The way it’s always been done
- Start with a cage containing five apes. In the cage, hang a banana on a string and put stairs under it. Before long, an ape will go to the stairs and start to climb towards the banana.
- As soon as the ape touches the stairs, spray all the apes with cold water. After a while, another ape makes an attempt with the same result - all the apes are sprayed with cold water.
- Turn off the cold water. If, later, another ape tries to climb the stairs, the other apes will try to prevent it even though no water sprays at them.
- Now, remove one ape from the cage and replace it with a new one. The new ape sees the banana and wants to climb the stairs. To his horror, all of the apes attack him. After another attempt and attack, he knows that if he tries to climb the stairs, he will be assaulted.
- Next, remove another of the original five apes and replace it with a new one. The newcomer goes to the stairs and is attacked. The newcomer takes part in the punishment with enthusiasm.
- Again, replace a third original ape with a new one. The new one makes it to the stairs and is attacked as well. Two of the four apes that beat him have no idea why they were not permitted to climb the stairs, or why they are participating in the beating of the newest ape.
- After replacing the fourth and fifth original apes, all the apes which have been sprayed with cold water have been replaced.
Nevertheless, no ape ever again approaches the stairs. Why not?
BECAUSE that’s the way it’s always been done around here.
Did the monkey banana and water spray experiment ever take place?
There is no evidence that that this experiment ever took place. An experiment was done in 1966 that involved pairs of monkeys but the results are irrelevant to the above story. Some of the results actually contradict the story: in some pairs, the new monkey behaved so fearlessly around the object that the first monkey learned to lose their fear of it altogether.
Sources: Stephenson, G. R. (1967). Cultural acquisition of a specific learned response among rhesus monkeys. In: Starek, D., Schneider, R., and Kuhn, H. J. (eds.), Progress in Primatology, Stuttgart: Fischer, pp. 279-288.
Mentioned in: Galef, B. G., Jr. (1976). Social Transmission of Acquired Behavior: A Discussion of Tradition and Social Learning in Vertebrates. In: Rosenblatt, J.S., Hinde, R.A., Shaw, E. and Beer, C. (eds.), Advances in the study of behavior, Vol. 6, New York: Academic Press, pp. 87-88: