Monday Science Links

This week's heaping helping of sciency goodness:

• Mark Liberman at Language Log reports on an amazing study on hearing chords: At one point, a grad student in psychology at Yale got the idea to see whether the phenomenon of "categorical perception" applied to tones in the context of musical chords. His basic idea was to create a continuum of stimuli from (say) a major triad to a minor triad, with the middle note moving in steps of (say) a tenth of a semitone from a minor third to a major third relative to the root, and then to compare discrimination and classification accuracy along this continuum. He asked for help, and so I made him a suitable set of stimuli (using Max Mathews' MUSIC program on Peter Denes's DDP-224), and sent him happily back to New Haven. But a couple of weeks later, he was back with bad news. To screen his subjects, he'd run them first in a simple ABX discrimination task on the two end-points of the continuum. These subjects were the usual undergrad psychology students, further selected as having normal hearing and being especially interested in music. However, most of them did surprisingly badly, on a task that should have been trivial, and about a third of them performed at chance levels. So he figured that we must have screwed up the stimuli.


• Ethan at Starts With A Bang wonders why Ptolemy called Sirius red: Astronomy was, arguably, the very first science that was approached scientifically. Since ancient times, astronomical observations were made first, and then models were made to explain those observations. Perhaps the most famous ancient astronomer, Ptolemy, wrote in his Almagest a list of six very bright red stars in the sky... Sirius, the single brightest star in the night sky. Only, take a look at Sirius up there. Does something strike you as different about Sirius from the other five? Yes, they're all very bright, but Sirius, unlike the others, looks blue!


• At Not Exactly Rocket Science Ed looks at the question what colors (or colours, as he says) were dinosaur feathers? (How things change. Feathers? Yeah...): The fossils of some small meat-eating dinosaurs were covered in filaments that are widely thought to be the precursors of feathers. And among these filaments, a team of Chinese and British scientists have found the distinctive signs of melanosomes, small structures that are partly responsible for the colours of modern bird feathers. Melanosomes are packed with melanins, pigments that range from drab blacks and greys to reddish-brown and yellow hues. Their presence in dinosaur filaments has allowed Fucheng Zhang to start piecing together the colours of these animals, millions of years after their extinction. For example, Zhang thinks that the small predator Sinosauropteryx had "chestnut to reddish-brown" stripes running down its tail and probably a similarly coloured crest down its back. Meanwhile, the early bird Confuciusornis had a variety of black, grey, red and brown hues, even within a single feather.


• And speaking of stars that might be blue or red, Phil at Bad Astronomy shows us a brown dwarf that's both: Brown dwarfs are poorly named: they’re not really brown. They’re objects that are too small to really be called stars; they lack the oomph needed to fuse hydrogen into helium in their cores, which is the the mark of a true star. Because of this, they are far cooler than actual stars. Since cool stars are red, you’d think brown dwarfs would actually be reallyred. And they are. Unless they’re blue. Yeah, let me explain this one. First, here are two images of a newly discovered brown dwarf, perhaps the coolest ever seen, and certainly one of the closest to the Earth.


• And finally, Christie Lynn at Observations of a Nerd looks at artificial selection driving speciation - that is, at dogs (fascinating stuff about feral dogs in Moscow, too!): We've turned a fine-tuned hunting animal, the wolf, into a wide variety of creatures, from the wolf-looking shepherds to the bizarre toy breeds. Before domestication, dog's life was tough, but when people pulled specific wolves out of their packs and began breeding them, we changed everything. There were some traits that made this easy - the social structure of wolves, for example, made them predisposed to belonging to a community. But we opened up a number of genetic traits and allowed them to express variety that would have been fatal in the wild. We not only allowed these traits to persist, we encouraged them. We picked dogs that were less aggressive or looked unique. And in doing so, we spurred on rapid diversification and evolution in an unbelievable way.

Enjoy!