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18 | NewScientist | 23 April 2011 Invisible princess keeps kids honest RELIGIONS can discourage believers from erring for fear that God is watching. Now it seems that children also avoid cheating if told they’re being watched – not by God, but by Princess Alice, an invisible person conjured up by researchers. Thirty-nine young children from Belfast, UK, volunteered to take part in a hit-the-target game designed by Jared Piazza at the University of Kent in Canterbury, UK, and colleagues. But the rules of the game were so tough that success necessitated cheating. While secretly being videoed, each child played the game either with an adult present, with no one present, or with no one except “Princess Alice” present. Beforehand, they were all asked if they believed Princess Alice really existed. Of the 11 children who did, only 1 cheated in her “presence”. Five of the seven disbelievers cheated (Journal of Experimental Child Psychology, DOI: 10.1016/j.jecp.2011.02.003). “This is an interesting example of an audience effect and the drive to preserve our reputation,” says Chris Frith of University College London, who was not involved in the study. Journey beyond our ‘maximum’ pitch perception HUMANS are able to make sense of sounds at a much higher pitch than previously thought. A note has a fundamental tone – the pitch we hear – and a series of overtones that occur at higher frequencies. Overtones are what give a sound its timbre, and enable us to distinguish an oboe from a trumpet from its sound alone. Previous studies have shown that humans are unable to recognise melodies whose notes have a fundamental tone above 5 kilohertz. It was thought that, at frequencies this high, the rapidly cycling sound wave was too fast for the auditory nerve to cope with. To test this theory, Andrew Oxenham and his colleagues at the University of Minnesota in Minneapolis asked a group of six students whether two four-note melodies were identical or not. As in previous studies, the volunteers could not recognise melodies with fundamental tones above 5 kHz. The team then took a fundamental tone pitched below 5 kHz and digitally filtered it to leave just the overtones above 6 kHz. Surprisingly, the volunteers IF THE usual ideas of how bicycles balance themselves are right, this weird contraption ought to quickly topple over. In fact it stays upright, an observation that might lead to a rethink of bicycle dynamics – and perhaps to better bike designs. Push a riderless bike fast enough, and it stays upright for a surprising distance. When it starts tipping to the right or left, the front wheel steers into the fall, correcting the tilt. Earlier studies attributed this in part to the gyroscopic effect of the spinning wheels. But this model, built by Andy Ruina of Cornell University in Ithaca, New York, and colleagues, nullifies the gyroscopic effect with discs that spin in the opposite direction to the wheels. Also, its front wheel is mounted at a much steeper angle than normal – a change expected to make the bike topple. The key to its stability seems to be that the centre of gravity of the handlebars is lower than the frame’s and forward of the steering axis. So when the handlebars start to fall, they do so faster than the frame. This twists the hinge to the front wheel, steering it into a fall (Science, DOI: 10.1126/science.1201959). The shape of bikes to come SAM RENTMEESTER/FMAX were able to distinguish these melodies (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1015291108). Oxenham says there are many potential explanations for the result. One is that if pitch perception is learned through exposure to melodies, it may be possible to recognise a tune even when the fundamental tones are absent. And melodies are rarely, if ever, composed with fundamental tones above 5 kHz, so the brain may be unable to recognise this unfamiliar class of melodies. Who’s the sea snake daddy? GLIDING silently through the ocean, sea snakes are a rarity in more ways than one. Each female allows only one male to father her brood. As a general rule, female reptiles mate with multiple males to produce a single brood. But when Vimoksalehi Lukoschek of James Cook University in Townsville, Queensland, Australia, decided to verify this in elapid snakes, a family that includes cobras and sea snakes, she found something new. Lukoschek looked at 12 pregnant female sea snakes, from six species, that had been killed by fishing trawlers. She took DNA samples from both the females and their unborn offspring, and used 10 chunks of the genome that vary widely to work out how many males contributed to each brood. To her surprise, each brood had only one father (Journal of Heredity, DOI: 10.1093/jhered/esr017). “The contrast with what we’ve seen in other groups is striking,” says Richard King of Northern Illinois University in DeKalb. The pros and cons of single and multiple matings are poorly understood, he adds. The sample size is small, warns Tobias Uller of the University of Oxford. “Three out of six of the species were represented by a single clutch,” he says. Lukoschek says she has no idea why the females are so selective. TIM ROCK/PHOTOLIBRARY IN BRIEF For new stories every day, visit www.NewScientist.com/news
