(Phys.org)—Researchers from the Max Planck institute have been conducting experiments with chimpanzees that appear to indicate that the apes are not willing to punish other chimps when witnessing them doing something "bad" but will do so if they are the injured party. The team has published their findings in the journal, Proceedings of the National Academy of Sciences.
Punishing people who do wrong is a hallmark of the human race, most often done by people that were not even harmed by the egregious act. Sociologists argue that this is one of the reasons that people have been able to build such large social groups such as villages, towns and cities. But are other animals capable of such behavior, and if so, does it mean they are doing it for the same reasons? While the second question is almost impossible to test, researchers have been searching for examples of the first, and now, the group in Germany has been conducting experiments designed around chimpanzees, to see if they not only will step in when they witness one of their group doing wrong by another, but punish them for it given the chance.
In the experiment, three chimps were placed in an enclosure where they could all see one another, and each was given a role; victim, thief and witness. Initially, the victim was shown how to cause some bit of food to drop down near them. The researchers then pulled on a rope that caused the victim to be able to access the food. At the same time, they also pulled on another rope that allowed the thief to turn the table, causing the food to be taken from the victim. The witness also had a rope and if yanked on, would cause a trapdoor to open taking the food away from the thief.
In testing thirteen chimps, the team found that the witness never once pulled the rope after watching the unjust act, to punish the perpetrator, except when they themselves were the victim, indicating the team says, that chimpanzees simply don't care if another is cheated out of a meal.
Of course this is just one experiment, and while it suggests that chimps aren't the sort to punish some on behalf of others, it doesn't prove that chimps never would given the right set of circumstances. Also just because people do band together to punish offenders, it doesn't mean they do it out of a moral sense, it could be they are simply doing their best to avoid having the same crime committed against them in the future by others.
Explore further: Early exposure to cat urine makes mice less likely to escape from cats
More information: No third-party punishment in chimpanzees, PNAS, Published online before print August 27, 2012, doi: 10.1073/pnas.1203179109
Punishment can help maintain cooperation by deterring free-riding and cheating. Of particular importance in large-scale human societies is third-party punishment in which individuals punish a transgressor or norm violator even when they themselves are not affected. Nonhuman primates and other animals aggress against conspecifics with some regularity, but it is unclear whether this is ever aimed at punishing others for noncooperation, and whether third-party punishment occurs at all. Here we report an experimental study in which one of humans' closest living relatives, chimpanzees (Pan troglodytes), could punish an individual who stole food. Dominants retaliated when their own food was stolen, but they did not punish when the food of third-parties was stolen, even when the victim was related to them. Third-party punishment as a means of enforcing cooperation, as humans do, might therefore be a derived trait in the human lineage.