Monday Science Links

This week's science:

• At Literal Minded, Neal talks about parents who are linguists and their kids:Her point: Although most parents are interested in their children’s language development, nonlinguists are only interested in the mistakes, the babyish pronunciations, the cute misunderstandings. Linguists, in contrast, are also interested in what the kids get right, the kind of thing that might go right by other parents because it just sounds normal.


• At A Primate of Modern Aspect, something else Ardi told us: knuckle-walking must have evolved twice: We had lots of clues that this was the case before Ardi, but now that we’ve got Ardi- the palmigrade extraordinaire, we know that humans did not go through a knuckle-walking phase, and that chimpanzee knuckle-walking has evolved since the split with our last common ancestor with them. Which would also means that it evolved after our split with the gorillas… which means that knuckle-walking evolved twice. As we’ve discussed before, knuckle-walking is a pretty weird thing to do, which is why the idea that it evolved only once is hard to shake. But once you’ve got a particular body plan, there are only so many ways to accomplish a certain task.


• Julien at A Very Remote Period Indeed looks at an experiment to see if stone-tipped arrows were worth the time they took to make: Nicole Waguespack and a bunch of others (including four of the Mythbusters gang, which leads one to wonder whether this will be the basis of a future episode) ask the question: "Given that so many hunter-gatherers use/d stone-tipped projectile, what are the advantages of a stone tip relative to one whose point is simply sharpened wood?" ResearchBlogging.orgThis is a good question to ask, since crafting an projectile point from stone consumes more time, effort and resources than simply sharpening the end of the shaft that you'll be making anyway. Hell, one could even argue that knapping a stone point incurs some additional risk since you risk slicing up your hand as you do so, as anyone who's ever tried their hand (eh!) at flintknapping knows all too well. These costs are all the more important to keep in mind given the frequency at which stone points break during use (Waguespack et al. 2009:787). As the authors argue, it's generally assumed that stone makes for a more effective projectile point, though this has rarely, if ever, been tested empirically.


• At Magma Cum Laude Jess talks about earthquake scales and what they measure: It's only natural that a lot of news agencies will report natural disasters, and especially large earthquakes. But over and over again, I hear even the best reports making the same mistake: using the phrase "the earthquake was an X on the Richter scale." A Google News search for "Haiti earthquake Richter" brings up more than 500 references to news articles that use that phrase. It might seem nitpicky, but it always annoys me when the media can't be bothered to use the correct phrasing to describe earthquakes - it's a small misuse of scientific terminology, but if you take a closer look at it, it's a significant one.


• And Chris at Highly Allocthonous blogs on the plate tectonics of the Haiti earthquake: The Caribbean is contained on its own separate little plate; a rather diminutive part of the tectonic jigsaw that is the Earth's crust. It is surrounded on three sides by the much larger North and South American plates, both of which are moving approximately westwards with respect to the Caribbean plate at around 2-3 centimetres a year. On the eastern edge of the plate, the boundary runs perpendicular to the direction of relative plate motion, so there is compression and subduction (and subduction volcanism, exemplified by the likes of Montserrat). However, as the boundary curves around to form the northern boundary of the Caribbean plate, where the Haitian earthquake occurred, it starts to run parallel to the direction of relative plate motion, making strike-slip faulting along E-W trending faults the most likely expression of deformation in this region. This is exactly what the Haitian quake appears to record.

Enjoy!