Tag Archives: Sampling

More on the benefits (or otherwise) of coffee

13 Jan

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Coffee, or more specifically caffeine, crops up in a lot of places in my teaching. The Daily Mail has a strange obsession with things that cause or prevent cancer, and over the years coffee has been placed in both the ’cause’ and ‘prevent’ categories. Equally, one of my favourite Daily Express headlines ‘Two cups of coffee a day stops Alzheimer” was based solely on a study in mice. It is, however, slightly depressing when this overzealous reporting of caffeine -related stories begins to infect the BBC.

On the 12th Jan 2014 the BBC website reported a story headlines “Caffeine pill ‘could boost memory'”. The story reports a study of 160 participants, whose memory for images, over a 24 hour period, improved when given a 200 milligram caffeine tablet. The study comes from a very reputable source, and I have no reason to doubt the validity of the science involved, but I am intrigued that the BBC’s reporting of the story seem to fall half way between the extremes of the Mail and Express and actually applying some rational thinking. For example, the BBC report includes the line ‘The Johns Hopkins University study involved people who did not regularly eat or drink caffeinated products’, but makes no further comment on why this might be significant. Now, a sample of American participants who don’t drink tea, coffee or cola seems like it might be less that representative.

To give the BBC some credit, they do include ‘a voice of reason’ at the end of the story ( and I really pleased that in this case it was Dr. Ashok Jansari, a colleague from my own department).¬† Ash rightly points out the potential negative effect of caffeine, but what I find slightly odd about this is the apparent need to ‘contract out’ rational thinking, as if it isn’t something we should expect from the journalists reporting the story. After all you only need to type ‘caffeine’ into the search box of the BBC website to find a whole range of stories about the possible negative effects of caffeine including the idea of a ban on highly caffeinated drinks for under 16s.

All in all, this seems like a nice story to get students thinking rational at science (i.e. what’s the ecological validity of the original study) but also about the reporting of science and the idea that by learning some simple skills they can seemingly do the sort of thinking that BBC journalists seem to be avoiding. It’s also worth noting that ‘caffeine pill could boost memory’ is a story that is likely to be very appealing to students facing exams, and anything that gets across the message that cans of Red Bull may not be the answer to good exams results can only be a good thing ūüėČ

Regular sex makes you rich. (I give up !)

16 Aug

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My list of weird penis and sex stories has just got even longer. The Daily Mail’s story today reports a study conducted by Dr.Nich Drydakis of Anglia Ruskin University that reports an apparent correlation between income and frequency of sexual intercourse. Unusually for such stories, and very usefully for teaching purposes, the original paper is freely available on the internet.

This story could be useful for illustrating a whole range of things :

1) Correlation and causation – Does this mean that if you have more sex your income will increase ?

2) Can self-report be relied on ? – I’ve written before about the perils of self-report studies in relation to penis-size, and this seems to me like another example where it’s entirely possible that people who exaggerate about sexual activity might also exaggerate about their income

3) Generalisation – The Mail’s report of this study reports that it used 7500 participants. At face value this seems this it might add to the generalisability of the studies findings. However, I’m interested to see what my students make of all the participants being Greek. Can we draw conclusions about the UK from such a sample ?. It seems to me that even if the data is reliable, the vast cultural differences might bias the conclusions

All in all this looks like a really useful example that I look forward to trying out with the students

More questionable penis research

17 Feb

A few months ago I wrote about a frankly ridiculous penis size study that somehow made it’s way into a respectable peer-reviewed journal. I shall now be expanding by ‘penis’ lecture, having come across another ¬†questionable piece of penis research.¬†In the last week a paper called ‘ Male circumcision decreases penile sensitivity as measured in a large cohort’ published in BJU International has produced media interest around the world. The briefest of Google searches produces stories about this paper from as far afield as Singapore, India, UK and Canada.

At first sight this paper is less obviously ridiculous than Richard Lynn’s recent penis size paper, but as soon as you start to delve a whole range on flaws become apparent. Sadly,¬†¬†the Male circumcision paper is behind a paywall (and my own institution doesn’t subscribe to the journal), so I’m only working from the abstract but even with that the difficulties are fairly apparent.

The study recruited participants via ‘leaflets and advertising’ and collected data via self-report on-line. The first question I shall be asking my (predominantly female) psychology class is what might drive a man presented with a leaflet about penis sensitivity to log on to a web site and answer a series of personal and intimate questions ? Hopefully my students will recognise that the very characteristics of the population likely to respond to ‘leaflets and advertising’ on this topic might well skew the final results. Secondly, and somewhat more subtly, it would be fascinating to know if the study looked at demographic differences between the circumcised and non-circumcised groups. In a European sample (the researchers seem to be based in Belgium) it seems reasonable to assume that the circumcised group are likely to have come from particular ethic groups. You’d like to think that the non-circumcised control group would be ethnically matched (but somehow I doubt it !).

All in all these ‘penis’ studies look like a really good way to engage students with a couple of components of my rational thinking curriculum / syllabus

P.S. If anyone does have access to a copy of ‘ Male circumcision decreases penile sensitivity as measured in a large cohort’ I’d be delighted to get it

A rational thinking curriculum / syllabus

4 Dec
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I presented my work at a recent university conference, and it led me to think about how what I do could be developed. I’m a psychologist, and teach psychology students but the more I think about it the more it seems that what I do has a broader relevance. There is a long tradition in British higher education of the generic nature of graduate skills. One of my favourite quotations about the nature of graduates comes from one of John Henry Newman’s lectures in 1852, where he suggested ‘to see things as they are, to go right to the point, to disentangle a skein of thought, to detect what is sophistical, and to discard what is irrelevant’ were the key characteristics of graduates. One hundred and forty years later Newman’s quotation crops up in another attempt to define ‘graduateness’ in the HEQC’s 1985 paper ‚ÄôClarifying The Attributes Of ‘Graduateness

I’ve written elsewhere about my dislike of the traditional critical thinking literature, and thus I’m not convinced that it has much to contribute trying to contruct a rational thinking curriculum. However, psychology’s own empirical literature does offer a number of areas that can offer a start. At the end of his book ‘What is Intelligence ?’, that offers an explanation of the strange phenomena of ever-increasing IQ scores, the brilliant Jim Flynn proposes a list of ten concepts that might result in continuation of IQ growth:

1) Market forces

2) Percentages

3) Natural Selection

4) Control Groups

5) Random Samples

6) Naturalistic fallacy

7) Charisma effect

8) Placebo

9) Falsifiability

10) Tolerance school fallacy

I would add to additional concepts of my own to Jim Flynn’s list :

11) The importance of historical context

12) Heuristics and biases

I’d suggest that you can group these items into three broad areas:

1) The scientific method (4,5,8 & 9)

2) Useful concepts (1,2,3,11 & 12)

3) The structure of logical arguments (6 & 10)

As my rational thinking course has evolved over the last five years I’ve covered many of these concepts, but given that I’ve always taught psychology students I’ve tailored the examples I’ve used towards psychology. However, I’m now thinking that it wouldn’t be particularly difficult to recast those examples to appeal to a generic student audience and the address the basic curriculum I’ve outlined above. Over the next few months I’m going to try to put together generic examples that fit into the framework I’ve detailed above. I’ll post the examples here as I progress.

Is your little brother making you sick ?

16 Nov

A study has been widely reported this week that suggests that having a younger sibling causes an increase in your blood pressure. Given that heart problems as a result of high blood pressure is a leading form of premature death in many Western societies this paper would seem to be of widespread interest.

As you will see from the image above, the Daily Mail’s report of this paper is illustrated with a photograph of two caucasian children. However, merely by reading down the Mail’s story a little you discover that the paper used participants from Amazonian villages in Bolivia !

Whilst the original paper is very interesting, and the reported increases in blood pressure are intriguing, it is interesting to get students to think about what might influence rises in blood pressure in Western societies. Students should be able to readily see that trying to draw any particular conclusions about Western health problems from this sample isn’t very wise !! It’s important with a paper like this for students to realise that there is absolutely nothing wrong with the original paper, it’s they way in which the media cover it that is the problem.

They might speak our language, but they’re not like us …

15 Aug

Over the last two weeks I’ve been reminded of an experience I had four years whilst attending a conference in Boston during the Beijing Olympics. Like most academics at a conference I was never far from my laptop, and so was able to check on Olympic results many times during the day. Subsequently I had the odd experience of sitting in a hotel bar in the evening watching apparently ‘live’ Olympic TV coverage of the events where I already ¬†knew the results. As we’ve discovered again this week NBC, the American Olympic TV broadcaster, recorded all of their coverage and then showed it during ‘prime-time’ as if it was live. This made me think about cultural differences between the UK and the US, and how to get students to think about them.

My own discipline (Psychology) is dominated by American research, and it is often difficult to get my UK students to recognise that they need to question conclusions drawn from studies using American participants. It would seem that the universality of America music and television makes UK students think that they culturally indistinguishable from Americans, and thus they have no reason to question US research. At a very simple level, just asking a UK student what they think would happen if the BBC decided to only show Olympic events several hours after they had taken place should lead students someway towards recognising a very obvious cultural difference. Equally I would imagine that with a little rephrasing the same question would be illustrative for US students. This type of thinking is vital for UK psychology students, as they spend so much of their time evaluating research conducted using US participants. For example, I’ve previously written about a study suggesting that certain types of music may make you racist which I suspect may be a good example of a cultural skewed piece of research.

A couple of recent news story also look like a good way to illustrate these UK/US cultural differences. The story is a truly bizarre one, in which a US political party comes out against Critical Thinking. The 2012 platform document for the Republican Party in Texas states:

“Knowledge-Based Education ‚Äď We oppose the teaching of Higher Order Thinking Skills (HOTS) (values clarification), critical thinking skills and similar programs that are simply a relabelling of Outcome-Based Education (OBE) (mastery learning) which focus on behavior modification and have the purpose of challenging the student‚Äôs fixed beliefs and undermining parental authority.”

I don’t think it’s an exaggeration to say that had this paragraph been published by any part of either of the UK’s leading political parties, those responsible would have been very rapidly disowned by the parties national leadership.

One final anecdote also nicely illustrates a surprising UK/US cultural difference. Some months ago I was editing a paper that I wanted to be accessible for a US audience and I was thus doing through it removing UK-centric references. At one point in the paper I had referred to David Attenborough, a UK naturalist and broadcaster who has been making award-winning TV Natural History documentaries, and suggested that he was a universally trusted figure. I asked an American colleague what I  thought at the time was a very straightforward question, the name of an equally universally trusted US figure. She came up with Walter Kronkite (a newscaster who retired over thirty years ago), but struggled to think of anyone of a more recent vintage !!! Indeed, we ended up having an interesting discussion about what the absence of figures of trust said about US culture in general.

Teaching statistical thinking might have just got easier

6 Aug

Over seventy years ago Samuel Wilkes, the then President of the American Statistical Association, wrote¬†“Statistical thinking will one day be as necessary for efficient citizenship as the ability to read and write!”. (Interestingly he was paraphrasing the work of the the British writer HG Wells from 1903 !!). Given the welter of statistics that we are confronted with on a daily basis, it seem s perfectly reasonable to say that that day has arrived, and yet what I see of students entering undergraduate studies suggests that we have a long way to go in developing ‘efficient citizenship’.

My own discipline, psychology, requires students to have detailed knowledge of the statistics of null-hypothesis testing and yet in focusing on an understanding of t-tests, ANOVAs regression etc etc I suspect that more apparently ‘basic’ statistical ideas such as understanding distributions and sampling are often neglected. It has be to said that the fault does not entirely lay with those of us teaching in higher education institutions. Psychology students appear to arrive at university with an aversion to anything the looks like mathematics, that you have to assume is a product of the nature of pre-16 mathematics teaching.

Ive written before about using opinion polling problems as a route into teaching about sampling, but I’ve just come across a little book that seems like a perfect way of getting students to grasp ‘statistical thinking’.

‘How to lie with statistics’ by Darrell Huff is a tiny (124 pages) fifty year old book that contains a huge range of the type of examples that I like to use when teaching, and delivers them in a style that is accessible to modern-day students. It seems to me that this book would make an excellent basis for the first few weeks of any introductory statistics undergraduate course and ought to be compulsory reading to guarantee ‘efficient citizenship’.

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