Did Boys Use To Wear Pink?

There's a belief that the colours we associate with the genders - pink for girls and blue for boys - used to be the other way around.

About 100 years ago, we're told, boys wore pink clothes, but then during the early 20th century, it flipped over. This is often used as an example of how arbitrary gender stereotypes are.

However according to psychologist Marco Del Giudice, the whole "pink-blue reversal" is an 'urban legend'. He argues that there's really only anecdotal evidence for the existence of the previous blue-girls pink-boys association.

The exceptions are four magazine articles - quoted in the paper that started the whole debate - which seem to provide documentary evidence. These associate girls with blue, but Giudice says that two of these might have been accidental typos, that swapped 'pink' with 'blue', while the other two may have represented a sneaky campaign by early feminists to subvert the blue-pink patriarchy.

Hmm. I don't really buy that. However Giudice has a stronger argument, which is that according to Google NGram, a searchable database of over 5 million books, there are lots of instances of the terms "blue for boys" and "pink for girls" going back to 1890, but none for the reverse at any time point:

Fair enough. However it's a big step from that to the idea that

the pink-blue convention may ultimately depend on innate perceptual biases toward different regions of the color spectrum in the two sexes (Hurlbert & Ling, 2007)

Del Giudice, M. (2012). The Twentieth Century Reversal of Pink-Blue Gender Coding: A Scientific Urban Legend? Archives of Sexual Behavior, 41 (6), 1321-1323 DOI: 10.1007/s10508-012-0002-z

Ritalin, The Ultimate Crimefighter?

There's been lots of interest in the idea that ADHD meds reduce crime rates.

No doubt that, even as we speak, worried pundits are writing of how this is a worrying Orwellian scenario and yadda yadda. But what's really going on?

The research is from Sweden and published in the New England Journal of Medicine: Medication for Attention Deficit–Hyperactivity Disorder and Criminality. The first thing to note is that the study is not about giving medication in order to prevent crime; it was purely looking at what happened to people given ADHD treatment for their ADHD.

In a nutshell, the authors found that people diagnosed with ADHD were about 10% less likely to be convicted of a crime during periods when they were on medication for the disorder. This was true of both men and women, and the effect was greater for the more serious offences.

It was a huge study with over 25,000 ADHD patients and the data comprise pretty much everyone in Sweden over the relevant period so in that respect it's a very good study - although speaking of Orwellian, these studies are only possible because of the Scandinavian tendency to make national registers of everything.

Now the big criticism here is that it's just a correlation, it doesn't prove that the meds were what prevented crime. It might be that ADHD meds have no effect on crime, but that people are less likely to commit crimes at periods when they have their lives sorted out (when they're 'on the rails'), one marker of which is that they're seeking treatment for their ADHD.

However, the authors found that periods of use of SSRI antidepressants were not associated with changes in conviction rates. This is quite good evidence against the 'on the rails' critique, assuming that being prescribed SSRIs is as much a marker of being on the rails as being prescribed Ritalin is.

So, in my view, this is pretty good work, as good as any observational non-randomized study. However, remember: this is just about treating ADHD. Not drugging criminals to stop crime.

Lichtenstein P, Halldner L, Zetterqvist J, Sjölander A, Serlachius E, Fazel S, Långström N, and Larsson H (2012). Medication for attention deficit-hyperactivity disorder and criminality. The New England journal of medicine, 367 (21), 2006-14 PMID: 23171097

Best. Experiment. Ever.

Studies have shown that men's testosterone levels increase after sexual stimulation. However, other research shows that merely briefly chatting to a woman also causes testosterone release, making it unclear whether sex, per se, is associated with testosterone changes.

So an intrepid band of researchers decided to find out using a unique methodology. Their paper's called Salivary Testosterone Levels in Men at a U.S. Sex Club and it's about... that.

They first set the scene:

Subjects were recruited from an internationally known "adult social club" in Las Vegas, Nevada, also referred to as a "sex club"... patrons pay a membership fee (akin to an entrance fee) to enter the 18,000 square foot, 2-story club. The first floor is open to all paying customers. The second VIP floor is available for an additional fee and includes a variety of rooms, including fetish rooms...

All are not created equal in this Garden of Eden, however:

Personal observation and communication with staff and members revealed to the investigators that there is a semi-structured hierarchy of patrons in the club. Single men (also referred to as ‘‘sharks’’) are easily identified by an orange wristband. Single women also wear an orange wrist band. Couples are identified by a green colored wristband. Single men are often considered to be a nuisance, as reported by many patrons, and are avoided in certain circumstances. Single women, moderately rare, do not share the stigma.

Anyway, the authors went there and recruited 44 men, of whom 18 ended up having sex, while 26 only looked at other patrons doing so. Saliva samples were taken before and afterwards, and levels of testosterone were measured. The results showed that testosterone increases were much larger in the do-ers than the watchers (see above).

This is an important result, the authors say, because

it runs against the grain of previous human testosterone and sexual stimuli studies in which testosterone increases in response to erotic videos and "courtship"’ behavioral interactions appeared more reliably induced than those related to active sexual behavior... We suggest that the reason for our findings, in contrast to the overarching pattern of previous work, is that lab-based paradigms may quell men’s testosterone responses... engaging in sexual behavior while wired up to machines in a sterile lab may put a damper on men’s arousal and physiological responses.

A good point.

In general, lab studies can be misleading when the behaviors under investigation are the kind of thing you can't really do in a lab. For research on fairly 'basic' memory, perception and cognitive tasks, a lab is probably as good an environment as any but for more complex behaviours it may be systematically misleading. And if a lab is bad, an MRI scanner is even less realistic.

Now, I thought the neuroscientists who threw a cocktail party on their grant money had it good, but these authors really hit a home run by using theirs to get into a sex club. It would be hard to top that but I note that surprisingly little is known about the, er, physiological correlates of lying on a beach in the Bahamas atop a pile of gold bars and bottles of Dom Pérignon. Someone needs to find out and I for one would be willing to undertake this challenge.

 Escasa, M., Casey, J., and Gray, P. (2010). Salivary Testosterone Levels in Men at a U.S. Sex Club Archives of Sexual Behavior, 40 (5), 921-926 DOI: 10.1007/s10508-010-9711-3

The Small World of Words

I've been asked to encourage people to take part in an online psychology study called The Small World of Words

I get a lot of this, and I usually don't respond to such requests, but this one looks pretty interesting.

The project aims to collect the world's biggest word association database. You see a series of words and you just have to type in the first three words that pop into your head.

Here's some more about it:

On average, an adult knows about 40,000 words. Researchers in psychology and linguistics are interested in how these words are represented mentally. In this large-scale study we aim to build a network that captures this knowledge by playing the game of word associations. You can help us with this project by participating in this short and fun study.

The study consists of giving the first three words that come to mind for a list of 14 items.
All ages and nationalities are welcome, but please note that we do require all participants to be fluent English speakers.

It's the sheer scale of this that makes it cool. They've got some 60,000 participants, and over a million associations already, but they're aiming for almost 300,000 people - which would make it not just the biggest word association study ever, but the biggest psychology study of all time, as far as I know.

It only takes about 2 minutes to complete and it's actually quite revealing. Out of 14 words I managed to associate a full 3 of them with 'pain', which disturbed me somewhat.

So take a look and spread the word (associations)...

Am I Attacking Neuroscience?

A New York Times article just out says:

Neuroscience: Under Attack

Under attack by who?

Er... me. And the rest of the usual suspects:

A gaggle of energetic and amusing, mostly anonymous, neuroscience bloggers - including Neurocritic, Neuroskeptic, Neurobonkers and Mind Hacks - now regularly point out the lapses and folly contained in mainstream neuroscientific discourse. 

I had promised not to do any more self-referential posts, but this one wasn't my fault. Just when I thought I was out, they pull me back in.

Anyway, I'm pretty happy with how Neuroskeptic's presented in the article, but not entirely.

The headline is sensationalist - I don't see myself as attacking neuroscience and I don't think any of the others do either. We are trying to defend neuroscience against errors and misrepresentations. My ideal is The Sceptical Chymist, where skepticism helped, rather than undermined, chemistry.

But the job of a headline is to be sensationalist so that's OK. Most of the piece is very good. I'm all on board with this:

Meet the "neuro doubters". The neuro doubter may like neuroscience but does not like what he or she considers its bastardization by glib, sometimes ill-informed, popularizers.

Yet I can't quite go along with this:

A number of the neuro doubters are also humanities scholars who question the way that neuroscience has seeped into their disciplines, creating phenomena like neuro law, which, in part, uses the evidence of damaged brains as the basis for legal defense of people accused of heinous crimes, or neuroaesthetics, a trendy blend of art history and neuroscience.

Admittedly this wasn't directly aimed at me because I'm not a humanities scholar, but I believe that neuroaesthetics and neurolaw are absolutely valid - in theory.

I'm not defending any particular manifestation of those, and I've criticized quite a few. But in the abstract, I see nothing wrong with neuroscience helping to explain those things. It will be difficult in practice, but it's fine to try.

Are Porn Stars Happier?

Women who appear in porn are happier than other women, enjoy sex more - and have lots more of it.

So says a new paper with the pulls-no-punches title of Pornography Actresses: An Assessment of the Damaged Goods Hypothesis

Researchers James Griffith and colleagues sampled 177 American adult actresses, and an equal number of other women of the same age, gender and relationship status. The results were pretty clear: the actresses said they started having sex earlier; had far more partners with an average of 75 vs. 5 in their lifetime (and that's not including on camera).

They were a lot more likely to be bisexual (67% vs 7%!), enjoyed sex more, and reported slightly higher levels of sexual satisfaction, happiness and self-esteem.

On the other hand, they were more worried about STDs and took more drugs (50% had tried ecstasy, 40% cocaine and 27% methamphetamine.)

Finally - and the authors emphasize this - they were no more likely than other women to have suffered childhood sexual abuse. They're not 'damaged goods' as that horrible phrase has it.

So. Well. This study is clearly going to become a hot potato, or rather a political football in The Great Porn Debate, so let's take a calm look at it.

In any survey the fundamental question is - are the respondents representative examples? Or were the porn actresses who filled out the questionnaire atypically happy? Were the comparison women unusually miserable?

We really have no way of knowing. The controls were recruited from a university and an airport, which is pretty sensible although it might introduce some bias. The actresses came via adverts placed in an L.A. clinic specifically for the adult movie industry, the now-defunct AIMHF. That seems like a selective sample - but the clinic reportedly catered to most, if not all, stars in LA because all performers had to get monthly HIV tests there.

Ultimately, though, we don't know how representative they were.

Next up, it was all self-report. So the reports might have been wrong. However, that's a feature of all survey studies, especially those about such things as happiness. It's hard to see a way around this. It's also not clear what bias it would introduce into the results. It could be that the porn actresses were motivated to exaggerate their happiness in a bid to defend their industry, which I suspect will be a common criticism - but that assumes they're happy enough with it to want to defend it, so it's somewhat circular.

Finally, and most importantly in my view, L.A. porn stars are not your average pornstars. The American professional adult movie industry is the biggest, most regulated, and most 'mainstream' in the world. Sadly elsewhere the degree of exploitation, coercion, poverty and abuse among people who end up in porn is a lot higher.

Basically, I can't see anything obviously wrong with this study as far as it goes, but all it shows is that American porn actresses are in fairly good shape. Most women in porn, however, are not American.

Griffith JD, Mitchell S, Hart CL, Adams LT, and Gu LL (2012). Pornography Actresses: An Assessment of the Damaged Goods Hypothesis. Journal of sex research PMID: 23167939

The Perils of Sharing Brain Scans

A fascinating paper by neuroscientists Van Horn and Gazzaniga chronicles their pioneering, but not entirely successful, attempt to get researchers sharing their brain scans: Why share data? Lessons learned from the fMRIDC.

It all started in 1999 when, along with some colleagues, they decided that the time was right for data sharing in neuroimaging. They got some public funding, and tried to get various major neuroscience journals to require that anyone publishing an fMRI study should make their data available to the fMRI Data Consortium (fMRIDC).

By making it mandatory, they'd ensure that there was no selection bias. Requirements to post raw data were already common in other fields of science like genetics and crystallography. So, they thought, why can't it happen here?

However, it didn't go down very well:

Upon becoming aware of our efforts and goals, fMRI researchers angered by journal requirements to provide copies of the fMRI data from their published articles began a letter writing campaign seeking to muster opposition  an effort which was featured in the news and editorial sections of several influential journals.

Editorials and commentaries over fMRI data sharing were aired in the pages of Science, Nature Neuroscience etc. expressing concern over the data sharing requirement, over what possession of the data implied, human subject concerns, and, if databasing was to be conducted at all, how it should be conducted “properly”.

This was all before my time, sadly. It sounds like a grand old academic street-fight. No doubt those on the other side remember it differently from how it's presented here, though.

The reactions of our colleagues caught us somewhat off guard. We were honestly surprised by the  negative and hostile response when we had believed that creation of a data archive would be of benefit to the neuroimaging community. Perhaps, they had a point.

Maybe the field wasn't ready for fMRI data sharing? Perhaps, it was too early to start such a project? We struggled with how best to move forward or whether to move forward at all.

Anyway, they decided they would continue, on a more modest scale. fMRIDC ended up with data from about 100 fMRI studies by the time the funders pulled the plug in 2006, only a fraction (and perhaps an unrepresentative one) of the papers published, but still, it's something.

As I said, I missed out on this debate, but if I had been in the field 10 years ago, I suspect I'd have been on the extreme wing of the pro-sharing faction, the Montagnard to the founders' Girondism. My view is that no researcher owns their data. The only person who owns the results of a brain scan is the person whose brain it is.

If I could wave a magic wand, I'd put a chip in every MRI scanner that automatically uploaded all scans to a public database as soon as they appeared (with the subject's consent, and/or with personal information about the subject stripped out). I'd fix all the software such that every time someone ran an analysis, it was publicly logged. Total transparency is best for science, I believe, and it would also make scientists lives  easier, once they got over the initial shock.

Sadly that's not possible... yet... but data sharing is a noble cause and, as Van Horn and Gazzaniga point out, even if fMRIDC is dead, the idea lives on with many new initiatives emerging, hydra-like, in its place.

Van Horn JD, and Gazzaniga MS (2012). Why share data? Lessons learned from the fMRIDC. NeuroImage PMID: 23160115

Should You Judge A Book (Woman) By The Cover?

"Do physically attractive women possess particularly attractive inner attributes?"

So ask the authors of a study just out in Psychological Science: Don't Judge a Book by Its Cover, Revisited. Their answer? People do tend to judge (female) books by their covers, but we shouldn't.

Psychologists Segal-Caspi and colleagues took 118 female Israeli students and videotaped them walking into a room and reading a weather forecast. Then other students - male and female - judged the 'targets' on attractiveness, but also tried to work out their personality, purely based on 60 seconds of video.

So what happened?

The judges judged prettier women as having stereotypically 'better' personality traits e.g. less neurotic and more friendly. Interestingly, both male and female judges did this, and there were no significant differences between the genders.

So there's a tendency to think that those we find attractive are also beautiful on the inside - but, that's all an illusion, say the authors. The targets were also rated themselves on personality, and these self ratings told a different story - there was no correlation between personality and average ratings of attractiveness.

There were however some small differences in self-reported values, with attractiveness being associated with valuing tradition and conformity, but not 'self-direction'.

So there we have it. Books, covers, don't judge 'em by 'em. It would have been better if this study had included both male and female 'targets', though, and the whole thing does rely on the validity of self-report, though no more than any other psychology paper.

The journal Psychological Science has been criticized recently, accused of publishing findings that probably aren't true and wouldn't be interesting even if they were. I don't think that applies to this, though.

On the contrary, this is the kind of study that psychologists should do more of.

The subject may seem crude, unsophisticated and not very 'scientific' but like it or not, it's one that people care about. Many people have strong views on issues like this (one way or the other), ones based essentially on hearsay, and personal recollections, i.e. on not much to speak of.

By addressing issues such as these, psychologists could really help to clear up some messy debates and damaging misconceptions.

Segal-Caspi, L., Roccas, S., and Sagiv, L. (2012). Don't Judge a Book by Its Cover, Revisited: Perceived and Reported Traits and Values of Attractive Women Psychological Science, 23 (10), 1112-1116 DOI: 10.1177/0956797612446349

Upcoming Appearances (And A Funny Picture)

Just a quick reminder - or perhaps a new announcement for those of you who aren't on Twitter - that I've been short-listed for the UK Science Blogging Prize. I'll be giving a very brief talk at the awards night next Sunday 25th November which is in the Penderel's Oak, London.

Speaking of Twitter, I'm on Twitter here: https://twitter.com/Neuro_Skeptic

I'll also be speaking in Philadelphia on December 6th at UPenn on the topic of Brain Rumors: Public (MIs)understanding of Neuroscience and Why It Matters

Finally, to save this from being a completely boring post, here is the cover of the latest British Medical Journal, which in my opinion is the funniest image ever to grace the front of an academic publication. Even if it is, literally, potty humour.

We're Probably Not Getting Dumber

There's been buzz over the past few days in the idea that humans have been getting stupider for the past few millennia. That's according to Stanford's Gerald R. Crabtree -

I would wager that if an average citizen from Athens of 1000 BC were to appear suddenly among us, he or she would be among the brightest and most intellectually alive of our colleagues and companions, with a good memory, a broad range of ideas, and a clear-sighted view of important issues. Furthermore, I would guess that he or she would be among the most emotionally stable of our friends and colleagues.

OK. How so?

Crabtree's argument in a nutshell:

In Part I, he outlines the latest evidence showing that many thousands of genes contribute to human cognitive ability, and that because mutation rates are high (higher than previously believed), any given individual probably carries harmful variants of many of these genes. This is quite possibly true ,and interesting, but by itself it's nothing to do with declining IQ.

In Part II, Crabtree says that during human evolution, all of these genes were under strong selection pressure because any human or proto-human who wasn't smart enough to hunt, fight and survive in the stone age environment, would get eaten by a predator or starve. However, after these hunter-gatherer tribes became settled farming communities (in say 6000 BC), they were no longer so vulnerable, so the less intellectually able could live... and breed... leading to ever-more unintelligence genes.

Now, there's a lot of problems here. Many have said that this is all a bit like eugenics, and indeed it is, but that doesn't necessary mean it's wrong... no, it's wrong because the argument is flawed.

For instance, it's already been pointed out that, even if it recently got easier to stay alive, that doesn't mean it's got easier to get laid lots and have lots of kids; and sexual selection is a powerful force in evolution, perhaps even stronger than survival, and it probably favours higher intelligence.

However, there are other issues.

The idea that hunter-gatherers have especially hard lives is dubious. There's good evidence that life expectancy and health fell when hunter-gatherer societies settled down and got agriculture. Today, survival doesn't exert much of a selective pressure in most parts of the world but life stayed pretty precarious (by modern standards) until at least the 19th century.  You could indeed argue that 8,000-odd years of agriculture made us smarter than ever before, and that we're enjoying the benefits . In which case we'd be smarter than someone from 1000 BC, who only had 5,000 years or so.

Crabtree does acknowledge that agriculture changed selection pressures. He suggests that it would have made it more important to be immune to the various diseases that emerged when our population density rose. But this isn't enough - for his argument to work, intelligence would also have needed to become less important with agriculture, and whether that's true is really not clear at all. Maybe it did. Maybe it didn't. There's a prejudice in modern culture against 'ignorant peasants' and 'dumb hicks', but farming is not easy.

Even if we do grant that cognitive evolutionary pressures have eased since 1000 BC, it's not clear that this would make us 'less intelligent'. 'Intelligence' is not one thing. To simplify, it might be that there's a trade-off between 'book smarts' and 'street smarts', and that you used to need the latter to survive. A society in which everyone survives would then allow more people the luxury of being book-smart. Would Einstein or Newton would have made good peasants?

Crabtree's arguments are interesting, but they're entirely speculative. There's just no hard evidence for the decline of intelligence over recent millennia. Since we can't go back in time and do IQ tests, there never will be, although he does suggest an experiment, using genetics, that might be able to check whether there's been a build-up of harmful mutations.

But until then, as he puts it,

in the meantime I’m going to have another beer and watch my favorite rerun of ‘Miami CSI’ (if I can figure out how to work the remote control).

Crabtree, G. (2012). Our fragile intellect. Part II Trends in Genetics DOI: 10.1016/j.tig.2012.10.003 

Crabtree, G. (2012). Our fragile intellect. Part I Trends in Genetics DOI: 10.1016/j.tig.2012.10.002

The New "Mood Disorder" That Isn't One

The storied history of "Disruptive Mood Dysregulation Disorder (DMDD)", a controversial new child psychiatric disorder proposed for inclusion in the new DSM-5 manual, continues.

If DSM-5 is officially published (it's due in 2013), kids will be deemed DMDD if they show

severe recurrent temper outbursts that are grossly out of proportion in intensity or duration to the situation.

At least three times a week. Would giving that label be helpful?

Pittsburg psychiatrists David Axelson and colleagues have just shown that the DMDD concept is deeply flawed. They took a large sample of kids assessed for emotional or behavior problems, and compared those who would meet the new DMDD criteria, to those who wouldn't.

"DMDD" turned out not to be correlated with anxiety or mood symptoms in either the child or their parents - rather unusual for a so-called 'Mood Dysregulation Disorder' which is found in the 'Depressive Disorder' section of the DSM-5.

However, DMDD was correlated with - and in fact "could not be delimited from" - two existing disorders, "Conduct Disorder" and "Oppositional Defiant Disorder". It wasn't even a more severe form of those disorders, it was pretty much the same thing.

So, DMDD seems to be nothing to do with mood, but instead covers a pattern of misbehavior which is already covered by not one but two labels already. Why add a misleadingly-named third?

Well, the back-story is that in the past ten years, many American kids and even toddlers have got  diagnosed with 'child bipolar disorder'  - a disease considered extremely rare everywhere else. To stop this, the DSM-5 committee want to introduce DMDD as a replacement. This is the officially stated reason for introducing it. On the evidence of this paper and others it wouldn't even achieve this dubious goal.

The possibility of just going to back to the days when psychiatrists didn't diagnose prepubescent children with bipolar (except in very rare cases) seems to not be on the table.

Axelson D, et al (2012). Examining the proposed disruptive mood dysregulation disorder diagnosis in children in the Longitudinal Assessment of Manic Symptoms study. The Journal of Clinical Psychiatry, 73 (10), 1342-50 PMID: 23140653

Beware Small Positive Studies

A Letter in the prestigious American Journal of Psychiatry offers a skeptical response to a paper published there recently.

The original article claimed amazing benefits of a safe and cheap brain stimulation technique in treating schizophrenia. But Dutch letter-writers Sommer et al aren't convinced.

It's a short piece and worth quoting:

We read with interest the article by Brunelin et al. in the July issue, which described the application of transcranial direct-current stimulation (tDCS) in the treatment of both auditory hallucinations and negative symptoms simultaneously... An effect size of 1.58 was reported for refractory hallucinations, which is remarkably large when compared with the effect sizes of antipsychotic medication (0.4–0.6).

Clinical trials involving nonconvulsive brain stimulation in schizophrenia were first introduced in 1999. Initial effect sizes were very large while samples were small. Some years later, large negative studies were published. To date, 17 placebo controlled transcranial magnetic stimulation (TMS) studies on hallucinations have been published. The mean weighted effect size is now around 0.3. Yet, the negative correlation between effect size and year of publication suggests that over time, the mean effect size may become smaller.

When selective serotonin reuptake inhibitors (SSRIs) were introduced for depression, effect sizes greater than 1.0 were reported, which created their legacy as a wonder drug. Over the course of 20 years, the mean effect size of SSRIs decreased to around 0.3. A similar trend was demonstrated for cognitive-behavioral therapy.
 
This trend likely results from publication bias. A remarkably high effect size suggests the discovery of a new wonder treatment. Studies with such findings are therefore easily published in high-impact journals. In contrast, studies of similar sample size with marginally or nonsignificant findings are less likely to be accepted for publication. Usually, after some years, negative studies with large sample sizes become available. This is when meta-analyses start to detect a decrease in efficacy.

In this view, the Brunelin et al. study is exemplary of an initial placebo-controlled study applying a new technique: it included a small sample, found remarkably large effects, and is published in a high-impact journal.
 
We sincerely hope that tDCS is the exception to the rule— as a cheap, safe, and highly effective method to treat both refractory hallucinations and negative symptoms is most welcome. However, given the previous observations for other new treatments, it is realistic to expect that 10 years from now the mean weighted effect size of tDCS will be around 0.3.

Sommer et al are talking about the famous 'decline effect', in which the size of an effect mysteriously shrinks the more people study it, which I've written about before.

I suspect the authors are right in this case; playing science devil's advocate though, it's unfair and unscientific to assume that a new treatment that looks promising will eventually turn out to be mediocre, just because that's happened to other treatments before.

After all, some things look awesome because they are - penicillin, for example, was heralded as a new wonder drug... and it was.

I very much doubt that tDCS is the new penicillin. But I do think that this kind of speculation is ultimately not very useful. Rather than bemoaning the errors of the past and wondering whether they'll be repeated, we should reform science to make sure they don't.

Sommer IE, Aleman A, Slotema CM, and Schutter DJ (2012). Transcranial stimulation for psychosis: the relationship between effect size and published findings. The American Journal of Psychiatry, 169 (11) PMID: 23128925

Migraines On Twitter

People talk about migraines on Twitter more on weekdays than weekends and holidays - and the peak time of day for the horrible headaches is 7 in the morning.

The working-day effect on migraines has been reported before - perhaps a reflection of stress or, less charitably, people wanting a day off work... although some people suffer weekend migraines.

Of the working week, Tuesdays saw the most migraines, while Fridays were the least bad. About 80% of Twitter migraine mentions came from women - which matches the fact that women are at higher risk.

That's according to a little study just published that used a public database of tweets, timeu.se, that Neuroskeptic readers may remember.

In fact, an author of this study said in an email to me that it was actually inspired by one of my posts... but I'm aware that telling you that, combined with the previous post, means I'm in danger of blowing my own trumpet or 'disappearing up my own arse' as we say in the UK. So rest assured that this will be the last such self-referential piece for at least... a day or two.

Linnman, C., Maleki, N., Becerra, L., and Borsook, D. (2012). Migraine Tweets - What can online behavior tell us about disease? Cephalalgia DOI: 10.1177/0333102412465207

Blogging's First Academic Paper

In an historic achievement, I can announce that I have become (to my knowledge) the first blogger ever to publish in a peer-reviewed academic journal under a blogging pseudonym.

Skeptic, N. (2012) The Nine Circles of Scientific Hell Perspectives on Psychological Science 7 (6) 643-644

This is based on a post from two years ago (far and away the most popular post I've ever done).

Now as historic achievements go, this is fairly niche, but I do think it's important.

Most of the problems with the way science works today are problems of communication. We're trying to do 21st century work with a 19th century publishing model, and the cracks are showing.

Academic papers are a fine way of presenting the final results of research - they're here to stay. But scientists ought to be communicating (with each other and with the public) in many other ways as well, and I think that anything we can do to break down the hegemony of the 'final paper' - whether it be blogging, arxiv, the Open Science Framework or raw data sharing - is a step forward.

In that regard, I think it's great that the boundaries between 'real' papers and alternative forms of scientific communication have just become a little blurrier.

The piece appears in a special issue of Perspectives on Psychological Science full to bursting with other papers that readers of this blog are likely to find interesting... and it's all free to access (at least for now).

Neuroskeptic (2012). The Nine Circles of Scientific Hell Perspectives on Psychological Science, 7 (6), 643-644 DOI: 10.1177/1745691612459519

The Persistence of "Past-Life" Memories

Many children spontaneously report memories of 'past lives'. For believers, this is evidence for reincarnation; for others, it's a psychological oddity.

But what happens when they grow up?

Icelandic psychologists Haraldsson and Abu-Izzedin looked into it. They took 28 adults, members of the Druze community of Lebanon. All of the participants had been interviewed about their past life memories by the famous reincarnationist Professor Ian Stevenson in the 70s, back when they were just 3-9 years old.

Did they still 'remember'? Most of them thought they did:

Twelve of the 28 participants are sure that they still have clear memories of their past life, and an additional 12 believe that they still have some of their childhood memories, so 86% of our sample still report some memories of a past life... one man was not sure about the source of the memories, two remembered speaking of past life memories as a child, but do not have these memories now, and one thought she might only remember something of her past life because these memories were much talked about in her family.

However - it turned out that they weren't always the same memories they'd originally reported.

As children they reported on average 30 distinct memories of past lives. As adults they could only remember 8, but of those, only half matched the ones they'd talked about previously:

This indicates that half of the statements remembered today are either fictional or distortions of the original childhood memories, or that the old lists of statements might have been incomplete.

In other words, they probably suffered from a false memory of a false memory - the mind is weird. Despite this, past lives seemed more memorable than real early-childhood:

We asked our participants what they remembered from their preschool years. We were surprised how little they remembered, and some could not remember anything. Our general impression is that past-life memories are better remembered into adult life than are normal memories from preschool years.

There was no evidence that these people suffered from any particular psychological problems as a result of their experiences, but 21% did say that overall, they preferred their past lives to their real ones.

Personally, I have a very vivid memory, not of a past life per se but rather of a very early stage in my own: I remember lying in my cot, unable to get out, rather bored, and waiting for my parents to get me up for the day.

This may really be my earliest memory, but the more I've thought about it, the less likely it seems. Could I have known what time it was, and that my parents would eventually come, when I was unable to even stand up by myself?

Maybe. But maybe it was just a later childhood dream about being a baby that seemed real. At that age, the line between dreams and reality is blurry as parents who've had to comfort a child after a nightmare will attest. I suspect this accounts for many of these 'past lives'.

Haraldsson E, and Abu-Izzedin M (2012). Persistence of "past-life" memories in adults who, in their childhood, claimed memories of a past life. The Journal of nervous and mental disease, 200 (11), 985-9 PMID: 23124184

Exercise And Depression Revisited

A new study has found little evidence that aerobic exercise helps treat depression, contrary to popular belief.

Danish researchers Krogh and colleagues randomly 115 assigned depressed people to one of two exercise programs. One was a strenuous aerobic workout - cycling for 30 minutes, 3 times per week, for 3 months. The other was various stretching exercises.

The idea was that stretching was a kind of placebo control group on the grounds that, while it is an intervention, it's not the kind of exercise that gets you fit. It doesn't burn many calories, it doesn't improve your cardiovascular system, etc. Aerobic exercise is the kind that's most commonly been proposed as having an antidepressant effect.

So what happened? Not much. Both groups got less depressed but there was zero difference between the two conditions. The cyclists did get physically fitter than the stretchers, losing more weight and improving on other measures. But they didn't feel any better.

If this is true, it might mean that the antidepressant effects of aerobic exercise are psychological rather than physical - it's about the idea of 'exercising', not the process of becoming fitter.

While many trials have found modest beneficial effects of exercise vs a "control condition", the control condition was often just doing nothing much - such as being put on a waiting-list. So the placebo effect or the motivational benefits of 'doing something', rather than the effects of exercise per se, could be behind it. In the current study though the stretching avoided that problem.

As I said in a post about a previous paper, I said that Exercise and Depression: It's Complicated

The idea that exercise is a useful treatment for depression: it's got something for everyone. For doctors, it's attractive because it means they can recommend exercise - which is free, quick, and easy, at least for them - instead of spending the time and money on drugs or therapy. Governments like it for the same reason, and because it's another way of improving the nation's fitness. For people who don't like psychiatry, exercise offers a lovely alternative to psych drugs - why take those nasty antidepressants if exercise will do just as well? But this doesn't mean it's true.

This was a moderate sized study, and one study by itself doesn't prove much - any more than one single political poll does. From personal experience I think there's a good chance strenuous aerobic exercise can boost mood... but this is a reminder that the picture on exercise and depression is not quite as clear as the recent enthusiasm for it suggests...

Krogh J, Videbech P, Thomsen C, Gluud C, & Nordentoft M (2012). DEMO-II Trial. Aerobic Exercise versus Stretching Exercise in Patients with Major Depression-A Randomised Clinical Trial. PloS one, 7 (10) PMID: 23118981

John Bargh's "Transient and Ephemeral" Blogs

Leading social psychologist and Yale Professor John Bargh has been at the center of a number of controversies lately.

Most recently, researcher Brent Donnellan covered a case in which he was unable to replicate one of Bargh's experiments, which prompted Bargh to share his original raw data with him, but on the condition that he never discussed it publicly: What’s the First Rule about John Bargh’s Data? You do not talk about John Bargh’s data

But a couple of months back, even more sparks flew over an unrelated non-replication. Some other people didn't reproduce a different Bargh study.

In response to that non-replication, Bargh published two blog posts called "Nothing In Their Heads" and "Angry Birds", criticizing both the study itself and the journal it appeared in, PLoS ONE. It was a combative defence of his work.

However, Bargh seems to have since decided it was a bit too defensive, because the posts have been deleted. They just vanished: to my knowledge Bargh hasn't announced this, nor explained why.

Now interestingly enough, Bargh has just published a short paper in which he offers he thoughts on blogging - it's rather topical...

Debate among psychologists takes place formally in the published record of journal articles and books... this is the permanent record, as opposed to the relatively transient and ephemeral world of blogs.

As I understand (and use) them, blogs are like newspaper columns or spontaneous radio interviews, and meant to be a forum wherein one can provide the interested public with opinions, feelings, and conjectures; blogs are thus a potentially valuable outlet for ideas when used and evaluated appropriately...

[but they are] personal property whereas journal articles are public property
– as illustrated by one’s ability to edit, change, or delete one’s personal blog entries and one’s concomitant inability to do the same with published works (except to make necessary corrections with the consent of the journal editor).

Fair enough. However, the fact is, a public statement is a public statement. You can change your mind, but you can't change the past. In my book, to try to erase your past statements from the record is both deceptive - and counterproductive.

The internet never forgets... well, actually, I can't find copies of the deleted posts (Edit: See the comments, someone has saved them), so maybe it does, however there are dozens of references to them online, many highly critical. At best, what Bargh has achieved is that his critics are now the only sources for information about his work.

Bargh's new paper, by the way, is a response to this piece I blogged about about the question of free will.

Bargh, J. (2012). Social psychology cares about causal conscious thought, not free will per se British Journal of Social Psychology DOI: 10.1111/bjso.12011

Autism Brain Scans Flawed? You Read It Here First

According to a piece in Nature today, a major line of research about autism might be seriously flawed:

One of the most popular and widely accepted theories on the cause of autism spectrum disorders attributes the condition to disrupted connectivity between different regions of the brain.

This 'connectivity hypothesis' claims that the social and cognitive abnormalities in people with autism can be explained by a dearth of connections between distant regions of the brain. Some flavours of this theory also predict more connections between nearby brain regions.

Recent studies, however, have found that when a person moves their head while undergoing functional magnetic resonance imaging (fMRI) - a method that maps how different neuroanatomical structures of the brain interact in real time, its functional connectivity - it looks like the neural activity observed in autism. That's a sobering discovery...

So the characteristic pattern of "abnormal connectivity" in autism might not be real: it might just reflect the fact that people with autism move around more during the scan.

A sobering idea, indeed... but not an entirely new one. I suggested it over a year ago:

Head motion affects estimates of functional connectivity. The more motion, the weaker the measured connectivity in long-range networks, while shorter range connections were stronger... Disconcertingly, this is exactly what's been proposed to happen in autism (although in fairness, not all the evidence for this comes from fMRI). This clearly doesn't prove that the autism studies are all dodgy, but it's an issue. People with autism, and people with almost any mental or physical disorder, on average tend to move more than healthy controls.

Ben Deen, and Kevin Pelphrey (2012). Perspective: Brain scans need a rethink Nature