Monkeys Reject Unequal Pay

In class, while talking about the recognition heuristic, Professor Rettinger showed us a quick clip of two monkeys and their reaction to receiving two different rewards. I found the clip not only amusing due to the fact that the monkey receiving the object that had a lesser value compared to the object the other money received threw a tantrum, but was amazed at how perfectly the video demonstrated the recognition heuristic. I instantly knew I wanted to research more into the topic and experiment.

The recognition heuristic is the idea that if one of two objects is recognized and the other is not, then the recognized object will have the higher value. Sarah F. Brosnan and Frans B. M. de Waal conducted a study to try and understand the evolutionary response to fairness. Fairness is a social ideal therefore cannot be measured, so in order to understand responses to fairness, they conducted a study to observer behavior responses when given equal and unequal rewards.

The study consisted of two brown Capuchin monkeys exchanging tokens with a human experimenter to receive either a grape or cucumber. In this case, the cucumber represents an unequal exchange and a grape represents an equal exchange. In the study before the monkey exchanging tokens with cucumber realizes that the monkey in the cage next to her is receiving grapes, she trades with no behavioral signs of concern or anger for inequality. Once the monkey sees the trade her neighbor is making with the human experimenter compared to the trade she is making with the human experimenter, she immediately starts to react in a negative manner to express her feelings about the unequal trade. She expresses her concern by throwing her cucumber at the experimenter, pounding on the bars of her cage and refusing to take the offer. She continually makes a trade by handing the experimenter a coin with efforts to eventually receive a grape.

What intrigues me most about this experiment is that fact that the monkey is completely content with trading the coin for a cucumber right up until she sees the trade happening with her neighbor that involves a coin and a grape. This is because she assumed the trade to be fair until she saw something that had a higher value. The representative heuristic is demonstrated. Every monkey that was involved in this study refused to participate if they witnessed a conspedic obtain a more attractive reward for equal effort. Their reactions support an evolutionary origin of inequity aversion.

This study also reminds me of the ultimatum game. The ultimatum game is a game in which the first player conditionally receives a sum of money and proposes how to divide the sum between themselves and another player. The second player chooses to either accept or reject this proposal.  Two parts of the brain is active while participating in the ultimatum game. The prefrontal lobe shows more activation when people make a rational decision and the anterior insula is activated when people reject offers. The anterior insula in the brain is responsible for disgust emotions. This shows that people get disgusted when offered an offer they feel is unfair. There is a slight correlation between Sarah F. Brosnan and Frans B. M. de Waal’s study and the ultimatum game as both have something to do with equality and fairness. Both of these ideas have everything to do with our everyday life and human behavior. I have noticed others and even myself get uncomfortable and annoyed when things are not fair. I have posted below the video of a capuchin monkey rejecting unequal pay, I hope y’all find it as interesting as I did.

5 thoughts on “Monkeys Reject Unequal Pay

  1. ktbug

    I find this to be the funniest video!! You did an awesome job with this post. I like how you reflected on the video and even tied it in with the ultimatum game. Unfortunately it is a reminder that sometimes life isn’t fair!

    1. jesseboles Post author

      It is a reminder that life is not fair, however we knew that from the beginning. I is interesting that monkeys have the same negative feelings about life being unfair as we do.

  2. mshifflett4

    I really enjoyed the video, it was very amusing! I think you did a great job of taking something we learned in class and then furthering your research on the topic, as well as tying in other examples and relating them to different cognitive theories. I would like to see if other animals would have this same reaction to the experiment, or if it’s just the monkeys who see the unfair trade happening!

    1. jesseboles Post author

      It would be interesting to see if other animals would have reacted in the same way. I am assuming yes but that would be fun to find out. I am glad you found the video as interesting and amusing as I did.

  3. sjohns25

    I though this video was so funny in class I’m very glad you did your post on it! It is crazy how the monkey reacts when he receives of an unfair payment it reminded me of a little kid not getting his way. I think it relates to so much in the real world. I think this video illiterates how we all feel in life when we are treated unfairly but cant no do anything to change it. I know when I found out some new male employees were making more than me and doing less work I wanted to act just like this monkey did. Thank you for sharing!

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