Apes are tempted by gambling even when the odds are against them - Daily Mail

Scientists at Duke University found apes are susceptible to positive 'spin'
They offered one piece of fruit with a 50% chance of getting a bonus piece
In other tests the researchers offered two pieces and removed one of them
The apes were more likely to choose fruit in the first test than the second
The findings may help explain the roots of our own 'glass half full' thinking

Published: 12:40 EST, 12 February 2015 | Updated: 13:25 EST, 12 February 2015

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Chimpanzees and bonobos are just as susceptible to the enticement of winning the lottery as their human cousins are.

A study conducted by biologists at Duke University has shown that the primates - our closest living animal relatives - will choose to gamble food if they think they have a chance of winning more.

However, if they are offered the same odds but believe they might lose, then they will be less inclined to play.

A study conducted by biologists at Duke University has shown that the bonobos (pictured) will choose to gamble food if they think they have a chance of winning more. However, if they are offered the same odds but believe they might lose, then they will be less inclined to play

This is thought to be similar to the kind of economic biases - the hope of getting more despite the odds - that drive humans to play the lottery.

In this case, the prospect of winning a life-changing amount of money makes people ignore the extremely high odds against them.

However, if they are told that they are more than likely to lose the money they use to buy a lottery ticket or to place a bet, they are less inclined to take the risk.

The researchers behind the study said that their findings could help to provide clues about the evolution of traits that make humans susceptible to marketing and spin.

CHIMPS CAN LEARN NEW 'LANGUAGES'

Chimpanzees have special 'words' that they use for different types of food and can even learn the calls used by strangers from foreign groups.

Primatologists have found that a group of adult chimpanzees from a safari park in Holland adapted the grunts they produced for foods like apples to match those of other chimps they lived with in Edinburgh.

Their findings are the first evidence that chimpanzees can learn calls referring to specific foods or objects.

Many scientists have assumed that one of the defining features of human language is that objects and events can be named with different words or symbols depending on the culture.

the researchers, whose findings are published in the journal of Current Biology, watched a group of adult chimpanzees from Beekse Bergen Safari Park in the Netherlands were moved to join a group of chimpanzees in Edinburgh Zoo.

By analysing the acoustic structures of the calls they produced for apples, they found that the two groups of animals had different calls for the fruit before they were put together in 2010.

While the Dutch chimps used high pitched grunts the Edinburgh chimps used far lower and softer sounds.

After a year of integration, the grunt calls for apple were still different, but after three years the calls produced by the Dutch chimpanzees had changed to match those produced by those from Edinburgh.

Christopher Krupenye, a behavioural biologist at Duke University who is the lead author of the study, said: 'People tend to prefer something more when you accentuate its positive attributes than when you highlight its negative attributes, even when the options are equal.

'The lottery is a good example of a context in which attribute framing can be very influential.

'Highlighting the five people who won 10 million pounds (the 0.00001%) will much more effectively encourage people to purchase lottery tickets than highlighting the 99.99999% who won nothing.

'Historically, researchers thought these kinds of biases must be a product of human culture, or the way we're socialized, or our experience with financial markets.

'But the fact that chimps and bonobos, our closest living primate relatives, exhibit the same biases suggests they're deeply rooted in our biology.

'That means it's very difficult to overcome these biases, but it is possible to create environments that might help us make better choices.'

The researchers, whose work is published in the journal Biology Letters, conducted experiments on 23 chimps at the Tchimpounga Chimpanzee Sanctuary in the Republic of Congo and 17 bonobos Lola ya Bonobo Sanctuary in the Democratic Republic of Congo.

The apes were offered a choice between two snacks - a handful of nuts and some fruit.

In one series of trials, the researchers framed the fruit option positively - by offering one piece of fruit, with a 50 per cent chance of a surprise bonus piece.

In another series of trials, the researchers framed the fruit option negatively.

This time they offered two pieces of fruit rather than one, but if the apes chose the fruit, half the time they were shortchanged and received only one piece instead.

Chimps and bonobos were more likely to choose the fruit over the nuts when they were offered a smaller amount of fruit but sometimes got more, versus when they were initially offered more but sometimes got less - despite receiving equal average payoffs in both scenarios.

The preference for the option framed as a prize rather than a penalty was especially strong in males, the researchers found.

Dr Alexandra Rosati, a psychologist at Yale University who took part in the study, said: 'I think this might be similar to how people respond to playing the lottery or gambling.

Kiki, a chimpanzee at Tchimpounga Chimpanzee Sanctuary in the Republic of Congo, was found to also have a 'glass half full' attitude when offered the right kind of reward that has implications for our evolutionary past

'For example, if you think "I have a 10 per cent chance of winning" that sounds a lot better than "I have a 90 per cent chance of losing" - even though the situations are completely equivalent.

'The idea is that emphasising the positive attribute of you chance of hitting the jackpot makes it seem a lot more attractive than emphasizing the negative attribute.'

This bias is the same as the kind of behaviour that sees people say they are more willing to recommend a medical procedure when they are told it has a 50 per cent chance of success compared to when it has a 50 per cent chance of failure.

It is this subtle psychological difference that advertising executives have been taking advantage of for decades.

Dr Rosati added: 'I think these primate studies can tell us a lot about human biases.

'When people make decisions that appear "irrational," it is often not clear why.

'Perhaps people learned to respond that way due to socialization or culture. Perhaps the kinds of experiences we have as people who use money in economic markets causes this bias.

'But animals do not have these kinds of human-specific experiences - so when our closest primate relatives show the same "irrational" responses, that suggests that these economic biases have deep biological roots.'