Links You Might Like #2, and a note on Powerwatch

The Chronicle of Higher Education has a must-read piece about the integration of sociology and behavioral genetics. In it we learn that the American Journal of Sociology has just run a special issue devoted to that theme - wow. Looks fascinating (I haven't read it yet). As John Hawks notes, however, the traditional feuding between biological and social theorists of behaviour doesn't seem to be over yet...

There was an interesting discussion of the psychology of philosophy over at The Garden of Forking Paths.

Finally, Powerwatch UK have, very decently, included a link to my December 21st criticisms of a paper about leukemia and power lines, in their coverage of that study.

Critiquing a Classic: "The Seductive Allure of Neuroscience Explanations"

One of the most blogged-about psychology papers of 2008 was Weisberg et. al.'s The Seductive Allure of Neuroscience Explanations.

As most of you probably already know, Weisberg et. al. set out to test whether adding an impressive-sounding, but completely irrelevant, sentence about neuroscience to explanations for common aspects of human behaviour made people more likely to accept those explanations as good ones. As they noted in their Introduction:

Although it is hardly mysterious that members of the public should find psychological research fascinating, this fascination seems particularly acute for findings that were obtained using a neuropsychological measure. Indeed, one can hardly open a newspaper’s science section without seeing a report on a neuroscience discovery or on a new application of neuroscience findings to economics, politics, or law. Research on nonneural cognitive psychology does not seem to pique the public’s interest in the same way, even though the two fields are concerned with similar questions.

They found that the pointless neuroscience made people rate bad psychological "explanations" as being better. The bad psychological explanations were simply descriptions of the phenomena in need of explanation (something like "People like dogs because they have a preference for domestic canines"). Without the neuroscience, people could tell that the bad explanations were bad, compared to other, good explanations. The neuroscience blinded them to this. This confusion was equally present in "normal" volunteers and in cognitive neuroscience students, although cognitive neuroscience experts (PhDs and professors) seemed to be immune.

But is this really true?

This kind of research - which claims to provide hard, scientific evidence for the existence of a commonly believed in psychological phenomenon, usually some annoyingly irrational human quirk - is dangerous; it should always be read with extra care. The danger is that the results can seem so obviously true ("Well of course!") and so important ("How many times have I complained about this?") that the methodological strengths and weaknesses of the study go unnoticed. People see a peer-reviewed paper which seemingly confirms the existence of one of their pet peeves, and they believe it - becoming even more peeved in the process.(*)

In this case, the peeve is obvious: the popular media certainly seem to inordinately keen on neuroimaging studies, and often seem to throw in pictures of brain scans and references to brain regions just to make their story seem more exciting. The number of people who confuse neural localization with explanation is depressing. Those not involved in cognitive neuroscience must find this rather frustrating. Even neuroimagers roll their eyes at it (although some may be secretly glad of it!)

So Weisberg et al. struck a chord with most readers, including most of the potentially skeptical ones - which is exactly why it needs to be read very carefully critiqued. Personally, having done so, I think that it's an excellent paper, but the data presented only allow fairly modest conclusions to be drawn, so far. The authors have not shown that neuroscience, specifically, is seductive or alluring.

Most fundamentally, the explanations including the dodgy neuroscience differed from the non-neurosciencey explanations in more than just neuroscience. Most obviously, they were longer, which may have made them seem "better" to the untrained, or bored, eye; indeed the authors themselves cite a paper, Kikas (2003), in which the length of explanations altered how people perceived them. Secondly, the explanations with added neuroscience were more "complex" - they included two separate "explanations", a psychological one and a neuroscience one. This complexity, rather than the presence of neuroscience per se, might have contributed to their impressiveness.

Perhaps the authors should have used three conditions - psychology, "double psychology" (with additional psychological explanations or technical terminology), and neuroscience (with additional neuroscience). As it stands, the authors have strictly shown is that longer, more jargon-filled explanations are rated as better - which is an interesting finding, but is not necessarily specific to neuroscience.

In their discussion (and to their credit) the authors fully acknowledge these points (emphasis mine)

Other kinds of information besides neuroscience could have similar effects. We focused the current experiments on neuroscience because it provides a particularly fertile testing ground, due to its current stature both in psychological research and in the popular press. However, we believe that our results are not necessarily limited to neuroscience or even to psychology. Rather, people may be responding to some more general property of the neuroscience information that encouraged them to find the explanations in the With Neuroscience condition more satisfying.

But this is rather a large caveat. If all the authors have shown is that people can be "Blinded with Science" (yes...like the song) in a non-specific manner, that has little to do with neuroscience. The authors go on to discuss various interesting, and plausible, theories about what might make seemingly "scientific" explanations seductive, and why neuroscience might be especially prone to this - but they are, as they acknowledge, just speculations. At this stage, we don't know, and we don't know how important this effect is in the real world, when people are reading newspapers and looking at pictures of brain scans.

Secondly, the group differences - between the "normal people", the neuroscience students, and the neuroscience experts - are hard to interpret. There were 81 normal people, mean age 20, but we don't know who they were or how they were recruited - were they students, internet users, the authors' friends? (10 of them didn't give their age and for 2 gender was "unreported" -?) We don't know whether their level of education, their interests, or values were different from the cognitive neuroscience students in the second group (mean age 20), who may likewise have been different in terms of education, intelligence and beliefs from the expert neuroscientists in the third group (mean age 27). Maybe such personal factors, rather than neuroscience knowledge, explained the group similarities and differences?

Finally, the effects seen in this paper were, on the face of it, small - people rated the explanations on a 7 point scale from -3 (bad) to +3 (excellent), but the mean scores were all between -1 and +1. The dodgy neuroscience added about 1 point on a 7 point scale of satisfactoriness. Is that "a lot" or "a little"? It's impossible to say.

All of that said - this is still a great paper, and the point of this post is not to criticize or "debunk" Weisberg et. al.'s excellent work. If you haven't read their paper, you should read it, in full, right now, and I'm looking forward to further stuff from the same group. What I'm trying to do is to warn against another kind of seductive allure, probably the oldest and most dangerous of all - the allure of that which confirms what we already thought we knew.

(*)Or do they? Or is this just one of my pet peeves? Maybe I need to do an experiment about the allure of psychology papers confirming the allure of psychologist's pet peeves...

Deena Skolnick Weisberg, Frank C. Keil, Joshua Goodstein, Elizabeth Rawson, Jeremy R. Gray (2008). The Seductive Allure of Neuroscience Explanations Journal of Cognitive Neuroscience, 20 (3), 470-477 DOI: 10.1162/jocn.2008.20040

Lessons from the Video Game Brain

See also Lessons from the Placebo Gene. Also, if you like this kind of thing, see my other fMRI-curmudgeonry(1, 2)

The life of a neurocurmudgeon is a hard one, but once in a while, fate smiles upon us. This article in the Daily Telegraph neatly embodies several of the mistakes that people make about the brain, all in one bite-size portion.

The article is about a recent fMRI study published in the Journal of Psychiatric Research. 22 healthy Stanford student volunteers (half of them male) played a "video game" while being scanned. The game wasn't an actual game like Left 4 Dead(*), but rather a kind of very primitive cross between Pong and Risk, designed specifically for the purposes of the experiment:

Balls appeared on one-half of the screen from the side at 40 pixel/s, and 10 balls were constantly on the screen at any given time. One’s own space was defined as the space behind the wall and opposite side to where the balls appeared. The ball disappeared whenever clicked by the subject. Anytime a ball hit the wall before it could be clicked, the ball was removed and the wall moved at 20 pixel/s, making the space narrower. Anytime all the balls were at least 100 pixels apart from the wall ... the wall moved such that the space became wider.

Essentially they had to click on balls to stop them moving a line. This may not sound like much fun, but the author's justification for using this task was that it allowed them to have a control condition in which the instructions and were the same (click on the balls) but there was no "success" or "failure" because the line defining the "territory" was always fixed. That's actually a pretty good idea. The students did the task 40 times during the scan for 24s at a time, alternating between the two conditions, "no success" (line fixed) and "game with success/failure" (line moves).

The results: While men & women were equally good at clicking balls, men were more successful at gaining "territory" than the women. In both genders, doing the task vs. just resting in the scanner activated various visual and motor-related areas - no surprise. Playing the game vs. doing the control task in which there was no success or failure produced more activation in a handful of areas but only "at a more liberal threshold" i.e. this activation was not statistically reliable. A region-of-interest analysis found activation in the left nucleus accumbens and right orbitofrontal cortex, which are "reward-related" areas. In males, the game-specific activation was greater than in females in the right nucleus accumbens, the orbitofrontal cortex, and the right amygdala.

These areas are indeed "neural circuitries involved in reward and addiction" as the authors put it, but they're also activated whenever you experience anything pleasant or enjoyable, such as drinking water when you're thirsty. Water is not known to be addictive. So whether this study is relevant to video-game "addiction" is anyone's guess. As far as I can tell, all it shows is that men are more interested in simple, repetitive, abstract video games. But that's hardly news: in 2007 there was an International Pac-Man Championship with 30,000 entrants; the top 10 competitors were all male. (If anything in that last sentence surprises you, you haven't spent enough time on the internet.)

Anyway, that's the study. This is what the Telegraph made of it:

Playing on computer consoles activates parts of the male brain which are linked to rewarding feelings and addiction, scans have shown. The more opponents they vanquish and points they score, the more stimulated this region becomes. In contrast, these parts of women's brains are much less likely to be triggered by sessions on the Sony PlayStation, Nintendo Wii or Xbox.

Well, not quite. No opponents were vanquished and no Wii's were played. But so far this is just another fMRI study that attracted the attention of a journalist who knew how to spin a good story. Readers of Neuroskeptic will know this is not uncommon. However, it doesn't end there. Here's the really instructive bit:

Professor Allan Reiss of the Centre for Interdisciplinary Brain Sciences Research at Stanford University, California, who led the research, said that women understood computer games just as well as men but did not have the same neurological drive to win.
"These gender differences may help explain why males are more attracted to, and more likely to become 'hooked' on video games than females," he said.
"I think it's fair to say that males tend to be more intrinsically territorial. It doesn't take a genius to figure out who historically are the conquerors and tyrants of our species – they're the males.
"Most of the computer games that are really popular with males are territory and aggression-type games."

Now this is a theory - men like video games because we're intrinsically drawn to competition, conquest and territory-grabbing. This may or may not be true; personally, in the light of what I know of history and anthropology, I suspect it is, but even if you disagree, you can see that this is an important theory: it makes a big difference whether it's true or not.

However, the fMRI results have nothing to do with this theory. They neither support nor refute it, and nor could they; this experiment is essentially irrelevant to the theory in question. Prof. Allan Reiss is simply stating his personal opinions about human nature - however intelligent & informed these opinions may be. (Just to be clear, it's quite possible that Reiss didn't expect to be quoted in the way he was; he may have, not unreasonably, thought that he was just giving his informal opinion.) The Telegraph's sub-headline?

Men's passion for computer games stems from a deep-rooted urge to conquer, according to research

There are some lessons here.

1. If you want to know about something, study it.

If you want to learn about human behaviour, study human behaviour. Stanley Milgram discovered important things about behaviour; if he had never even heard about the brain, it wouldn't have stopped him from doing that.

Neuroscience can tell us about how behaviour happens. We get thirsty when we haven't drunk water for a while. Neuroscience, and only neuroscience, will tell you how. Some people get depressed or manic. One day, I hope, neuroscience will tell us the complete story of how - maybe mania will turn out to be caused by hyper-stimulation of a certain dopamine receptor - and we'll be able to stop it happening with some pill with a 100% success rate.

However, neuroscience can't tell you what human behaviour is: it cannot describe behaviour, it can only explain it. People know about thirst and depression and mania long before they knew anything about the brain. More importantly, and more subtly, neuroscience can only explain behaviour in the "how" sense; only rarely can it tell you why behaviour is the way that it is.

If someone is behaving in a certain way because of brain damage or disease, that's one of these rare cases. In that case "damage to area X caused by disease Y" is "why". But in most cases, it's not. To say that men like video games because their reward systems are more sensitive to video games is not a "why" explanation. It's a "how" explanation, and it leaves completely open the question of why the male brain is more sensitive to video games. The answer might be "innate biological differences due to evolution", or it might be "sexist upbringing", or "paternalistic culture", or anything else.

(This is often overlooked in discussions about psychiatry. Some people object to the idea that clinical depression is a neuro-chemical state, pointing out that depression can be caused by stress, rejection and other events in life. This is confused; there is no reason why stress or rejection could not cause a state of low serotonin. By extension, saying that someone has "low serotonin" always leaves open the question of why.)

2. Brains are people too

This leads on to a more subtle point. Some people understand the difference between how and why explanations, but feel that if the "how" is something to do with the brain, the "why" must be to do with the brain too. They look at brain scans showing that people behave in a certain way because their brain is a certain way (e.g. men like games because their reward system is more activated by games), and they think that there must be a "biological" explanation for why this is.

There might be, but there might not be. Brains are alive; they see and hear; they think; they talk; they feel. Your brain does everything you do, because you are "your" brain. The astonishing thing about brains is that they are both material, biological objects, and concious, living people, at the same time.

Your brain is not your liver, which is only affected by chemical and biological influences, like hormones, toxins, and bacteria. Your liver doesn't care whether you're a Christian or a Muslim, it cares about whether you drink alcohol. Your brain does care about your religion because some pattern of connections in your brain gives you the religion that you have.

Brain scans, by confronting us with the biological, material nature of the brain, make us look for biological, material why explanations. We forget that the brain might be the way it is because of cultural or historical or psychological or sociological or economic factors, because we forget that brains are people. We tend to think of people as being something beyond and above their brains. Ironically, it's this primitive dualism that leads to the most crude materialistic explanations for human behaviour.

3. Beware neuro-fetishists

There's a doctoral thesis in "Science Studies" to be written about how it came to happen, but that we fetishize the brain is obvious. For much of the 20th century, psychology was seen in the same way. Freud joined Nietschze, Marx and Heidegger in the ranks of Germanic names that literary theorists and lefty intellectuals loved to drop.

Then the bottom fell out of psychoanalysis, Prozac and fMRI arrived and the Decade of the Brain was upon us. Today, neuroscience is the new psychology - or perhaps psychology is becoming a branch of neuroscience. (If I asked you to depict psychology visually, you'd probably draw a brain - if you do a Google image search for "psychology", 10 out of the 21 front page hits depict either a brain or a head; this might not surprise you but it would have seemed odd 50 years ago.) There's a presumption that neuroscience is key to answering both how and why questions about the mind.

Neuroscience is now hot, but what people are mostly interested in are psychological and philosophical questions. People care about The Big Questions like -

"Is there life after death? Do we have free will? Is human nature fixed? Are men smarter/more aggressive/more promiscuous/better drivers than women? Why do people become criminals/geniuses/mad?"

These are good questions - but neuroscience has little to say about them, because they're not questions about the brain. They're questions for philosophers, or geneticists, or psychologists. No brain scan is going to tell you whether men are better drivers than women. It might tell you something about the processes by which make decisions while driving, but only a neuroscientist is likely to find that interesting.

P.S It turns out that people were saying similar things about this research back in Feburary. A blogger who writes about research on video games (neat) wrote about it way back then. So why did the Telegraph decide to resurrect the story as if it were new? That's just another one of life's mysteries.

[BPSDB]

(*) Which is so awesome.

F HOEFT, C WATSON, S KESLER, K BETTINGER, A REISS (2008). Gender differences in the mesocorticolimbic system during computer game-play Journal of Psychiatric Research, 42 (4), 253-258 DOI: 10.1016/j.jpsychires.2007.11.010

Links You Might Like

From the British Medical Journal, a man describes his wife's experience with depression and its succesful treatment with ECT. ("To me as a carer, it feels as if some malign, intangible entity has attached itself to my wife, constantly attacking her. Ana and I are very close: I can feel her mood as soon as I enter the same room as her, and when things are bad, the depression is like an oppressive weight that lies on us both. It sucks the colour out of life. I’ve never seen mentioned in any medical text just how truly terrifying depression is. It’s very, very scary, watching the one you love withdraw from life and turn into an inert stranger—and you can never, ever, relax, because you know that the spectre of suicide is always hanging over all your lives.")

Are Humans Hard-Wired to Ignore the Threat of Climate Change? - Excellent article from a few months back discussing research on risk perception and how it might be applied to make people take global warming seriously - basically, you need to scare people and then tell them how to solve the problem. Politicians have known that for a long time before psychologists said it, of course, but some of the research is interesting.

"If I look at the mass I will never act" - Psychologist Paul Slovic on the psychology of famine and genocide. Apparantly, people will donate more money to feed one child than they will to feed two children. Stalin knew that one death is a tragedy, a million deaths is a statistic - now we know that even two deaths is a statistic.

If you liked those last two, Greater Good Magazine has lots more of that kind of thing. It's from Berkeley and it's got a bit of a "positive psychology" vibe, but it's full of good stuff.

Finally, if you need cheering up, here's Chris Rock on a promising new antidepressant...

Are Faces Special?

There's been a glut of face-based science lately. There was the first American face transplant (the second if you count the ill-fated Travolta/Cage one...) Then an Atlanta group allegedly found that chimpanzees have a part of the brain specialized for recognizing the faces of their fellow chimps.

As I'll explain, this would be extremely important if true. This research is just the latest chapter in a long and contentious debate going back many years - a debate which, believe it or not, may hold the answer to Life, the Universe, and Everything! I'll get onto that later.

The human brain may, or may not, have regions which are "hard-wired" specifically for the visual processing of faces; the question of whether it does is generally known as the "Are Faces Special?" debate.(*) The majority of neuroscientists today would say that yes, they are, and that yes, we do have at least one such face area. I agree with this, but the debate's not yet ever - although as usual the reporting on this study glosses over such complexities.

On the face of it (ha), the evidence for specialized processing of faces in the human brain is very strong. We're very good at distinguishing and recognizing faces, despite the fact that they are all extremely similar - and when faces are shown upside-down, we are much worse at dealing with them. This suggests, to most people, that we have a specialized capacity for processing faces.

Following certain brain lesions, some patients lose their ability to recognize faces, a condition known as prosopagnosia. This most commonly follows damage to a part of the temporal lobe of the brain called the fusiform gyrus. Prosopagnosics may be able to identify and recognize other kinds of objects, but they just can't "get" faces. (Prosopagnosia can also be congenital i.e. present from birth). To a prosopagnosic, every face is as inscrutable as upside-down faces are to the rest of us.

Meanwhile, neuroimaging has consistently shown a small portion of the aforementioned fusiform gyrus on the right side, dubbed the "fusiform face area (FFA)", is more activated when people are looking at pictures of faces than when they are looking at inanimate objects, other body parts, or pictures of faces which have been scrambled up so as to no longer look like faces.

So all of the evidence seems to mesh together ("converge") splendidly: there's a face area in the human brain, located in the Fusiform Face Area, which is responsible for our unusually good face-processing abilities. Hurrah. However, there's a parade-raining alternative view, namely that faces are not special, we are only good at processing them because we have so much experience doing so, and the FFA's role lies in detecting the differences between similar objects about which we have learned to be highly familiar - faces being just one example.

The details of this debate are fairly bewildering. For what it's worth, the "expertise" account has always seemed rather contrived to me and expertise theorists seem to be on the defensive against the more confident and plausible "specialist" neuroscientists. But that's just my opinion. For an excellent overview of the neuroscience of faces see here; for a skeptical view of the Fusiform Face Area see this; for skepticism of the skepticism here.

Anyway, into this debate stepped Lisa Parr et. al. who used ¹⁸F-flurodeoxyglucose PET imaging to measure neural activity in five adult chimpanzees. Their goal was to see whether chimps possess a Fusiform Face Area or not. Chimps, unlike "lower" monkeys, are good at recognizing chimp (and human) faces. The five luckless chimps had to perform two tasks, one of which involved visually "matching" pictures of chimp faces in order to earn Kool-Aid. The other control task involved the same procedure but with matching non-face pictures ("Clip Art").

Subjects have been trained to control the movements of a cursor on the computer screen by manipulating the joystick ... At the beginning of a trial, a single image (the sample) appears on the computer screen on a black background. ... After this, the sample clears the screen and two comparison images appear on the monitor ... One of these comparisons matches the sample (the target), and the other (the foil) is a different image from the same category, either another face or another clip art object. ... Subjects must contact the image that matches the sample by contacting it with the joystick-controlled cursor.

Compared to the control Clip Art task, the chimp's brains were more active during the face task in a wide range of areas. The most "face-selective" area was the "Dorsal primary motor/medial parietal cortex (Left)" which has nothing to do with faces, vision, or any of that kind of stuff. The authors try to put a brave face on this (emphasis mine)...

The first [whole brain] analysis revealed numerous brain regions that showed greater metabolic activity during the face-matching task when compared directly to the object-matching ... [including] the posterior superior temporal sulcus (STS) and orbitofrontal cortex ... These regions comprise part of the distributed cortical network for face processing in humans. Notably absent from this analysis was activity in the fusiform gyrus, the primary region where face-selective activity is found in humans when the comparable analysis is used.

...but this is clearly a disappointing result. No chimp FFA found. Yet this is hardly surprising, considering that there were only five subjects in this experiment, and there's obviously a big difference between a human volunteer, and a chimpanzee who's spent years being experimented on, is locked in a cage, is highly trained on the computerized task, and who is doing the experiment for Kool-Aid.(**) The absence of evidence in this experiment is not evidence of absence.

All was not lost, however, because the authors then did a different analysis, looking for individual voxels (small parts of the brain) which were "face selective" or "object selective". (I suspect this was a post-hoc analysis, a naughty practice which I have warned about before, but here it's arguably OK). Short story - they found a lot of such voxels, most of them in areas which are nothing to do with faces or vision, but there were quite a few in the fusiform gyrus, which is where you might expect them to be based on human work (see above.) But honestly, neuroimaging data is noisy enough at the best of times and with just five subjects it's virtually impossible to draw any conclusions. A human PET study with n=5 would never get published; by the standards of chimp research n=5 is big because chimps are much harder to work with. Personally, I'm just glad I don't work with chimps.

What about Life, the Universe, and Everything? Well, the "Are Faces Special" debate is relevant to such cosmic questions (almost), because it's one aspect of the great "modularity" debate, which is basically psychologists and neuroscientists debating the existence of human nature. If humans are genetically programmed to have a part of the brain (a "module") specialized for processing faces, presumably this is because we evolved to do so. If so, then this makes it very plausible that other parts of our brains evolved for such specialist purposes, and this implies that our minds work in certain ways because of evolution (i.e Evolutionary Psychology) and that human nature is largely fixed.

On the other hand, if faces aren't special, maybe nothing is - maybe there is no such thing as human nature and all our behavior is learned by experience. That would imply that culture and history are much more important than biology in understanding human life, and that with sufficient political and social advancement anything is possible! Wow. That's the importance of neuroscience. At least, that's what neuroscientists will tell you when they want you to give them money or buy their books...

(*) If you're at a cognitive neuroscience conference and feel like a slap in the face, try opening a conversation with a pretty young grad student with the line "I don't know if faces are special, babe, but yours is".
(**) Although given the state of some undergrads, the differences might not always be in the human's favor.

L PARR, E HECHT, S BARKS, T PREUSS, J VOTAW (2008). Face Processing in the Chimpanzee Brain Current Biology DOI: 10.1016/j.cub.2008.11.048