2.5. Will Press Lever for Food
Posted on 7 November 2019
With the dawn of the 20th century, a new wave of thinking arose to link the mind to the body.
Understanding how to create a reflexive action from a dog is one thing, but American scientist BF Skinner wants to develop Pavlov’s theory to see if there was more to it then a reflex. Pavlov was using just a single reflex. Skinner wants to use more.
Born in 1904, Skinner devotes his scientific career to breaking the boundaries of what could be achieved through Classical Conditioning. Skinner wonders, is it possible to link a set of reflexive behaviours together to create a desired response?
He uses his imagination to go beyond simply making a dog salivate.
Maybe, he thinks, you could make the dog rollover, stand on two legs and jump through a hoop just by giving it associations with rewards.
Naturally Skinner wants to try this on humans, but at first he takes something far more manageable than the human mind, he chooses rats.
The Box, the Lever and the Food
Imagine You as a rat with the size of a brain.
Not too difficult is it?
You are in a box with a lever and a feeding chute.
Food, in the form of peanuts, is so tantalizingly only a paw-press away.
With your tiny pink rat’s paw, every time you push the lever a peanut comes from a chute.
You’re tapping away on the lever for whenever you want peanuts and you have water on tap.
You’re as happy as a rat could be.
However, one day you press the lever and nothing happens. In frantic confusion you press the lever not once but twice and still nothing.
What is happening?
Could it be that all the peanuts have run out and you could be left starving?
Now in desperation you press the lever again not once, but three times, and in a sheer moment of joy you see a peanut coming towards you down the chute.
What is being tested?
As a rat you have no idea why it now takes three presses instead of one, but as a human can you work it out?
Rewarding Fixed Behaviour
Skinner was testing behaviour linked to reward. The test was to see if it would it be possible to reward a behaviour and repeat it so many times that the subject continually repeats the behaviour at will.
Skinner was using Classical Conditioning to teach the rats that a task had to be performed in order to get the reward.
By making the rats repeat the action of pressing the lever three times, Skinner was reinforcing the rats’ learning that lever pressing would always lead to a reward.
The behaviour is fixed because pressing the lever three times would always result in a reward.
And by pressing the lever three times instead of one, the fixed behaviour from the rat is three times as strong.
Rewarding Random Behaviour
Next, Skinner put rats in a series of boxes with several levers on the floor.
When the rats stood on a lever sometimes a peanut was released.
Very soon the rats learned that by continually pressing the levers they would be rewarded by food.
However, Skinner designed the experiment so that peanuts would be randomly released. Sometimes the rats had to put their tiny pink paws on the lever once, twice or maybe three times.
As a rat, you understand that the lever needs to be pressed several times. But, understanding that each time the number of presses randomly changes is beyond your rat’s brain.
The reward is random and the Classical Conditioning is now stronger than ever.
You just keep pressing the lever.
Skinner has taught you well.
You, poor ratty, comply every time.
Image from colbypearce.net
