Category Archives: bad science

Reading and the brain, and “brain scans”

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There’s a new book out about what happens in our brains when we read, which may appeal to people interested in accessible accounts of neuroscience, as well as to those of us who are watching the shift from paper to electronic reading.

Reading in the brain : the science and evolution of a human invention
Stanislas Dehaene. (New York : Viking, 2009)
ISBN: 9780670021109 – Description: xi, 388 p. : ill., map ; 24 cm.

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I put a reserve on it at the library and am waiting for it to arrive. In the meantime, I found that the author has put all the color figures online along with short chapter summaries. The imbalance on the webpage between text, and the diagrams and brain maps, makes the book look more forbiddingly technical than it is, I hope. Unfortunately the book on Amazon doesn’t have the LookInside feature, so we can’t look at more of the text. Reviews have been mostly positive (links to several, on author’s page; Barnes and Noble review) though one was critical of the book’s accessibility for us “interested lay readers”:

Unfortunately, he needs to lay a lot of groundwork. This makes the first 100 pages of the book an excruciating slog. While it picks up after the first two chapters, the book still sometimes slips back into detailed explanations of neurophysiology. Dehaene is first and foremost an academic, and he seems to want to make his work defensible to his peers even as he tries to explain it to laymen. This is especially problematic in his diagrams. Rather than helping to clarify points, his visual presentations are almost always overly technical, presenting formulas and pictures of the brain that are difficult to decipher. Part of the problem is that images are all black-and-white. While he offers up full color versions on the book’s website, that’s only useful to readers who are also regularly consulting their computers. …The result is a work that requires focus to read, but rewards the effort.

It is disappointing that, according to this reviewer, the images in the book are not in color like those on the web. This reminds me of a book I looked at recently on the various branches of our early human-ish ancestors, in which maps to locate the various hominid species were poorly done or not there at all. Publishers try to cut corners and end up crippling the book. But I hope that won’t be the case here, and even if parts of it are over my head I look forward to the exploration.

I’m expecting a stimulating mix of actual established neuroscience, conclusions based on new research still open to interpretation, and informed speculation. After discussing how, he believes, reading (including our writing systems) developed in response to our neurological structures—“over time, scribes developed increasingly efficient notations that fitted the organization of our brains”, Dehaene applies the same theory to other areas of human culture: “Mathematics, art, and religion may also be construed as constrained devices, adjusted to our primate brains by millennia of cultural evolution.”

Cautions about fMRI (brain scan) studies: What a fish can tell us

I don’t know how much of Reading in the Brain relies on fMRI data, but many of the popularized “this-is-how-your-brain-works” revelations do rely heavily on brain scans, including fMRI, and we’re seeing some push-back from other scientists. A study at Dartmouth (reported by Wired, and Science News) found that a salmon’s brain had “a beautiful, red-hot area of activity that lit up during emotional scenes [photos put before the salmon’s eyes]”. Wow! Unfortunately for all but the spiritualists among us, the fish in question was dead. Apparently the neural activity that showed up was random, and more rigorous statistical analysis of the data revealed this. While many popularizers, especially in the general media, give the impression that brain scan interpretation is cut and dried, the truth is quite the opposite.

Less dramatic studies have also called attention to flawed statistical methods in fMRI studies. Some such methods, in fact, practically guarantee that researchers will seem to find exactly what they’re looking for in the tangle of fMRI data. Other new research raises questions about one of the most basic assumptions of fMRI — that blood flow is a sign of increased neural activity. At least in some situations, the link between blood flow and nerve action appears to be absent. Still other papers point out insufficient attention to insidious pitfalls in interpreting the complex enigmatic relationship between an active brain region and an emotion or task. (Science News)

Michael Shermer, founding Publisher of Skeptic magazine and columnist for Scientific American, gives an excellent presentation of how fMRI works and why “bright spots” in the brain don’t necessarily tell us much of anything. His article (pdf) , “Five Ways Brain Scans Mislead Us”, is as technical as it needs to be but won’t give you a headache. A more technical but still readable article by Edward Vul et al., “Puzzlingly High Correlations in fMRI Studies of Emotion, Personality, and Social Cognition” examines one major source of errors in brain scan analyses. [There’s a short summary here at mindhacks.com, if you want to skip the technical details, and an interview with Edward Vul at scientificamerican.com.]

So while the area known as “social cognitive neuroscience” is fascinating, and we all love quick and easy explanations, remember that much of what you read in this area is, like the lottery, best used “for entertainment purposes only”.

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Bad Science: Housework helps combat anxiety and depression

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I’m a subscriber to New Scientist, the British weekly magazine of science news for the rest of us. I subscribed to Science for a while too, because it publishes researchers’ actual articles, but decided I’d rather have more numerous reports with less math. New Scientist contains short reports and a few longer articles as well as interviews, and a great feature at the end where people write in requesting explanations for odd observations (very British, I think, in the tradition of the journal Notes and Queries (1849 – present), or letters to the London Times from country parsons reporting the first sighting of a bird).

Anyway, though I still find NS interesting and valuable, I’ve begun to feel they are sometimes sacrificing science for snappy headlines. Here’s an example that is from a while ago, but quite illustrative.

Housework helps combat anxiety and depression

FEELING down? You might be able to dust away your distress. Just 20 minutes a week with the vacuum cleaner or mop is enough to help banish those blues, and sport works even better.
That’s the message from Mark Hamer and his colleagues at University College London, who wanted to find out what benefits arise from different types of physical activity. They examined data from questionnaires filled in by almost 20,000 Scottish people as part of the Scottish Health Surveys, carried out every few years. Some 3200 respondents reported suffering from anxiety or depression, but those who regularly wielded the mop or the tennis racket were least likely to suffer, the researchers report (British Journal of Sports Medicine, DOI: 10.1136/bjsm.2008.046243).

One 20-minute session of housework or walking reduced the risk of depression by up to 20 per cent. A sporting session worked better, reducing risk by a third or more. Failing housework or sport, says Hamer, try to find something physical to do. “Something – even for just 20 minutes a week – is better than nothing.”

––From issue 2652 of New Scientist magazine, 19 April 2008, page 4-5. Abstract of original available free, entire article requires fee to BJSM.

Why we shouldn’t believe this

In New Scientist’s brief bit, there’s absolutely no evidence for a causal relationship between exercising and being less depressed. It’s an example of the frequent, but quite false, assumption that because two things are associated, one causes the other. Other relationships are quite possible. Does physical activity really reduce depression and anxiety, or are the people who actually do housework or sports simply the ones who have less severe symptoms to start with? Or is there some other connexion altogether? Nothing in the New Scientist, or the article abstract, addresses that question. But it makes an eye-catching headline, to say that housework cures depression.

To investigate the question scientifically, it is necessary to take a large number of depressed people and randomly assign them to one of three groups: an exercise group, a control group given some other task like filling in a weekly questionnaire or reading about depression, and a third group who don’t get any new activity or other attention from the researchers. (Ideally those doing the testing and analysis don’t know which group is which.) Then, at the beginning and end of the study, measure psychological state using some accepted reliable tests and see what changes. Finally, use statistical analysis to see if the changes are significant or might be due to chance. [Even after that, other factors may make the apparent conclusions false: maybe the exercise was not enough to have an effect, or during the study the country went to war and everybody stayed depressed, or the social aspects of being in an exercise group had more effect than the actual jumping and sweating did.]

No doubt such a study has been done, probably more than once; advising depressed people to get more exercise is a standard approach and insurance companies would love to fund the research to support it. Mark Hamer might have cited previous work in the full text of his article in the British Journal of Sports Medicine (which New Scientist should have read before writing their brief and provocative piece) but we readers have no way of knowing this.

In this particular case––the effect of exercise on individuals––researchers would have to be vigilant about the distortion of results due to participants dropping out or failing to comply with the activity levels. Even the method of choosing participants can affect reliability of results: if the depressed people are chosen from those who show up at clinics, their symptoms may be overall less severe than the symptoms of people too depressed even to go to a clinic.

A similar example: exercise and fibromyalgia

I have fibromyalgia, and some researchers have pronounced aerobic exercise to be beneficial for reducing the symptoms of this condition’s chronic pain and fatigue. Exercise is fundamentally a good thing, I agree. It distracts one from symptoms, adds an interest, may confer a feeling of control over one’s illness, strengthens muscles, promotes growth of new neurons in the brain, and can improve flexibility.

But. In moderate to severe cases of fibromyalgia, even mild exertion can cause greatly increased pain and exhaustion. Unlike the familiar “weekend athlete” reaction, the increased pain and fatigue may last a week or several weeks. This means that for some individuals the goal of walking briskly for a few blocks could take years to attain, since we are knocked back to the starting point when we overdo, or when something else in our lives like a cold or interrupted sleep aggravates our symptoms.

Some time ago I read a review article which gathered the results of a number of studies on exercise and fibromyalgia, and I noted that in some the dropout rate was high but wasn’t mentioned in interpreting the data. And then there are people, like myself, who would never enroll in an aerobic exercise program because we’ve “been there, done that” and it was painful and unproductive. If we’re not counted, and a high dropout rate is glossed over, then to whom do the results apply?

What can we say about exercise, then?

I am skeptical of the efficacy of exercise as a general one-size-fits-all prescription for fibromyalgia or depression. I would suggest the fibromyalgia studies really show that exercise appears to be helpful for those people able to endure it, but, while all patients should be encouraged to do appropriate activities as tolerated, there’s a need to be gradual and cautious. Some patients may never be able to attain exercise levels that make appreciable improvements to their symptoms, despite sincere efforts. (This doesn’t mean that exercise is without benefits to them, though. My level of physical activity doesn’t seem to help my pain, fatigue, or quality of sleep, but I’m much happier when I get out for a walk or a bit of gardening.) At an education class on fibromyalgia, I heard someone ask “How can I exercise when even walking around the house is too strenuous?” The reply was, “Can you get up and walk all the way around your kitchen table? Good. Start with that and work up.” Sensible advice, but actual improvement in symptoms may be a very long time in coming for that person.

For depressed people, exercise is unlikely to be harmful and may indeed help––I myself believe that it does––but there’s no evidence of that in the New Scientist account of Mark Hamer’s work.

I felt this was worth writing about for two reasons, one general and one particular. It’s a good example of how the media gives us accounts of scientific research without the details needed to evaluate them. And, invisible conditions like fibromyalgia and depression are different from most other health problems. They are regarded by many as non-ailments or personal weakness/malingering, so it is easy for “exercise may help” to become “quit complaining, pull up your socks and get on with it”. From there it’s a short step to “all these patients could feel better but they just won’t do the work necessary; they cling to their disease.”

And I have to admit that the example used, housework, was particularly galling to me. While there are people who can enjoy housework as a zen activity, or feel great satisfaction at making their floors and sinks shine, most of us (male or female) do not get much pleasure at all from it. Every time you do it, next day there it is again, dirty dishes, laundry piling up, dog hair floating across the floor. Truly, housework is never done. And, given that housework is still seen more as a woman’s responsibility than a man’s, and that women have a higher rate of depression than men, the “FEELING down? You might be able to dust away your distress” line seems offensively sexist and dismissive.

Contagious happiness?

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Are we so hungry for meaning in our chaotic world, that mere association is automatically assumed to be proof of a cause and effect relationship? Again and again, the media seizes upon research results (sometimes with the eager cooperation of the researchers) and touts them as proof that A causes B.

Latest in this parade of dubious connexions is the study which found that happy people tend to know a lot of other happy people, and the more happy people in your circles of acquaintance, the happier you are. Ergo, knowing happy people makes you happier!

An article about the study says:

The scientists found that a person’s happiness is most likely to boost the happiness levels in people closest to him — spouses, relatives, neighbors, and friends.

But, if one person is happy, that increases the chances of happiness in a friend living within a mile by 25 percent. The “cascade” effect, as the researchers put it, continues: a friend of the friend has almost a 10 percent higher likelihood of being happy, and a friend of that friend has a 5.6 percent increased chance.

In the other words, one person’s happiness can spread outward through three degrees of separation. Those at the center of such circles may be people that “you have never met. But their mood can have a profound effect on your own mood,” Fowler said.

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Fig 1 Happiness clusters in the Framingham social network. Graphs show largest component of friends, spouses, and siblings at exam 6 (centred on year 1996, showing 1181 individuals) and exam 7 (year 2000, showing 1020 individuals). Each node represents one person (circles are female, squares are male). Lines between nodes indicate relationship (black for siblings, red for friends and spouses). Node colour denotes mean happiness of ego [individual being studied] and all directly connected (distance 1) alters [alters are persons connected to the ego, potentially influencing the behaviour of the ego], with blue shades indicating least happy and yellow shades indicating most happy (shades of green are intermediate).

Figure (reduced here) and caption are from the full article, in the British Medical Journal.

The original article’s abstract says in part,

Results Clusters of happy and unhappy people are visible in the network, and the relationship between people’s happiness extends up to three degrees of separation (for example, to the friends of one’s friends’ friends). People who are surrounded by many happy people and those who are central in the network are more likely to become happy in the future. Longitudinal statistical models suggest that clusters of happiness result from the spread of happiness and not just a tendency for people to associate with similar individuals. A friend who lives within a mile (about 1.6 km) and who becomes happy increases the probability that a person is happy by 25% (95% confidence interval 1% to 57%). Similar effects are seen in coresident spouses (8%, 0.2% to 16%), siblings who live within a mile (14%, 1% to 28%), and next door neighbours (34%, 7% to 70%). Effects are not seen between coworkers. The effect decays with time and with geographical separation.

Conclusions People’s happiness depends on the happiness of others with whom they are connected. This provides further justification for seeing happiness, like health, as a collective phenomenon.

So that’s clear: happiness is somehow “contagious”! By this line of reasoning, we could investigate the contagious effects of race, profession, sports fanaticism, and most anything else. I must have become white (and stayed that way) because nearly all my friends are white; a lawyer is a lawyer because he or she knows so many lawyers, and so on.

On a certain level, I have no argument with the direct “contagiousness” of positive emotion: it certainly cheers one up to be around smiling ebullient people. I still remember a dark rainy day, decades ago, when I was walking gloomily across my college campus and passed someone smiling and carrying a bright bouquet of flowers. It actually did change my mood, I smiled back and was bumped out of my self-absorbed thoughts. But then, the same effect might well have resulted from other stimuli that are enjoyable to me: seeing a horse running in a field, reading something that introduced a new idea, even coming in out of the rain into a warm inviting place. And if I do things often enough that elevate my mood, I will probably be in fact be happier than if I do the opposite: but these are choices, not influences beyond my control.

When it comes to a person’s close associates, surely Pollyanna chooses to hang around mostly with other cheerful folks, rather than letting Cassandra or Gloomy Gus bring her down. Perhaps really unhappy people are hard to be around and don’t share the interests and types of conversations that are common to happy people. Some people have truly terrible experiences dealt them by fate, and are unhappy; with others you feel like a good kick in the pants to get them out of being so self-centered would go along way toward changing their mood; either way, it seems entirely reasonable that the positive happy busy people tend to associate more with others of their own “type”. What was that result of an ancient sociological study? Oh yes: “Birds of a feather flock together”. The data has been lost but the conclusion has survived.

Some of the dots on the graph are family, who may be viewed as unchosen associates. Or are they? Do we know if the researchers counted that grumpy cousin I don’t like and never see (though she lives only five miles away)? And other studies have shown that there are genetic factors influencing traits such as agreeableness and extroversion which may be associated with degree of happiness. So, if happy people tend to have happy sibs and cousins, this could be caused more by shared genetically-influenced traits than by their “contagious” influence on one another.

And, in a long-term study of human behavior like this one (twenty years), some less happy people who are around happier people may indeed benefit from the activities, the “vibes”, may even learn better behavior or learn how to fake it…but those who don’t will tend to drop away from the setting where they feel out of place. Or won’t be invited so often because they “just don’t seem to enjoy our dinners or outings”. So over time people settle out into groups they feel comfortable with. This can’t be really big news. Animal-study researchers don’t count many fervid PETA members among their circles of friends and close acquaintances, and vice versa. There’s a cause and effect here all right but it may not be the one being alleged in this study.

I should admit the obvious, that I don’t understand regression analysis and the other statistical tools that are used to verify the significance of associations in studies like this one. However, I don’t think it matters. We’re not talking about whether the associations exist, but about what they mean.

This is, of course, the weakness with observational studies as opposed to experimental ones. All the observer can say is what was observed; cause and effect relationships are speculative in all but the simplest of situations (dropping things off a tower, for example: Yes! they fall because they were dropped!). In this case, an experimental study might try to find a way to cause happy and unhappy people to hang around together for months or years and see what the results are. But how can this be done without denying people freedom of association, which is a factor in happiness? We could pay them to gather together, but what about those for whom no money is enough to make tolerable the company of such damnably cheerful/such oppressively dismal folks? Individuals have even been known to change jobs because they couldn’t stand the people they worked with.

Figuring out complicated things just can’t be as easy as the media, and perhaps some scientists, would wish. And in this discussion, we haven’t even gotten to evaluating the definition of “happiness”!