Category Archives: mind & brain

Cheetah or armadillo? Check your reaction speed

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You may not like the results, but here’s a quick test of your eye-hand response speed. It’s a little game on the BBC’s site, part of their section on the human body. This part is about sleep, because being tired increases reaction time. Your job is to use a dart gun when sheep at one side of the screen

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make a run for the other side. The dart gun will stop them in their tracks.

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Don’t get an itchy trigger finger, though, because a false move costs you 3 seconds of time in which sheep can run across with impunity. At the end—5 sheep—you’ll get a rating, and a list of your exact times to the thousandth of a second.

These are the fastest sheep I ever saw, and my rating never rose above Ambling Armadillo. Use the link above rather than the one on the BBC’s main Sleep page, because that one goes to a small screen version which gives you even less time to nail those pesky sheep.

Too bad the BBC isn’t using this as an opportunity to collect data; if we all gave our age and sex, they’d have a big sample for correlating those factors with reaction time. How long the time is, depends on mental processing speed; it’s in your brain, not your muscles (although while darting sheep I found that my index finger clicked my laptop trackpad button faster than my thumb, which is usually what I click with in normal computing). Some of the brain-game sellers say their games improve reaction time, and that seems quite believable; athletes practice to increase their reaction speed, and pianists get faster with practice. I’d be interested in knowing how much of the improvement from computer brain games is transferable to non-game situations, though. And naturally the fastest reaction times occur when there is only one action to be chosen: you’re going to be faster using the dart gun against the sheep, than responding to a complex driving emergency where you must decide whether to swerve or brake, how much, and how fast.

Reaction times become longer with age (after the late 20’s, according to this literature review on reaction times), fatigue, distraction, and a variety of other factors. And, when times are measured in thousandths of a second, a single individual will exhibit quite a bit of variation even in a single testing session. The literature review cited was done in 2008 and seems to be a good summary of what’s known.

Looking for more about reaction times, I found another online test which doesn’t have any cute sheep but does track and display the data from all users. It’s not broken down by age or sex, though. The site’s owner says that, based on 2,656,058 clicks recorded thus far, the average (median) reaction time is 215 milliseconds. But some people can regularly post times of 130ms. This test not only rejects clicks that jump the gun (before the signal is given), it only counts data of 100ms and above, in order to avoid skewing the data with “lucky clicks”, when someone’s brain issues an order to click before seeing the signal but then the signal occurs just before their finger performs the movement.

Let us marvel for a moment at the process, which involves multiple neurons structured like this.

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Diagram from Wikipedia, where a larger version can be seen.

Communication within a single neuron is electrical, but that between neurons is chemical, so neuron A has to make and release a chemical to pass a message on to other neurons.

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A signal propagating down an axon to the cell body and dendrites of the next cell. (Wikipedia)

And this is just the transmission part of reaction time. The processes involved in choosing an action…well, my neurons are boggled enough for one day.

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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If Babbage HAD built his “Difference Engine”

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Here’s a funny comics-version, from 2D goggles. Actually it is about mathematician Ada Byron Lovelace (1815 – 1852), but we all know that women never get top billing!

The comic was made for “Ada Lovelace Day”, to promote a film (to be offered to local stations by PBS) about this remarkable woman, and the film-makers need our help:

letters of support from people who have been influenced in some way by Ada and who are willing to help publicise the film, be a part of the interactive website, perhaps show the film, or contribute in any other way.

Rosemarie says, “I need letters from people stating how important a film like Ada is and how they through their networks can help to publicize the film. It would be great if the women have organizations they work or belong to. If they are software developers or computer experts, this would be great. It would be best if they were Americans, as the NSF (National Science Foundation) is American.”

If you’re not American, letters would still be useful of course! The deadline is the end of October.

Please write to:

Rosemarie Reed
On the Road Productions International, Inc.
310 Greenwich Street, 21F
New York, NY 10013
Or email Rosemarie directly, rreed40148@aol.com.

After some thought, I decided to write a letter based on my experiences giving books to kids at the food pantry, and the unabated gender gap I see in kids’ interest in science and math. Sure, the older kids are computer users, but computers are fun personal devices; they still display an aversion to math and science, especially the non-biological sciences. A few boys get drawn in by technology, but I don’t see it in girls. [I have a small sample size, I admit, and it is a rural area.]

Who was Ada Lovelace?

Ada Byron Lovelace was the daughter of Lord Byron (his only legitimate child); she married a nobleman, and was part of the social whirl of that class, dancing and entertaining. [Photo below from Wikipedia]

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Wikipedia tells us that

During a nine-month period in 1842-43, Lovelace translated Italian mathematician Luigi Menabrea’s memoir on Babbage’s newest proposed machine, the Analytical Engine. With the article, she appended a set of notes. The notes are longer than the memoir itself and include (Section G), in complete detail, a method for calculating a sequence of Bernoulli numbers with the Engine, which would have run correctly had the Analytical Engine ever been built. Based on this work, Lovelace is now widely credited with being the first computer programmer and her method is recognised as the world’s first computer program.
However, biographers debate the extent of her original contributions. Dorothy Stein, author of Ada: A Life and a Legacy, contends that the programs were mostly written by Babbage himself. Babbage wrote the following on the subject, in his Passages from the Life of a Philosopher (1846):

I then suggested that she add some notes to Menabrea’s memoir, an idea which was immediately adopted. We discussed together the various illustrations that might be introduced: I suggested several but the selection was entirely her own. So also was the algebraic working out of the different problems, except, indeed, that relating to the numbers of Bernoulli, which I had offered to do to save Lady Lovelace the trouble. This she sent back to me for an amendment, having detected a grave mistake which I had made in the process.

The level of impact of Lovelace on Babbage’s engines is difficult to resolve due to Babbage’s tendency not to acknowledge (either orally or in writing) the influence of other people in his work. However, Lovelace was certainly one of the few people who fully understood Babbage’s ideas and created a program for the Analytical Engine, indeed there are numerous clues that she might also have suggested the usage of punched cards for Babbage’s second machine since her notes in Menabrea’s memoir suggest she deeply understood the Jaquard’s Loom as well as the Analytical Engine. Her prose also acknowledged some possibilities of the machine which Babbage never published, such as speculation that “the engine might compose elaborate and scientific pieces of music of any degree of complexity or extent”.

The Difference Engine becomes reality after 150 years

Babbage never built his mechanical computer, but the London Science Museum did make a working version. It was finished in 1991 for the 200th anniversary of Babbage’s birth.

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A view of “some of the number wheels and the sector gears between columns”

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Difference Engine model photos source.

Ada Lovelace, “The Right Honourable the Countess of Lovelace”, gave birth to three children (the firstborn was named Byron), and died at 37 of uterine cancer and being bled by her doctors.

Let’s support that film, with letters or emails to demonstrate demand for stations to show it! Here’s the email again, rreed40148@aol.com.

More about girls being turned off to math and science

Feminist Chemists cites a 2008 study by the American Mathematical Society:

In elementary school, girls do as well as or better in math than boys. In middle school, girls with an inclination for math begin to lose interest and fall behind, mostly due to peer pressure and societal expectations. Throughout middle and high school, social stigma and lack of appropriately challenging educational opportunities for the mathematically precocious becomes a hard reality in most American schools. Consequently, gifted girls, even more so than boys, often camouflage their mathematical talent to fit in well with their peers.

A study published in June by the National Academy of Sciences found

“It’s not an innate difference in math ability between males and females,” says Janet Mertz, a UW-Madison professor of oncology and one of the authors of the article that analyzes and summarizes recent data on math performance at all levels in the United States and internationally. “There are countries where the gender disparity in math performance doesn’t exist at either the average or gifted level. These tend to be the same countries that have the greatest gender equality.”

Gender bias and expectations are not the only thing we have to worry about. It’s not just girls––boys are losing interest too, according to the AMS research:

”The U.S. culture that is discouraging girls is also discouraging boys,” says Janet Mertz, a University of Wisconsin-Madison professor of oncology and the senior author of the study. “The situation is becoming urgent. The data show that a majority of the top young mathematicians in this country were not born here.”

[NOTE: While Janet Mertz was one of the authors on each study, the PNAS and AMS studies are two different projects. The latter, published Oct. 10 in the Notices of the American Mathematical Society, was a comprehensive analysis of decades of data on students identified as having profound ability in math (Science News Oct. 13, 2008). The other study was published June 1, 2009 in the Proceedings of the National Academy. It looked at US and international data on students of all levels of ability, to answer three key questions: “Do gender differences in math performance exist in the general population? Do gender differences exist among the mathematically talented? Do females exist who possess profound mathematical talent? The answers, according to the Wisconsin researchers, are no, no and yes.” (Science News June 2, 2009).

You may remember the remarks of Lawrence Summers in 2005 (he was then President of Harvard, and is now an economic adviser to President Obama), to the effect that innate differences between men and women might be one reason fewer women succeed in science and math careers. These two studies would support the conclusion that if innate differences do influence women’s lack of success in these fields, the differences are not in mathematical ability. Maybe we should look at “innate differences” in aggressiveness and willingness to withstand unduly competitive or even hostile treatment from colleagues and superiors. Or at insecurity and discomfort, innate or not, which arise in male academics and administrators when females display ability, competence, and promise. A few decades ago women rarely appeared in symphony orchestras unless they played the harp; auditions behind screens changed that! Did our musical ability transform itself overnight? Probably not. ]

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[Photo from another good article on the AMS study]

Send an email for Ada and our kids, and consider how you yourself might interact with kids about math and science. Take a trip to the Science Museum if you are fortunate enough to live near one, read a book together, in general don’t act as if math and science are boring geek fare. Even if a lot of it is beyond you, as higher math seems to be beyond me, that doesn’t have to be true for the kids you know. Since I was in college, math has become much more important in biological sciences, ecology, even social sciences like history, so if I were a history major today I would probably need to take at least an introductory statistics class.

We all need to model a respect and interest for learning, to the kids around us. Kids start out as voracious learners: have you tried to learn another language lately? Hard, right? Babies do it, and young kids pick up second languages easily. They’re always learning, not just skills and processes but attitudes too, so let’s not convey bad attitudes about learning, reading, thinking!

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.