NEWS & TECHNOLOGY
Adult chimps are less consoling than their peers later in life. This is the first evidence that chimps have “empathetic personalities”, says Webb. But they also found that juvenile chimpanzees console others more than adults, and infants console most of all the age
THERE, there! Adult chimpanzees are less likely than young ones to console companions in times of distress. The finding raises questions about how the capacity for empathy changes with age in our closest relatives – and us. When a chimpanzee gets upset, companions often sit with them and offer reassurance by kissing, grooming or embracing them. We know chimpanzees have personalities: lasting individual features in their behaviour. But it was unclear whether their empathetic tendencies are part of their personality, and whether they change over time. Christine Webb at Emory University in Atlanta, Georgia, and her colleagues studied eight years of observations of a group of 44 chimpanzees at Yerkes National Primate Research Center. They found that individual differences were consistent over lifespan: chimps who consoled more in their youth, relative to their peers, also consoled more
Snowstorms may rage on Mars at night IF HUMANS ever reach Mars, they may need to beware of blizzards. Violent snowstorms can form in the dead of night, shows a model based on weather data from the Red Planet. Previous simulations suggested that Mars may have had snowstorms when it was wetter in the distant past, and the Phoenix lander saw some gently falling flakes in 2008. But there were few indications that blizzards could happen there now. “It’s the first time anyone has 10 | NewScientist | 26 August 2017
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Sam Wong
shown that snowstorms, or water-ice microbursts, occur presently on Mars,” says Aymeric Spiga at Pierre and Marie Curie University in Paris. “Any snow particles formed were thought to fall only very slowly through their own weight.” Spiga and his colleagues created a model based on data on water-ice clouds from the Mars Global Surveyor and the Mars Reconnaissance Orbiter. They also included observations from the Phoenix lander of an apparent “virga” snowfall, in which snowflakes turn from solid to gas before they reach the surface (Nature Geoscience, DOI: 10.1038/ngeo3008). The model showed that snowstorms form only at night, mainly
groups (Nature Communications, doi.org/cbz5). This doesn’t mean older chimps have less empathy than younger ones, says co-author Frans de Waal, also at Emory University. “I think they become more selective in how they express it. They focus on individuals they’re close to – offspring or friends – whereas the young ones respond to everything emotional.” Similar patterns have been found in bonobos and gorillas. In contrast, humans become more
empathetic through childhood and adolescence. There is evidence that human empathy increases until middle age and then drops, but it comes from self-reporting questionnaires, so some researchers are sceptical. Still, Mariska Kret of Leiden University in the Netherlands proposes a possible explanation: “It may be that older individuals console less, but when they do, they do better.” Webb and de Waal suggest an alternative. They point to previous studies on agreeableness, which involves a sensitivity towards others; and extraversion, a tendency to actively engage with others. In humans and chimpanzees, agreeableness increases with age but extraversion decreases more markedly. The changes in consolation behaviour might simply reflect the latter trend. In addition, a 2013 study measured brain activity while volunteers watched videos of people getting hurt. Older people had weaker emotional responses, but they processed intentionality – whether someone inflicted pain on purpose – similarly. It may be that older people can understand others’ feelings without becoming distressed, which might improve –Creature comforts– their own well-being. n
through cooling of the water-ice particles in clouds once the sun sets. The resulting cold zone creates strong, turbulent plumes of wind as it builds up over warmer, ice-free air. Ice particles get caught in the descending currents and form snow that falls hundreds of times faster than was predicted from the Phoenix observations. Spiga says that although the snow flurries could be violent, many are likely to peter out before any flakes reach the ground. But if a cloud is low enough, the snow
“It’s the first time anyone has shown that snowstorms occur presently on Mars”
could survive long enough to settle. Spiga says his team’s simulations of the Martian atmosphere and clouds were in unprecedented detail. “We happened to discover the occurrence of snowstorms because we used much more sophisticated and fine-scale modelling than done before, allowing us to reinterpret existing measurements that posed mysteries,” he says. “Like on Earth, these clouds play a role in the overall water cycle,” says Scot Rafkin at the Southwest Research Institute in Boulder, Colorado. “They could impact human activities on the surface, whether it be a picnic on Earth or a future science excursion on Mars.” Andy Coghlan n