Featured Research

from universities, journals, and other organizations

Apes unwilling to gamble when odds are uncertain

Date:
November 30, 2010
Source:
Duke University
Summary:
Humans are known to play it safe in a situation when they aren't sure of the odds, or don't have confidence in their judgments. We don't like to choose the unknown. And new evidence is showing that chimpanzees and bonobos, our closest living primate relatives, treat the problem the same way we do.

A pair of bonobos enjoy banana slices at the Lola ya Bonobo sanctuary.
Credit: Vanessa Woods

Humans are known to play it safe in a situation when they aren't sure of the odds, or don't have confidence in their judgments. We don't like to choose the unknown.

And new evidence from a Duke University study is showing that chimpanzees and bonobos, our closest living primate relatives, treat the problem the same way we do.

In studies conducted at the Tchimpounga Chimpanzee Sanctuary in Republic of Congo and Lola ya Bonobo Sanctuary in Democratic Republic of Congo, researchers found the apes prefer to play it safe when the odds are uncertain.

Graduate student Alexandra Rosati and Brian Hare, an assistant professor of evolutionary anthropology, asked 16 chimps and 14 bonobos to make choices between two bowls of treats.

Though no dice or chips are involved, this kind of experiment is considered a "gambling game," Rosati said. The apes could choose between a safe bet that would always provide a food they liked somewhat less, peanuts, or a variable bet in which the payout could be either a highly-preferred big piece of banana or less-desirable cucumber slice.

The apes "gambled" by making a choice of one bowl or the other. They knew the odds before they chose because the experimenter showed them bowls with two potential outcomes, but then gave them only one. Depending on the contents of the bowls, there could be a 100 percent chance of receiving a banana, a 50 percent chance, or a 0 percent chance.

The apes readily distinguished between the different probabilities of winning: they gambled a lot when there was a 100 percent chance, less when there was a 50 percent chance, and only rarely when there was no chance.

In some trials, however, the experimenter didn't remove a lid from the bowl, so the apes couldn't assess the likelihood of winning a banana.

The odds from the covered bowl were identical to those from the risky option: a 50 percent chance of getting the much sought-after banana. But apes of both species were less likely to choose this ambiguous option.

They were willing to take the chance on the covered bowl when they knew the only alternative was food they didn't like (the cucumber), or no food at all. But, like humans, they showed "ambiguity aversion" -- preferring to gamble more when they knew the odds than when they didn't.

Given some of the other differences between chimps and bonobos, Hare and Rosati had expected to find the bonobos to be more averse to ambiguity, but that didn't turn out to be the case.

Researchers looking for the foundations of economic decision-making have been doing studies like this on a variety of species, but these two apes are the two species most closely related to humans, Rosati said.

"These results suggest that understanding how animals forage may be more complex than previously thought," Rosati said.

Decision-making matters to animals in the wild who have to make choices about which resources to pursue on the fly, without knowing if their choices will pay off. "It may be that different decision mechanisms come into play when animals are faced with choices when they have incomplete knowledge," Rosati said.

"These results also suggest that some of our human economic biases may be evolutionarily ancient, predating modern markets: chimpanzees and bonobos act just like us when faced with a primate slot machine," Rosati said.


Story Source:

The above story is based on materials provided by Duke University. Note: Materials may be edited for content and length.


Journal Reference:

  1. A. G. Rosati, B. Hare. Chimpanzees and bonobos distinguish between risk and ambiguity. Biology Letters, 2010; DOI: 10.1098/rsbl.2010.0927

Cite This Page:

Duke University. "Apes unwilling to gamble when odds are uncertain." ScienceDaily. ScienceDaily, 30 November 2010. <www.sciencedaily.com/releases/2010/11/101129203344.htm>.
Duke University. (2010, November 30). Apes unwilling to gamble when odds are uncertain. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2010/11/101129203344.htm
Duke University. "Apes unwilling to gamble when odds are uncertain." ScienceDaily. www.sciencedaily.com/releases/2010/11/101129203344.htm (accessed July 28, 2014).

Share This




More Plants & Animals News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Newsy (July 28, 2014) The asteroid that killed the dinosaurs struck at the worst time for them. A new study says that if it hit earlier or later, they might've survived. Video provided by Newsy
Powered by NewsLook.com
Raw: Sea Turtle Hatchlings Emerge from Nest

Raw: Sea Turtle Hatchlings Emerge from Nest

AP (July 27, 2014) A live-streaming webcam catches loggerhead sea turtle hatchlings emerging from a nest in the Florida Keys. (July 27) Video provided by AP
Powered by NewsLook.com
Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins