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How we learn to laugh and groan
THIS WEEK
Born to laugh, but we learn to cry Andy Coghlan
understandable to others,” says Sauter, whose team is presenting preliminary results as a poster at a conference held by the Acoustical Society of America next week in Cancun, Mexico. Sauter suggests that laughter and smiling probably both evolved as important communication signals to help avoid confrontation by increasing empathy. “Even other primates laugh, if you tickle a gorilla or orang-utan,” she says. “I think this is a really novel way of looking at emotional expressions, by investigating how vocalisations develop in the absence of auditory feedback,” says Sophie Scott of London’s Institute of Neuroscience. “The laughter finding makes a great deal of sense, and laughter has been described as more like a different way of breathing than a way of speaking.” David Ostry, who studies vocalisation in deaf people at McGill University in Montreal, Canada, says that deaf people may learn to laugh by watching how hearing people do it. Sauter agrees this is possible and has set up an experiment to investigate this. By discovering more about when deaf people vocalise instinctively and when they need to learn, Sauter says, it may be possible to better interpret distress calls from –Phew! That was close– deaf infants. Andy Coghlan n Tracy A. Woodward/The Washington Post/Getty
EVER wondered how many of our everyday laughs, groans and sighs are instinctive rather than learned from our peers? It now seems that only expressions of laughter and relief are instinctive, whereas other emotional outbursts need to be learned from other people. To find out which sounds are instinctive, a team led by Disa
Sauter of the Max Planck Institute for Psycholinguistics in Nijmegen, the Netherlands, asked eight deaf and eight hearing individuals to vocalise nine different emotions, but without words. These included fear, relief, anger, hilarity, triumph, disgust and sadness. Afterwards, Sauter and her colleagues played back the recordings to a panel of 25 hearing individuals, and asked
them to match each utterance to an emotion. It turned out that the only two easily identifiable emotional sounds made by the deaf participants were laughter and sighs of relief. “They seem to be the strongest,” says Sauter. The panel found it easier to guess all the other emotions if the sounds came from the hearing individuals. Even screams of terror were much less obvious from those who were deaf. “This means that for many kinds of emotional sounds, hearing the sounds of others is an important part of development for our sounds to be
Countdown to ‘thermogeddon’ has begun THERE may come a point, if the world warms enough, when parts of the tropics will become so hot and humid that humans will not be able to survive. Models predict that this could start to happen in places in as little as 100 years in the worst case scenario. Now, observations show the process is already under way. As humidity rises, sweating cools 10 | NewScientist | 13 November 2010
us less, so we suffer heat stress at lower air temperatures. For now, no place on Earth exceeds the human threshold for heat tolerance, with the exception of a few caves like the Naica cave in Mexico. That is thanks to a fortunate natural thermostat: when humid air gets hot, it rises and causes storms that cool things down. But there is a catch. The point at which air begins to rise – the stability threshold – depends on how warm and moist surrounding air is. Models predict that as the entire tropics warm, the stability threshold will rise. Nathaniel Johnson and Shang-Ping
Xie at the University of Hawaii studied satellite and rain-gauge data from the last 30 years and found that sea surface temperatures in the tropics now need to be about 0.3 °C higher than they did in 1980 before the air above rises and produces rain (Nature Geoscience, DOI: 10.1038/ ngeo1008). This means the stability threshold has already started to
“Some tropical areas could get too hot and humid on occasion for humans to survive”
rise, says Johnson. He adds that the same should be true over land masses in the tropics. Earlier this year, Steven Sherwood at the University of New South Wales in Australia pointed out the serious implications for humans. Heatwaves already kill tens of thousands of people every year, and even more will die as the thermostat rises. Eventually, some tropical areas could get so hot and humid on occasion that even someone standing naked in the shade in front of a fan would die (New Scientist, 23 October, p 36). Michael Le Page n
Born to laugh, but we learn to cry Andy Coghlan
understandable to others,” says Sauter, whose team is presenting preliminary results as a poster at a conference held by the Acoustical Society of America next week in Cancun, Mexico. Sauter suggests that laughter and smiling probably both evolved as important communication signals to help avoid confrontation by increasing empathy. “Even other primates laugh, if you tickle a gorilla or orang-utan,” she says. “I think this is a really novel way of looking at emotional expressions, by investigating how vocalisations develop in the absence of auditory feedback,” says Sophie Scott of London’s Institute of Neuroscience. “The laughter finding makes a great deal of sense, and laughter has been described as more like a different way of breathing than a way of speaking.” David Ostry, who studies vocalisation in deaf people at McGill University in Montreal, Canada, says that deaf people may learn to laugh by watching how hearing people do it. Sauter agrees this is possible and has set up an experiment to investigate this. By discovering more about when deaf people vocalise instinctively and when they need to learn, Sauter says, it may be possible to better interpret distress calls from –Phew! That was close– deaf infants. Andy Coghlan n Tracy A. Woodward/The Washington Post/Getty
EVER wondered how many of our everyday laughs, groans and sighs are instinctive rather than learned from our peers? It now seems that only expressions of laughter and relief are instinctive, whereas other emotional outbursts need to be learned from other people. To find out which sounds are instinctive, a team led by Disa
Sauter of the Max Planck Institute for Psycholinguistics in Nijmegen, the Netherlands, asked eight deaf and eight hearing individuals to vocalise nine different emotions, but without words. These included fear, relief, anger, hilarity, triumph, disgust and sadness. Afterwards, Sauter and her colleagues played back the recordings to a panel of 25 hearing individuals, and asked
them to match each utterance to an emotion. It turned out that the only two easily identifiable emotional sounds made by the deaf participants were laughter and sighs of relief. “They seem to be the strongest,” says Sauter. The panel found it easier to guess all the other emotions if the sounds came from the hearing individuals. Even screams of terror were much less obvious from those who were deaf. “This means that for many kinds of emotional sounds, hearing the sounds of others is an important part of development for our sounds to be
Countdown to ‘thermogeddon’ has begun THERE may come a point, if the world warms enough, when parts of the tropics will become so hot and humid that humans will not be able to survive. Models predict that this could start to happen in places in as little as 100 years in the worst case scenario. Now, observations show the process is already under way. As humidity rises, sweating cools 10 | NewScientist | 13 November 2010
us less, so we suffer heat stress at lower air temperatures. For now, no place on Earth exceeds the human threshold for heat tolerance, with the exception of a few caves like the Naica cave in Mexico. That is thanks to a fortunate natural thermostat: when humid air gets hot, it rises and causes storms that cool things down. But there is a catch. The point at which air begins to rise – the stability threshold – depends on how warm and moist surrounding air is. Models predict that as the entire tropics warm, the stability threshold will rise. Nathaniel Johnson and Shang-Ping
Xie at the University of Hawaii studied satellite and rain-gauge data from the last 30 years and found that sea surface temperatures in the tropics now need to be about 0.3 °C higher than they did in 1980 before the air above rises and produces rain (Nature Geoscience, DOI: 10.1038/ ngeo1008). This means the stability threshold has already started to
“Some tropical areas could get too hot and humid on occasion for humans to survive”
rise, says Johnson. He adds that the same should be true over land masses in the tropics. Earlier this year, Steven Sherwood at the University of New South Wales in Australia pointed out the serious implications for humans. Heatwaves already kill tens of thousands of people every year, and even more will die as the thermostat rises. Eventually, some tropical areas could get so hot and humid on occasion that even someone standing naked in the shade in front of a fan would die (New Scientist, 23 October, p 36). Michael Le Page n