer to studies of homeopathy. Two things worry me about this, one quite nerdy and the other rather fundemental. Firstly, the two studies in question were cosponsored by Boiron, a leading homeopathic manufacturer. It might seem reasonable for the minister to pass compelling new evidence to the Chief Medical Officer for advice, but surely obvious vested interest is unlikely to be’ compelling’. My second, much more basic point, is that the minister seems to completely either overlook (or not understand), hat in asking the Chief Medical Officer, ‘Does homeopathy actually work’, he’s actually asking her to admit that everything medical science currently knows is wrong. To put it bluntly, if homeopathy works then science has got something very basic, very wrong. Given that I suspect the minister isn’t completely anti-science, what could possibly be going on here.

I genuinely haven’t had time to think about the answer to that question yet, but at the very least my homeopathy lecture will remain next year, and Jeremy Hunt has reinforced my belief in the importance of the stuff I teach !

My next job is to update my correspondence with Dr Nancy Malik (See the comments section of this post). Should be interesting 😉

The glory of people being cleverer than me !

10 Apr


I often find myself saying to students that you don’t have to be an expert in a particular topic to spot flaws in something you are being told. Just by applying rational thinking to ideas it’s often possible to detect a problem, even if you can’t quite put your finger on exactly what the problem is.

In the last couple of days I’ve come across a lovely example of this from my own thinking. In the past few months I’ve written a few times about my worries about the use of ‘big data’. I’m no statistics expert, but I’ve always worried about people trawling large datasets and coming up with post hoc conclusions. It seems to me that this flies in the face of the scientific method. I don’t have the statistical skills to articulate my concerns more than this, but my rational thinking skills are good enough to detect ‘something funny’ going on. What’s nice is that this week I’ve come across a great article by Gary Marcus in the New York Times, that articulates all the issues that I din’t have the skills to unearth.

So, two great teaching points for students:

1) You don’t have to be a ‘rocket scientist’ to identify issues within complex ideas

2) If you follow enough ‘rocket scientists’ on Twitter you will find an expert who can explain those issues for you

%d bloggers like this: