Apes 'gamble like humans by calculating odds' - Telegraph

Quote:

Research indicates that the animals are also able to calculate the odds before taking risks. Experts observed apes as they gambled using upturned cups concealing pieces of chopped banana. Given the choice of a safe bet of a small piece of banana or a larger chunk of fruit hidden beneath one of a selection of shuffled cups, the apes chose to gamble more than 50 per cent of the time. The team, led by Daniel Haun of the Max Planck Institute for Psycholinguistics found that they were also able to identify when the odds were stacked against them and when it was wiser to go with the safe bet. As more cups were added and the odds became worse, the apes become more cautious. The ability is shared by chimpanzees, bonobos, gorillas and orang-utans, researchers said, although chimps and orang-utans were found to be more prolific risk-takers. “Our study adds to the growing evidence that the mental life of the other great apes is much more sophisticated than is often assumed,” said Mr Haun.

__________________
Standard disclaimer: the disgusting statements contained in this post are the views of the poster, and unless specified do not represent the views of the moderators or the site's owners.

Chimpanzees seem to know what's on other chimps' minds

Humans may not be alone in having insight into the minds of others, a chimpanzee study suggests


guardian.co.uk, Thursday 29 December 2011 17.00 GMT


Chimpanzees moving through the forest take into account other chimps' ignorance or knowledge of a threat when they raise the alarm.

The apes were more likely to make warning calls when they spotted a venomous snake if others in their troop had not seen the danger, researchers found. As chimps in the know arrived at the scene, they passed the warning on to others who lagged behind but were still within earshot.

Video footage of wild chimps foraging in Uganda's Budongo forest show apes at the front of their groups jumping with surprise on spotting a model snake lying camouflaged in the undergrowth.

When the chimps regained their composure, they called out with repeated "hoos" to alert those behind them that a threat lay ahead. They made calls less often when other chimps already knew of the danger.

The behaviour suggests the animals knew what their fellow apes knew and made decisions over what warnings to give based on the information.

"Lots of animals give alarm calls and are more likely to do so if there's an audience, but these chimps are more likely to call if the audience doesn't know about the danger. It's as if they're picking up on differences in ignorance and knowledge in others," said Dr Catherine Crockford, who studies ape communication and social interaction at the University of St Andrews.

"The chimps would sometimes jump when they saw the snake, but they didn't call then. They would only call after going back for a second look. So there's a dissociation between their emotional reaction and the vocalisation. The call is not a knee jerk reaction to the snake, it's intelligent behaviour," she said.

Crockford teamed up with researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig and the Budongo Conservation Field Station in Uganda to investigate how 33 wild chimps reacted to model vipers placed on paths use by apes in the forest.

When confronted with danger, chimps scream or bark if the threat is serious, such as an ambush by a leopard or rival chimp troop. But they respond to less serious threats, such as snakes or fresh faeces from predators, with gentle, repeated "hoo" sounds. Though vipers do not prey on chimpanzees, they can attack with a lethal bite if trodden on or disturbed.

The scientists filmed 111 encounters between the chimps and the model vipers and recorded alarm calls the apes made on spotting the snakes. Most chimps reacted with repeated hoos, and only rarely made more serious barking sounds.

The chimps hoo-ed most when they caught sight of companions who had been too far away to see the snake or hear earlier warning calls. They hoo-ed least when other chimps had seen the viper themselves, according to a report in Current Biology.

On hearing the hoos, some chimps stopped in their tracks and waited. Others picked their way through the forest on detours that took them around the snake.

Crockford said the findings suggest humans are not alone in knowing the minds of others, an ability that may have been pivotal in the evolution of language as it allowed humans to share information and boost collective knowledge.

"More of the essential ingredients needed to kickstart complex communication are evident in chimpanzees than we thought," Crockford said.

Chimpanzees seem to know what's on other chimps' minds | Science | The Guardian