Posted on 09/17/2003 7:31:01 PM PDT by ZinGirl
Monkeys Demand Equal Pay
12:27 p.m. EDT September 17, 2003
A fair shake is a fair shake -- whether you're a human or a monkey.
A recent study shows brown capuchin monkeys refused to play along when they saw another monkey get a better payoff for performing the same work.
The monkeys were trained to trade a granite token for a piece of cucumber. When the reward was the same for both monkeys, they took the cucumber 95 percent of the time.
But it was a different story when one monkey was given something better -- namely, a grape. Then, the other monkey often pitched a fit -- either throwing the token, refusing to eat the cucumber or giving it to the other monkey.
An Emory University researcher says the results could mean man and monkey have an evolutionary sense of fairness -- which may have helped species cooperate and survive.
MONKEYS REJECT UNEQUAL PAY
PDF of Brosnan, SF & de Waal, FBM "Monkeys Reject Unequal Pay" Nature 425: 297-299
Yerkes Press Release Nature Press Release
For further information, please contact Sarah Brosnan at sbrosna@emory.edu Sarah Brosnan's Homepage
Frans de Waal's Homepage
Capuchin Lab Homepage
Summary of "Monkeys Reject Unequal Pay"
During the evolution of cooperation, it may have become worthwhile for individuals to compare their own payoffs to those of others, in an effort to increase relative fitness.
Humans do so, frequently rejecting payoffs that are perceived as unfair (even if they are advantageous). While there is some variation, this response is widespread across human populations. If a sense of fairness did evolve to promote cooperation, some nonhuman animals may exhibit inequity aversion as well.
This is particularly likely in social species with tolerant societies, such that individuals may reasonably expect some equity between themselves and other group members.
Here we examine the response of five female capuchin monkeys to an unequal distribution of rewards during experimental exchange with a human experimenter. Females in pairs alternated exchanges with the experimenter under four conditions:
1) both females received the same reward,
2) one female received a superior reward,
3) one female received a superior reward without exchange (i.e. no work), and
4) a single female observed a superior reward in the absence of a partner.
Females were significantly less likely to complete an exchange when their partner received a higher-value food item than they, and this response was amplified if the partner received the reward without working for it. Refusals to exchange included passive rejections, such as refusing to either return the token or accept the reward, as well as active rejections, such as throwing the token or the reward out of the testing area. Whereas the basis of this response is unknown (e.g. social emotions, as proposed for humans), negative responses to this type of situation support a relatively early evolutionary origin of inequity aversion.
You need to hang out more with a better class of monkey.
We can't get a raise & "they" can't get new hires to come in for cucumbers ($10hr.), so "they" are offering grapes ($11hr ad in paper) to try to get new hires yet us already hired & working monkeys are still getting . . ., well, I can't say it.
Story developing, should be interesting.
What do you think we should do?
We are not "organized", we're monkeys!
That last bit doen't sound very "commie" to me. I wonder what was going on in their little monkey heads?
No human of whatever ideology would react like that.
Try the same experiment with pigs.
hmmm...depends on what Isabel does....I may be stealing cucumbers and grapes by this weekend.
(did I read that study right? why did they only study the female monkeys, anyway?)
Later, an older monkey I work with informed me that trying to ask my boss for a raise
"would waste my time & just annoy the boss".
"He made that, kay påsa, sound again"
JOHN WHITFIELD
Monkeys strike for equal pay. They down tools if they see another monkey get a bigger reward for doing the same job, US researchers have found.
The experiments show that notions of justice extend beyond humans, says Sarah Brosnan of Emory University in Atlanta, Georgia. This is probably an innate ability that evolved in our primate ancestor, she believes: "You need a sense of fairness to live in large, complex groups."
Brosnan and her colleague Frans de Waal taught brown capuchin monkeys (Cebus apella) to swap plastic tokens for food. Normally, monkeys were happy to exchange a token for some cucumber.
But the monkeys took offence if they saw a neighbour getting a grape for a token. In about half of such trials, the short-changed capuchin either refused to hand over its token, or rejected the reward. Some threw the token or cucumber clean out of their cage.
The animals' umbrage was even greater if another monkey got a grape for nothing. About 80% rebelled in some way in this situation.
"It's a really neat discovery," says primatologist Charles Janson of the State University of New York at Stony Brook. "The monkey is clearly paying attention to what its neighbour is doing, and realizing that it's getting a better reward."
But it's not clear how important this ability is in the forests of South America, where the brown capuchin lives, warns Janson. "Capuchin monkeys can learn to do all sorts of things in captivity that they never do in the wild," he says.
Capuchins don't hold a grudge, says Brosnan. They worked with her on future trials, and the inequality did not create trouble between animals. "The monkeys were clearly not thrilled, but they weren't visibly anxious," she says.
Only female monkeys show this pique, the researchers found. Males were much less sensitive to inequality. Their minds may have been on other things, says Janson: "Males care about sex, and females care about food. The males might not consider the food differences worth worrying about."
Previous experiments with humans have shown that they become less cooperative if treated unfairly, and punish uncooperative people even if their own reward declines as a result. This is akin to a monkey throwing away the cucumber that it has already worked for. Brosnan is now studying chimps to see if they share this trait with us and capuchins.
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