September 25, 2009
Sabre-toothed cats had weak bites – a new comparison of Smilodon‘s skull with a modern lion’s shows that the cat probably didn’t run up and bite its prey with those teeth. Probably it brought prey down with a full-body tackle (it had extra strong claws) and then used the famous teeth to make the kill once it had the animal pinned. At least, that’s the latest theory.
Velociraptor’s ‘killing’ claws were for climbing – I’m just ruining all the prehistoric artists’ conceptions today, aren’t I? Analyses of velociraptor claws shows they weren’t sharp enough to disembowel prey, but were strong enough to hold the dinosaur’s weight as it climbed trees.
Kids, even babies, judge others based on skin color – and we exacerbate the problem by keeping the subject taboo. The author writes of his own son: “Katz’s work helped me to realize that Luke was never actually colorblind. He didn’t talk about race in his first five years because our silence had unwittingly communicated that race was something he could not ask about. … we started to overhear one of his white friends talking about the color of their skin. They still didn’t know what to call their skin, so they used the phrase ‘skin like ours.’ And this notion of ours versus theirs started to take on a meaning of its own.”
Swine flu vaccine: Too little, too late (SciAm article, first half available online) – When you’re trying to make enough flu vaccine, boosting production with new methods and adjuvants is at odds with safety and testing (and the potential for lawsuits). The author seems to think litigation is the problem; but if people are suing because they’ve been harmed by the vaccine, wouldn’t it be more correct to say safety is the problem? Deciding how much risk is appropriate is a tough question.
Jell-O shots in adolescence lead to gambling later in life – When you want to study alcohol and risky behavior in rats, do it right! Yes, they really fed the rats jell-o shots, and taught them to gamble.
Scientific American: With a wave of the hand: how using gestures can make you smarter – New research shows that students who make a certain gesture while solving a certain type of math problem do better when tested. One hypothesis: the gesture (incorrectly described as a “V” shape in the SciAm article) somehow teaches the concept of combining two numbers. My take: it sounds more like associating the concept with a gesture gives you an anchor to remember the concept. Like the parking garages that use a different color of signage on each floor, or the old-fashioned concept of tying a string around your finger.
The paper itself (free!) says that speaking a mantra didn’t do as well as the gesture (the gesture and mantra together worked very slightly better than the gesture alone). Both worked OK for the immediate post-test, but the gesturers did better on a follow-up test. The authors say that “These findings suggest that using the body to represent ideas may be especially helpful in constructing and retaining new knowledge.”
I wonder whether the gesture may have also helped children who learn well with spatial or visual mnemonics. The gesture involved sliding your left hand under the left side of the equation and your right hand under the right side of the equation. To me that would say this side has to be like that side, in a way that would stick, for me, better than the equivalent spoken mantra: “I want to make one side equal to the other side”.
Here are the authors’ thoughts on how gesture might help memory:
One possibility is that gesture offers a representational format that requires relatively little effort to produce, thereby freeing resources that can then be used to encode new information in a more lasting format. Indeed, expressing information in speech and gesture has been shown to place less demand on working memory than expressing the same information in speech alone … Another possibility is that gesturing directly facilitates encoding in long-term memory. Expressing information in gesture may produce stronger and more robust memory traces than expressing information in speech because of the larger motor movements involved or because of the potential for action-based, bodily encoding. Indeed, when speakers are asked to use their hands to act out an event conveyed in a sentence, their memory for the event is better than if they merely read the sentence or translate it into another spoken language. … Similarly, children understand stories better when they enact the story with objects or imagine enacting the story with objects than when they read the story twice … and actors recall the lines they produce while moving better than the lines they produce while standing still.
Gesture may also affect learning by engaging the external environment. Gestures, particularly pointing gestures that indicate objects and locations in the world, may make it easier for learners to link developing mental representations to relevant parts of the external environment. This type of grounding could then decrease errors in encoding and lighten processing demands … while at the same time facilitating new insights into the problem.