Simple Moral Test Clearly Displays Prosociality in Chimpanzees.
A paper released this earlier this week has been first to document spontaneous prosocial behaviour in chimpanzees, finally drawing a line under the question as to whether the welfare of others is considered during choice making in this species; a controversial topic, where such behaviours have been often concluded to be absent in any primate apart from humans (generally from research within the social sciences). This research was carried out at the Yerkes National Primate Research Center by Victoria Horner, and Frans de Waal.
Pairs of chimpanzees (Pan troglodytes) where placed into testing rooms, separated by a mesh barrier. One individual had access to 30 tokens, divided into two separate colours – all of which could be given to the experimenter in exchange for food. Half of these when exchanged resulted in a selfish outcome in which only the individual handing the token received a reward, whereas the other half resulted in an altruistic outcome where both individuals received an equal reward. The individual handing the tokens to the experimenter was rewarded regardless.
If chimpanzees where choosing under a system driven by selfish interests, there should be a preference towards the choice where only the individual in control of the tokens receives a reward, and if the choice was purely random, each token would be expected to be seen 50% of the time. However, it was found that pairs where significantly more likely to share a reward (displaying prosocial behaviour), than choose the selfish option.
Victoria Hornera, J. Devyn Cartera, Malini Suchaka, and Frans B. M. de Waal (2011). Spontaneous prosocial choice by chimpanzees Proceedings of the National Academy of Sciences : 10.1073/pnas.1111088108
Interesting, yet I believe that simply because the experiment shows a greater than 50% chance of each token being used may indeed be due to chance. The sample size is limited. More studies need to be done.
michael potter
August 15, 2011 at 8:54 am
Hello Michael,
It was the comparison of results against control experiments which justified the conclusions, rather than simply “above 50% = Bingo”. The experiment when run using a single individual (with no partner gaining a reward) actually showed a bias in the “selfish” choice***.
However, there are limitations such as the fact only female chimpanzees were used as subjects in the study ect. – but it’s a great start. I’m certain this will be a pioneer to many future studies.
Jamie.
*** http://blogs.scientificamerican.com/primate-diaries/files/2011/08/Figure-2-Prosocial-Choices.jpg.jpg
Jamie Whitehouse
August 15, 2011 at 10:22 am
Actually there are many other factors to consider. would we consider it altruism that the Chimp gave the token under the duress put on him by the other chimp. There is only mesh between them so the other chimp can apply social pressure, which coheres the other chimp to share. Or the chimp might not care which chip he gives to the handler as he gets rewarded regardless. He probably just picks the other color just so he doesn’t have to hear the other chimp whine for a treat.
Marshall PennyPusher
January 15, 2012 at 4:20 am
“The experiment when run using a single individual (with no partner gaining a reward) actually showed a bias in the “selfish” choice***. ”
Well of course the individual would be greedy when alone. However, knowing that another chimp is around, the individual may decide to share..which the study indicates…but not even nearly conclusively…also, we should know the social relationships between the apes..find out if they cooperate more often with realatives and allies..as I suspect is the case…
Mike Potter
February 29, 2012 at 12:29 pm
Hey Mike,
The conclusiveness of this article has already been challenged due to the study not demonstrating perfect prosociality from the subjects (Skoyles, 2011), however Horner et al. (2011) defended this with which I believe a good argument explaining why the results were interpreted the way they are; I’d have a look at these paper if you have access! Links* are at the bottom.
In my opinion, I’m not sure how more a study can more conclusively interpret the presence of spontaneous prosociality. The experiment used standard scientific techniques and statistics, and to contradict this paper you must contradict the very definition of ‘significant’ in a scientific context. In fact, I believe this publication is one of the more conclusive in the literature.
In reply to your statement about the methods/social relationships between the subjects, participants of the experiment were carefully chosen based on different compatibility – a pair with a significantly affiliated relationship, a pair with a significantly negative relationship, and a neutral pair. Despite this (surprisingly), the tendency to be prosocial remained constantly throughout all pair types, indicating the presence of ‘true’ prosociality in opposed to a “You scratch my back, I’ll scratch yours.” scenario which you suggested.
Cheers,
Jamie.
___________________________________
Skoyles, John R. (2011). Chimpanzees make mean-spirited, not prosocial, choices. Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1114006108
* http://www.pnas.org/content/108/42/E835.extract
Horner, Victoria J., Devyn Cartera, Malini Suchaka, and Frans B. M. de Waal (2011). Reply to Skoyles: Misplaced assumptions of perfect human prosociality. Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1114208108
* http://www.pnas.org/content/108/42/E836.extract
Jamie Whitehouse
March 1, 2012 at 8:59 am