Archive for June, 2011

Jun 09 2011

The Genetics of Autism

Published by under autism,Neuroscience

The recent issue of Neuron has a series of articles providing more information about the genetics of autism spectrum disorder (ASD). ASD is characterized by decreased social ability as a core feature, with other clinical features being variable. It is also not a single disease or disorder, and not just because of the spectrum of clinical features. Like many clinical entities, there can be many underlying causes that result is similar-looking clinical effects.

While debate rages as to possible environmental triggers or even causes of ASD, researchers have been slowly building a picture of ASD as a complex genetic syndrome. Literally hundreds of genes have been potentially implicated. Many of the genes linked to ASD are involved with brain proteins or brain organization.

The recent studies in Neuron look specifically at families with a single child with ASD. In families with multiple children, or with a parent and child on the spectrum, the disorder is likely inherited. But what of families with only one child with ASD, and at least one child without, with no affected parent? Such a pattern can also be consistent with an inherited disorder, if it is recessive or X-linked. In a recessive disorder both parents can be unaffected carriers, and 25% of children will be affected – so having a single affected child is not unusual. However, ASD genes tend to be dominant, which means at least one parent should be affected along with at least 50% of children.

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Jun 07 2011

Language and Thinking

Published by under Neuroscience

It has been known for many years that language has a profound effect on the way we think. Words and syntax not only give form to our thoughts – they constrain and influence them. Words are anchors for ideas, and as we expand our vocabulary, we expand our intellectual repertoire.

The extent of this effect, however, is still a matter of debate and research. Does the syntax of language, for example, influence our thinking in other domains, such as math, music, or visuo-spatial reasoning? A new study suggests that various types of abstraction are linked in the brain, perhaps they are even variations on a theme.

The study in question looked at a process called priming. In psychological studies, if subjects are made to think in a certain way, that will prime them to think in a similar way on a later task. With respect to language, if subjects use a certain syntax, they are more likely to use it again when asked to construct a new sentence. This is not that surprising – memories of our recent behavior influence (or prime) our current behavior.

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Jun 06 2011

Anti-Vaxers and the Need for Clarity

Humans are not entirely rational creatures. We all know this from daily experience, although we happily assume that we are more rational than other people (which is just one of our irrationalities). We are motivated by the need for meaning, and for esteem. We tend to pick sides, and then invest our egos in that side, defending it at all costs.

We are also motivated by the need for simplicity and control. The world is a very complex place, overwhelmingly so. Therefore we need to simplify it in our minds, so that we can deal with it. We use schematics, and categories, and rules of thumb to impose a manageable order on the chaos of reality. These devices are quite adaptive, as long as we realize that they are just that – human devices to approximate reality in a way we can handle.

But too often we confuse our simplistic models of reality with reality. Further, we like our morality plays to be black and white. The villains are villains, without redeeming qualities. The good guys wear white and have no major flaws (nothing beyond an endearing quirk). The ambiguities and gray of the world make us feel uncomfortable. This tendency, by the way, leads to certain logical fallacies, such as poisoning the well. If Hitler believed something, and everything Hitler did was bad, then that belief must also be bad.

We can see this need for moral clarity and scientific simplicity at work in the anti-vaccine movement. Their core belief is that vaccines are not safe, that they are causing harm to our children. They are incorrect in this belief, but that is the bedrock of their movement.

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Jun 03 2011

Creationist Politicians

Tennessee is currently debating one of the latest creationist bills – House Bill 368, introduced by representative Bill Dunn. The essence of the bill is this:

Toward this end, teachers shall be permitted to help students understand, analyze, critique, and review in an objective manner the scientific strengths and scientific weaknesses of existing scientific theories covered in the course being taught.

Basically – it’s a “strengths and weaknesses” bill. This is the latest strategy for sneaking creationism into the public schools through the back door. They failed to ban evolution. They failed to force in creationism through “equal time” laws. They failed to sneak in intelligent design (creationism in disguise). So now they are working on two closely related strategies: academic freedom and strengths and weaknesses. They are very clever, but the purpose is exactly the same – water down the teaching of evolution and sneak in as much creationist propaganda as possible.

The language of the bill first sets the stage by saying that evolutionary theory is “controversial.” Of course, it’s only culturally controversial because of creationist denialism. It is not controversial within the scientific community, the overwhelming majority of whom accept evolution as a scientific fact. Then the bill goes on to say that the purpose is just to teach kids (wait, turn down your irony meters) – “critical thinking.”

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Jun 02 2011

The Decline Effect Revisited

I have written previously about the decline effect – the apparent decrease in the magnitude of a phenomenon as it is scientifically studied. Initially there seems to be a big effect, but the effect size shrinks as further research is done, sometimes shrinking all the way to zero.

This effect was perhaps first observed (or at least named) in psi research. Over the last century psi researchers have come up with a number of research paradigms to demonstrate so-called anomalous cognition. But in every case the initial impressive effect sizes have shrunk to non-existence with repetition. While the standard interpretation of this failure to reproduce results is that the phenomenon is not real, some defenders of psi have tried to argue there is a real metaphysical decline effect at work. It’s not their fault – the phenomenon actually goes away over time.

Writing for Naturenews, Jonathan Schooler makes a similar claim about the interpretation of the decline effect in science in general. To be fair, this is not the focus of his article. He is making an argument for registering all scientific studies, so that publication bias cannot distort the patterns of evidence in the literature. I completely agree. But within his article he writes:

Perhaps, just as the act of observation has been suggested to affect quantum measurements, scientific observation could subtly change some scientific effects. Although the laws of reality are usually understood to be immutable, some physicists, including Paul Davies, director of the BEYOND: Center for Fundamental Concepts in Science at Arizona State University in Tempe, have observed that this should be considered an assumption, not a foregone conclusion.

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