I wrote about Skinner’s Rat some months back. We discussed it during our recent Value Investing Mastery Classes and here is a follow up to explain why it is so difficult to remain invested for the long run.

In a cage there are some rats. The cage has a lever that the rats can press. The experimenters want rats to learn the lever pressing behaviour, and to do that they have programmed food as reward for the rats.

For some cages, the food is dispersed at a fixed ratio. Every press of the lever brings about a pallet of food. The rats learn it quickly, and they like it very much. Every time they are hungry they would go for lever and they will be rewarded with food. The lever pressing behaviour is reinforced and learned.

In other cages, the food is dispersed at a variable ratio schedule. Sometimes the …