Since 2011 or even earlier, I have been seeing images, articles, and storytellers all recounting of a “banana experiment.” This experiment is supposedly the groundbreaking proof that our sometimes rabid defense of power structures and tradition are actually evolutionarily grounded.

Before I explain what the truth behind the story is, I suppose I should probably tell the story. But since I am well aware that people prefer images to words, I will let an image tell the story:


Although this little story seems to clearly explain a piece of human evolutionary history, the fact is that this story never happened. I can understand your confusion, after all: it has been presented as fact in a since-redacted Psychology Today article by Michael Michalko in 2011 and by TED guest Eddie Oblong in a speech at Jive in 2013. I recently saw a friend of mine post the story and get over 1,000 shares on Facebook. This is a misunderstanding that is still alive and well.

Firstly, it wasn’t “scientists” but G.R Stephanson, and the year was 1967. There was no group of monkeys, and the “object” was not on a ladder, nor was it likely a banana. The monkeys (actually chimpanzees) were placed in pairs of a “normal” monkey with either a monkey that had been punished with an air-blast (not water) for trying to touch the object, or with another normal monkey. The study found that conditioned monkeys would show “threat facial expressions while in a fear posture” when the other monkey went for the object, and in one case a trained (conditioned) monkey held back an untrained monkey from touching the object. There were no groups of five, and conditioning also did not take place in a group setting.

To be fair: the “trained” chimp’s response reduced the use of the object by the untrained chimps. If the monkeys had seen another chimp be punished for trying to touch the object, there is little doubt that they would also avoid touching it: this is a trait they share with us humans (called Bandura’s observational learning). By being punished for trying to do it, the chimps underwent operant conditioning, which drastically reduces their odds of trying it again. But, we have to keep in mind that this influences the probability of an action, and in no way does it necessarily mean “trained” individuals will actively attack others who try to do the same.

Certainly, the examples of the use of excessive force and violence by police against protestors throughout history give us a clear look at “banana experiment” type conditioning in action. But, in the face of this violence, we saw people continue to do what they knew was right. Nelson Mandela did not get beat and thrown in jail to simply give up and tell others to step back, but instead he conquered his own fear and saw his struggle through to the end.


Although the point the story is trying to make, that we can be conditioned based on the consequences of actions which affect both our likelihood to do it and our reaction to others trying to do the same, is a valid one: it is important to explain the roots. It is important to talk about conditioning, both cognitive and behavioral, which influences how we act, how we perceive, and how we deal with others. Only by being aware of how plastic our habits and perceptions are, can we hope to change them on both a small and large-scale. We certainly aren’t helping enlighten ourselves or others by spreading misinformation, though.