Mankind’s bipolar ability to act out of both altruism and spite is not shared by some of our closest evolutionary relatives, according to a study published today in the journal Nature Communications that reveals how chimps simply don’t give a damn if they help or hinder others.
The evolutionary roots of our complex social behavior has kept primatologists occupied for years, and while some researchers have found evidence of selfless generosity among chimps, this latest work appears to dispel this notion. The study authors therefore claim that any pro-social behavior seen in prior studies may have simply been an “illusion”, as the design of these experiments may have inadvertently prompted the chimps into helping each other out.
Thirteen chimpanzees were given the opportunity to release a peg that would either begin or halt the flow of food to a visible partner in an adjoining room. During the first round of testing, the chimps were just as likely to release the peg in both scenarios, regardless of whether it helped their counterpart access food or blocked their supply.
In order to confirm that the animals fully understood the consequences of their actions, the researchers then allowed the chimps to enter the feeding room after releasing the peg, so that they themselves could access the food. On nearly every trial, they released the peg when it initiated the flow of food, but never when it blocked the flow, indicating that they grasped what was going on.
After this round of training, the researchers repeated the experiment, and found that the chimps were still just as likely to help their partners as hinder them, leading the study authors to conclude that the “chimpanzees did not take into account the social consequences of their actions, even after having learned personally about the outcomes of their actions.”
In a statement, study co-author Claudio Tennie explained that “given that the participants were just as likely to prevent access to food as they were to permit access, chimpanzees are no more altruistic than they are spiteful. Even after they demonstrated a clear understanding of the consequences of their actions, they remained indifferent to any effects these actions may have on others.”