Chimpanzees Cooperate, Choose Partners

In the ongoing effort to better understand evolution, new studies at the Yerkes National Primate Research Center Field Station have shown that chimpanzees will spontaneously cooperate with a partner, or partners, of their choosing.

Researchers designed the studies to “push the boundaries of cooperation among captive chimpanzees” and allowed the chimpanzees to both participate and choose partners on their own.

“Cooperation among primates has attracted considerable research because of the evolutionary implications that such research has for human behavior and the ubiquity of cooperation among wild primates,” lead author Dr. Malini Suchak said.

The scientists set up a piece of equipment in the chimpanzees’ outdoor enclosure that held a secured tray of treats. Retrieving the treats required one chimpanzee to pull out barrier rods so a partner could slide out the tray and get the treats. Cooperation was crucial because the more adept partner one chose, the more treats one could potentially receive. So, for the 11 un-trained chimpanzees who participated in the study, the freedom to choose a partner was crucial.

“[She] must consider with whom to cooperate, if that individual has been a good partner previously, how much to invest in the partner, what to expect in return and if the cooperation will yield more benefits than solitary effort.”

The chimpanzees successfully cooperated 3,565 times during the 94 different one-hour test sessions. The scientists also found that the cooperation success rate increased over time and decreased when a partner was not present.

According to the scientists, this depicts an extremely evolved and complex level of social interaction.

“Cooperation is often regarded as less puzzling than altruistic behavior, but only in an evolutionary sense,” Dr. Suchak said. “In the moment, cooperation often consists of a series of potentially complex decisions involving a choice of partners. When multiple partners are available, an individual must consider with whom to cooperate, if that individual has been a good partner previously, how much to invest in the partner, what to expect in return and if the cooperation will yield more benefits than solitary effort.”

“That the chimpanzees preferentially approached the apparatus when kin or non-kin of similar rank were present shows a preference for socially tolerant partners,” he added. “And this demonstrates that in the midst of a complex social environment, chimpanzees spontaneously initiate and maintain a high level of cooperative behavior.”

The simple act of letting the chimpanzees participate at their whim and choose their own partners opens up numerous previously unattainable scientific avenues that show the correlation between human and chimpanzee evolutionary behavior.

“Because previous research could only elicit cooperation in a much more controlled setting, we thought more complex, cooperative behavior might have uniquely evolved in humans,” Dr. Suchak said. “This study demonstrates chimpanzees are more cooperative than we realized, and we’ve yet to fully explore the extent of the similarities between chimpanzee and human behavior in this regard.”

Note: The Nonhuman Rights Project does not endorse experimentation on captive animals. However, we do quote the results of these experiments when they help make the case that the animals have a level of sentience, self-awareness, and, in some cases, a theory of mind that demonstrates that we should not keep them in captivity in the first place.