Archive for March, 2010

Mar 31 2010

Magnets and Morality

Published by under Neuroscience

MIT researchers have published a paper in which they use transcranial magnetic stimulation to alter, or bias, the moral judgments made by test subjects. Many people have e-mailed me this story with the comment that it seems fishy to them. Using magnets and changing morality so simply triggered their skeptical detectors, which is reasonable. But in this case the research seems perfectly legitimate, although some of the reporting has been superficial or dubious.

TMS

The whole notion of using magnets as a biological or medical intervention has long been exploited by the dubious magnetic therapy industry. I do agree that there are many fraudulent or quacky magnetic devices out there with unscientific claims. I do not recommend that people buy magnetic insoles for their shoes or strap refrigerator magnets to their joints to relieve pain or promote healing.

However, transcranial magnetic stimulation (TMS) is different. The brain is an exquisitely electrical organ, allowing for electromagnetic interventions to its function. We have recently developed the technology to use strong magnetic fields, precisely tuned and focused, to either stimulate or inhibit the electrical activity in brain tissue.

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Mar 30 2010

How to Train Your Dragon – With a Scottish Accent

Published by under Skepticism

This may be my first actual movie review, but there were a few points I thought worth musing about after watching the new Dreamworks movie – How to Train Your Dragon. I promise – no real spoilers.

First, let me say I really enjoyed the movie. It was much better than I thought it was going to be. My favorite aspect of the movie is the fact that the nerd is the hero. Basically this is the story of a nerd who feels out of place in a town of jocks – a town that celebrates jocks and completely rejects his quirky nerditude. Eventually the protagonist finds a way to use his smarts and curiosity to beat the jocks at their own game – and even to change the very nature of the game, making it one that celebrates smarts over brawn.

I have nothing against jocks or athletic prowess, in fact I think excellence in the physical realm is worth celebrating and I have enthusiastically engaged in sports my entire life. This is not really a “revenge of the nerds” type plot line, but rather seeing the value in recognizing a diversity of talents, rather than narrowly defining success. Nothing new, really, but nicely done.

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Mar 29 2010

A New Human Species?

Published by under Evolution

First there were several species of humans, at least from the perspective of some Western naturalists who considered Africans a separate species. But it soon became apparent to biologists that all people of the earth are one species. Darwin raised the possibility that we evolved from other species, and this was apparently confirmed with the discovery of Neanderthal man. It turns out Neanderthals are our cousins, not our ancestors, but with them there have been at least two species that can be called “human” on this planet.

And that was the status of things for a while. Homo erectus and Homo habilis extended the number of species in our genus (it’s debatable whether habilis should really be an Australopithecus), but they are not close enough to us to be considered human cousins. More recently several species have been identified at the root of humans and neanderthals. Homo heidelbergensis is probably our direct ancestor from about 650,000 years ago. But there is also Homo antecessor, which (along with heidelbergensis) likely evolved from Homo ergaster in Africa.

Then a third recent close human cousin was discovered – Homo floresiensis, or the Hobbit. This is still controversial, but the data is leaning in the direction of concluding that a diminutive species of human lived until about 12,000 years ago on the island of Flores. We missed by a geological hair’s breath there being as many as three distinct human species occupying the earth. Given the problems we have had with race relations, I have often wondered how our society would deal with an actual distinct species.

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Mar 26 2010

Neural Stem Cells and Plasticity

Published by under Neuroscience

New research is expanding our knowledge of the nature of plasticity in the brain, creating the potential to treat a variety of neurological diseases and injury with transplanted stem cells.

At present the research is mostly in the proof of concept stage – doing animal studies to understand plasticity and the fate and function of neural stem cells. Plasticity is the ability of the brain to form new connections and pathways, even to change the pattern of its hardwiring. Plasticity is maximal when we are developing, and progressively declines with age. Although, even adults retain some plasticity and this likely results from the presence of neural stem cells (young cells capable of developing into new neurons) present even in the adult brain.

Further, all brain regions have a window of intense plasticity during which they are forming the majority of their connections. This development is closely tied to use, and if the brain is deprived of the appropriate sensory input or stimulation during this critical window of development, permanent deficits will develop. For examples, if children are not exposed to language by the age of 4 or so, their language window will close and they will never fully develop their language cortex. Or, if one eye is patched in young children, during the critical window in which binocular vision develops, they will never develop binocular vision.

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Mar 25 2010

The Flake Equation

XKCD, a science-savvy webcomic, has a recent installment called The Flake Equation (a play on the Drake Equation which provides the formula for calculating the likely number of technological civilizations in the universe). I am now going to take his brief and elegant point and beat that horse to death.

While XKCD applies his equation to UFO sightings, it applies equally well to any paranormal or pseudoscientific phenomenon – bigfoot, ghosts, alternative medicine healings, etc. Often we are told by believers that “where there is smoke there is fire.” In other words – with so many people reporting sightings or healings, there must be something going on.

Skeptics, of course, recognize this as a fallacy. There is a major unstated premise or assumption in this position. We must ask ourselves – in a hypothetical world in which we are not and have never been visited by aliens, what would we expect in terms of sightings and experiences? Is such a world compatible with the current number and quality of sightings? I think the answer to this is a pretty clear “yes” – and that is exactly the point that XKCD is making.

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Mar 23 2010

The Global Workspace – Consciousness Explained?

Published by under Neuroscience

As neuroscientists continue to build a more accurate and sophisticated model of the human brain, finding the neurological correlate of conscious awareness remains a tough nut to crack. The difficulty stems partly from the fact that consciousness is likely not localized in any one specific brain region.

But as our technology advances and we are able to look at brain function in real time and in greater detail, researchers are starting to zero in on the hardwiring that produces consciousness.

In this context, consciousness is operationally defined as being aware of sensory stimulation, as opposed to just being awake. We are not conscious of everything we see and hear, nor of all of the information processing occurring in our own brains. We are aware of only a small subset of input and processing, which is woven together into a continuous and seamless narrative that we experience.

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Mar 22 2010

Hyperactive Agency Detection

Something does not seem quite right. The most powerful man in the world, John F. Kennedy, was taken out by a lone nutjob of no previous consequence? A jet flies into the pentagon and yet the expected debris is not visible. And why can’t I see stars in the NASA Apollo moon landing photos?

Some hidden agent must be at work, conspiring to deceive and carry out some sinister plot.

At least that is how our brains are hardwired to think, and some of us more than others. This tendency has been termed the “hyperactive (or hypersensitive) agency detection device” -  HADD – coined by Justin Barrett. Understanding that HADD is an intrinsic part of human nature is part of the core knowledge base of the skeptic.

As a neurologist and a skeptic I am particularly interested in how brain function relates to human intellectual strengths and weaknesses and how knowledge of such helps us to avoid common mental pitfalls. In other words, knowledge of how the human brain works helps us think better – to be more skeptical and avoid error.

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Mar 19 2010

Statistics in Science

Published by under General Science

Tom Siegfried wrote an article on the use of statistics in science that is simultaneously excellent and frustrating. It is an excellent review of common errors in using and thinking about statistics in science. But it is frustrating because Siegfried frames his article as a problem with “science” – as if his criticisms are criticisms of science itself, rather than the failings of individuals. At times he also writes as if the problems with statistics that he points out are fatal flaws or “some” researchers are just now starting to take into consideration.

Rather, from my perspective statistics are a very complex and challenging field. Most scientists I know have a moderately sophisticated understanding of statistics, many know far more of statistics than I, although some apparently less. However, most large studies consult with statisticians who are experts in statistical analysis. The primary difficulty is with interpreting studies once they are published (even when the paper itself gets the statistics correct).

But the specific problems Siegfried points out have been widely known for years, and those researchers with a better understanding of statistics have been taking them into account for as long as I can remember. Most of them I learned about in medical school at the hands of researchers and experts in public health.

But all that aside – Siegfried does provide an excellent review of common mistakes interpreting statistics in research, especially medical research. The article is worth a thorough read, but I will give some highlights.

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Mar 18 2010

Homeopath Benneth Jumps the Shark

You may recall I recently discussed the incoherent rant of homeopath John Benneth, attacking defenders of science-based medicine. His tactic was clear – rather than discussing the scientific evidence, he chose to launch a personal attack against those who have the audacity to disagree with him.

This kind of behavior seems to becoming more common as the defenders of nonsense are being called out in public. Most recently an exhaustive review of the evidence for homeopathy led the UK Science and Technology Committee to conclude that homeopathy should not work, it does not work, and all public support for homeopathy and homeopathy research should be halted.

The simple fact is that homeopathic remedies are not remedies at all. They are nothing but water, with (in most cases) any active ingredients diluted to such a degree that nothing but water remains. Further, clinical studies, when viewed in total and not cherry picked, show that homeopathy (not surprisingly) does not work. The underlying principles of homeopathy, such as like cures like, is nothing but magical superstition.

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Mar 17 2010

Eye Evolution and Irreducible Complexity

Published by under Evolution,Skepticism

A creationist commenter on a post of mine discussing lame creationist arguments first admitted that he did not actually read my post, and then began to repeat the same tired creationists lies and logical fallacies we hear over and over again.

I had asserted a well-established biological fact – the eye is not irreducibly complex. There are examples in nature of simpler eyes that represent probable stages through which the vertebrate eye evolved. I made this as part of a broader point, that many structures and systems claimed to be irreducible have known simpler antecedents, and I even provided a link to a page on Talk Origins that linked in turn to many articles with the evidence for this claim.

Creationists, however, are apparently not interested in making sound arguments or what science actually has to say about any particular question – only obfuscating the truth with misdirection and debating tactics. The commenter claimed I had not bothered to provide evidence to back up my claim, and inferred that I therefore could not.

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