Persuasion Trigger Five:
In essence, the scarcity principle says we value what is scarce. When we discover that something is scarce or may be unavailable, one of our first thoughts is that it must also be valuable.
Potatoes haven't always been a popular food staple: In the late 1700s, the French associated potatoes with leprosy; the Germans considered potatoes were only good as cattle fodder; the Russian peasants believed they were poisonous.
It took the guile of Catherine the Great, the Empress of Russia, to turn this negative perception around. She ordered her men to enclose the potato fields with high fences. Her soldiers then posted large notices throughout the countryside warning the populace not to steal potatoes.
It was a brilliant psychological ploy. As soon as the potatoes became unavailable, the scarcity principle took hold and the popularity of potatoes suddenly soared.