Skeptics' Circle #83

The 83rd edition of the Skeptics' Circle is out at Mike's Weekly Skeptic Rant. He does a very good job, so check it out. My contribution to this edition is "Five Oft Repeated Medical Myths". Other entries to check out: Aardvarchaeology on a case of sibling incest in Germany; Skeptico explaining (AGAIN) that Darwinism is not responsible for Nazism; and Bug Girl's Blog on a (possibly real) pubic lice fad (no, really).

Geckos rock

So I was lying on my bed the other day when I noticed a gecko hunting around the light on the roof of my bedroom. As I'm used to geckos running around everywhere, usually I don't pay too much attention, but that day I did. I watched this particular gecko hunt (unsuccessfully as it turned out) and was amazed to discover how much it used its tail to maneuver. Specifically, it coiled up its tail and used it as a kind of spring to launch it towards its query. Pretty cool stuff, I thought, and another example of evolution's ingenuity.

Today, I was pleasantly surprised to come across a new study in PNAS on geckos and their tails. The abstract:

Geckos are nature's elite climbers. Their remarkable climbing feats have been attributed to specialized feet with hairy toes that uncurl and peel in milliseconds. Here, we report that the secret to the gecko's arboreal acrobatics includes an active tail. We examine the tail's role during rapid climbing, aerial descent, and gliding. We show that a gecko's tail functions as an emergency fifth leg to prevent falling during rapid climbing. A response initiated by slipping causes the tail tip to push against the vertical surface, thereby preventing pitch-back of the head and upper body. When pitch-back cannot be prevented, geckos avoid falling by placing their tail in a posture similar to a bicycle's kickstand. Should a gecko fall with its back to the ground, a swing of its tail induces the most rapid, zero-angular momentum air-righting response yet measured. Once righted to a sprawled gliding posture, circular tail movements control yaw and pitch as the gecko descends. Our results suggest that large, active tails can function as effective control appendages. These results have provided biological inspiration for the design of an active tail on a climbing robot, and we anticipate their use in small, unmanned gliding vehicles and multisegment spacecraft.

The Economist on the science of religion

The always fabulous Economist has a very good article on the scientific examination of religion this week. The article focuses on the (ingeniously-entitled) Explaining Religion project (pdf) that is being funded by the European Union. As The Economist explains:

Religion cries out for a biological explanation. It is a ubiquitous phenomenon—arguably one of the species markers of Homo sapiens—but a puzzling one. It has none of the obvious benefits of that other marker of humanity, language. Nevertheless, it consumes huge amounts of resources. Moreover, unlike language, it is the subject of violent disagreements. Science has, however, made significant progress in understanding the biology of language, from where it is processed in the brain to exactly how it communicates meaning. Time, therefore, to put religion under the microscope as well.

The Paleolitihic diet

One of the things I love about Wikipedia is the large number of good articles on strange or obscure topics. Today's featured article (i.e. a very high quality article placed on Wikipedia's main page) is a perfect example: Paleolithic-style diet. So we all know the standard evolutionary psychology view that human beings are adapted to the Pleistocene, not to modernity. As a result, our taste for sugary, fatty and salty foods is maladaptive when supermarkets and fast food restaurants abound. The Paleolithic diet (aka paleo diet, caveman diet, Stone Age diet or hunter-gatherer diet) starts from a very similar view and advocates a diet consisting of:

wild plants and animals that humans and their close relatives habitually consumed during the Paleolithic (the Old Stone Age), a period of about 2 million years duration that ended about 10,000 years ago when Homo sapiens developed agriculture... Building upon the principles of evolutionary medicine, this nutritional concept is based on the premise that modern humans are genetically adapted to the diet of their Paleolithic ancestors and that human genetics have scarcely changed since the dawn of agriculture, and therefore that an ideal diet for human health and well-being is one that resembles this ancestral diet. Proponents of Paleolithic-style diets differ in their dietary prescriptions, but all agree that people today should eat mainly meat, fish, vegetables, fruit, roots and nuts, and avoid grains, legumes, dairy products, salt and refined sugar.

AIDS Denialism in South Africa

Nicolli Natrass, an economist at the University of Cape Town (who, for the record, taught me a fantastic course on the economic problems of Africa), had a great article about AIDS denialism in Skeptical Inquirer last year. The article, "Aids Denialism vs. Science", documents in detail how dangerous unscientific thinking can be - in this case, hundreds of thousands if not millions of people were harmed. Concludes Natrass:

People in positions of authority, be they statesmen like Mbeki or parents like Maggiore, hold the lives of others in their hands. For them to reject science in favor of AIDS denialism is not only profoundly irresponsible but also tragic. But responsibility for unnecessary suffering and death rests also with the AIDS denialists who promote discredited and dangerous views and encourage people to reject scientifically tested treatments.

Kanazawa smackdown

Satoshi Kanazawa is not exactly being welcomed in the science bloggging community. I led the way with a rapid response to his irresponsible call for nuclear genocide, then Cosma Shalizi had a go (as I mentioned yesterday) and now PZ Myers - author of the world's most widely read science blog - roasts Kanazawa as well. I'm sure there will be much more to come...

Homo floresiensis update II

See also my earlier pieces: "The floresiensis mess" and "Homo floresiensis update".

Yet more about whether the Flores specimens discovered in 2004 constitute a new species, this time on the positive side. In an upcoming article in the Proceedings of the National Academy of Sciences, paleoanthropologists Adam Gordon, Lisa Nevell, and Bernard Wood of George Washington University argue a statistical analysis of one of the skulls (LB1) reveals the Flores specimens cannot be shrunken Homo sapiens. Intriguingly, they say the skull most closely resembles Homo habilis, a very primitive hominid indeed. Says Gordon: "This is particularly exciting because ... it suggests that we really do have a hominin lineage that split off from our own as much as 1.7 million years ago, yet persisted up until the time when modern humans started peopling the Americas. That's pretty cool."

When the study goes online, I'll update this entry with a link to it.

Update: the article can be found here.

Encephalon 41

Encephalon #41 is out at Pure Pedantry. Entries to check out: The Phineas Gage Fan Club on domain-specificity in the visual system; Advances in the History of Psychology on how the term 'industrial psychology' may have been the result of a typo; and Neuroanthropology on dissociation strategies for peak performance.