Chimpanzees successfully play the 'ultimatum game': Confirmation of apes' sense of fairness

Jan 14, 2013
Image: Wikipedia.

Researchers at the Yerkes National Primate Research Center, Emory University, are the first to show chimpanzees possess a sense of fairness that has previously been attributed as uniquely human. Working with colleagues from Georgia State University, the researchers played the Ultimatum Game with the chimpanzees to determine how sensitive the animals are to the reward distribution between two individuals if both need to agree on the outcome.

The researchers say the findings, available in an early online edition of the (PNAS) available this week, suggest a long of the human aversion to inequity as well as a shared preference for fair outcomes by the of humans and apes.

According to first author Darby Proctor, PhD, "We used the because it is the gold standard to determine the human sense of fairness. In the game, one individual needs to propose a reward division to another individual and then have that individual accept the proposition before both can obtain the rewards. Humans typically offer generous portions, such as 50 percent of the reward, to their partners, and that's exactly what we recorded in our study with ."

Co-author Frans de Waal, PhD, adds, "Until our study, the community assumed the Ultimatum Game could not be played with animals or that animals would choose only the most selfish option while playing. We've concluded that chimpanzees not only get very close to the human , but the animals may actually have exactly the same preferences as our own species." For purposes of direct comparison, the study was also conducted separately with human children.

In the study, researchers tested six adult chimpanzees (Pan troglodytes) and 20 human children (ages 2 – 7 years) on a modified Ultimatum Game. One individual chose between two differently colored tokens that, with his or her partner's cooperation, could be exchanged for rewards (small food rewards for chimpanzees and stickers for children). One token offered equal rewards to both players, whereas the other token favored the individual making the choice at the expense of his or her partner. The chooser then needed to hand the token to the partner, who needed to exchange it with the experimenter for food. This way, both individuals needed to be in agreement.

Both the chimpanzees and the children responded like adult humans typically do. If the partner's cooperation was required, the chimpanzees and children split the rewards equally. However, with a passive partner, who had no chance to reject the offer, chimpanzees and children chose the selfish option.

Chimpanzees, who are highly cooperative in the wild, likely need to be sensitive to reward distributions in order to reap the benefits of cooperation. Thus, this study opens the door for further explorations into the mechanisms behind this human-like behavior.

For eight decades, the Yerkes National Primate Research Center, Emory University, has been dedicated to conducting essential basic science and translational research to advance scientific understanding and to improve the health and well-being of humans and nonhuman primates. Today, the center, as one of only eight National Institutes of Health–funded national primate research centers, provides leadership, training and resources to foster scientific creativity, collaboration and discoveries. Yerkes-based research is grounded in scientific integrity, expert knowledge, respect for colleagues, an open exchange of ideas and compassionate quality animal care.

Within the fields of microbiology and immunology, neurologic diseases, neuropharmacology, behavioral, cognitive and developmental neuroscience, and psychiatric disorders, the center's research programs are seeking ways to: develop vaccines for infectious and noninfectious diseases; treat drug addiction; interpret brain activity through imaging; increase understanding of progressive illnesses such as Alzheimer's and Parkinson's diseases; unlock the secrets of memory; determine how the interaction between genetics and society shape who we are; and advance knowledge about the evolutionary links between biology and behavior.

Explore further: Too many chefs: Smaller groups exhibit more accurate decision-making

More information: "Monkeys are perceptually tuned to facial expressions that exhibit a theta-like speech rhythm," by Asif A. Ghazanfar, Ryan J. Morrill, and Christoph Kayser, PNAS, 2013.

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User comments : 12

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lowerarchy
4.4 / 5 (7) Jan 14, 2013
Chimps and children see the sense in sharing amicably, when will the politicians catch up?
Modernmystic
1.5 / 5 (8) Jan 14, 2013
Chimps and children see the sense in sharing amicably, when will the politicians catch up?


When the human race has a radical cultural and philosophical shift. Much like the enlightenment (science trumping the church), or the trend towards self government as an ideal. Both of which were unthinkable 500 years ago.
weezilla
5 / 5 (2) Jan 14, 2013
"Yea, when I was a kid, I was a control group in a study of chimps"
douglaskostyk
5 / 5 (4) Jan 14, 2013
First the politicians need to attain the intelligence of a chimp.
3432682
1.6 / 5 (18) Jan 14, 2013
"Chimps and children see the sense in sharing amicably, when will the politicians catch up?"

Actually, it is the adults who already (naturally) play the game fairly. The research finds that children do too, and even chimps.

Over 50% of our economy is directed by governments (through spending and regulation) which have become welfare state vote-buying machines. The "fair" distribution of the economy (by the welfare state advocates) cripples the entire economy. The majority of voters have not noticed that this "fair" distribution means less for everybody. Those being pilfered for 50% of their income are increasingly unwilling and unable to play the redistribution game.
Jaeherys
2.3 / 5 (3) Jan 14, 2013
And the government is run by who again? Dolphins? Because I don't see us fighting battles by "dancing" our enemies to defeat. What I see are adults doing what adults do best, thinking short term and fighting for high gain at the cost of others, in every aspect of our lives from parts of the government, business, to schools. There is incredible amounts of debate over whos political view is better, which almost certainly ends in pointless blabbering of ones biases. In almost every case the one key factor, and maybe the only factor that is of actual importance is that we are all humans and humans are naturally flawed, i.e. genetically and environmental impacts. If we all treated each other like I would want to be treated myself, it's quite possible that almost any political view would be successful.

Most views have some merit when it comes to helping the general population but the mess we are in is a symptom of our evolved yet animalistic minds, nothing more, nothing less.
zaxxon451
2.3 / 5 (6) Jan 15, 2013
"Chimps and children see the sense in sharing amicably, when will the politicians catch up?"

Actually, it is the adults who already (naturally) play the game fairly. The research finds that children do too, and even chimps.

Over 50% of our economy is directed by governments (through spending and regulation) which have become welfare state vote-buying machines. The "fair" distribution of the economy (by the welfare state advocates) cripples the entire economy. The majority of voters have not noticed that this "fair" distribution means less for everybody. Those being pilfered for 50% of their income are increasingly unwilling and unable to play the redistribution game.


You've been programmed by your 1% slave masters very well. Tell us more about how the American Dream is there for anyone with a positive attitude and a good work ethic!

Wake up.

http://www.youtub...W1vFO-2Q
Arcbird
1 / 5 (10) Jan 15, 2013

"Most views have some merit when it comes to helping the general population but the mess we are in is a symptom of our evolved yet animalistic minds, nothing more, nothing less."

Well said but I think it's rather a result of indoctrination into normality and all it's corrupt values and ideals beginning from birth. Value system disorder so to speak..

perrycomo
1.4 / 5 (11) Jan 15, 2013
So when can we look at a video to see that the experiment in the lab is confirmed in the daily life of a family of chimps in the wild . . Of course we will never see such behavior in the wild , because they only 'learn' because of the rewards they get . It is always the same story with those chimps give them a banana and they will rob a bank or whatever , from that point of view they are as corrupt as their cousins homo sapiens .
Torbjorn_Larsson_OM
5 / 5 (1) Jan 15, 2013
Interesting hominin trait.

@perrycomo: Anthropologists have to make efforts to trigger existing behavior, and not use training. If you go to the papers, they describe how it is done.
Job001
1.8 / 5 (10) Jan 15, 2013
Without trade/sharing cooperation does not happen. Without cooperation higher(productivity) civilization does not happen. Trading/sharing is essential for survival and cooperative civilization.
The conclusion is clear, trade/share or decline(into war or tribal(plutocracy/dictator/king/junta/et al) poverty). Cool! Pure selfish greed is refuted philosophically by monkeys, perhaps someday by man.
Tausch
1 / 5 (6) Jan 20, 2013
...suggest a long evolutionary history of the human aversion to inequity as well as..


...imaginary Selbstüberschätzungen (exaggerated opinion of oneself)

The 'more information' (bottom line) title suggests an entirely different area of research. An incorrect link?

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