Posted: June 11, 2012 | Author: John Ford

Many of you may have heard the myth of the monkey/ladder/water-spray experiment, which put like that sounds rather odd. What not so many people know is that said experiment is not a myth. In 1967, it was conducted by G R Stephenson, under the title ‘Cultural acquisition of a specific learned response among rhesus monkeys’ .

The experiment ran as follows. Stephenson collected 5 monkeys and locked them in a cage. From the ceiling of the cage, he hung a bunch of bananas, which could only be accessed by a step ladder leading to them, which the monkeys could climb. There was, however, a catch. Every time a monkey started to climb the step ladder, that monkey was sprayed with ice-cold water. Not only that, but the other 4 monkeys were sprayed with cold water as well. This was repeated every time a monkey attempted to climb the ladder until the monkeys became conditioned: no monkey must climb the step ladder.

Stephenson then replaced one of the monkeys with a newcomer. Just one. Fairly quickly, the newcomer spotted the bananas and went for the step ladder. But the other monkeys – knowing the drill by now – quickly rushed to stop the newcomer, screaming and snarling at him and even scratching him. Without any intervention by the scientists – with no water even being sprayed on him – the new monkey immediately became conditioned as well.

Stephenson then went on to replace the other monkeys in turn. Remarkably, every time a new monkey was added and went for the step ladder, all the monkeys that had been conditioned rushed to stop him, screaming, snarling and scratching. Even those who had never been sprayed before joined those who had in beating the new monkey.

Eventually all of the monkeys had been replaced. None of them had ever been sprayed with cold water, yet none of them dared to climb the ladder to get the banana. When the final new monkey was added, they rushed to uphold the rules as before.

The new monkey would be justified in questioning this behaviour. And what could the other monkeys say? They had never been sprayed. Yet if they were to answer, they would probably say something like this:

“That’s just the way we do things here. It’s just how life is.”

That sounds familiar…

Initially, the learned response not to go up the step ladder made sense. But soon it was rendered redundant – the scientists had not sprayed any of them since the first of the new monkeys was added – yet it continued to be upheld…

Human beings are also (and even more so) creatures of habit. We are used to going through life obeying social norms or customs, that were adopted for a reason that must have been important at some point in time. But how many of those are outdated and should be changed or  be improved on? Fortunately we have the capacity for change. Although as the new monkeys found out to their cost, it is not always easy to fly in the face of popular beliefs.

Nonetheless, this experiment highlights the remarkable power of behavioural conditioning, mob mentality and the importance of questioning social and cultural beliefs and customs.