How a plan to kill cobras created more cobras

A short history of solutions that bite back.

The story goes like this. In colonial India, the British rulers were worried about venomous cobras in Delhi.

So they offered a bounty. Bring in a dead cobra, get paid. Simple. Let the public help solve the problem.

At first it worked. People brought in dead cobras. The streets got a little safer.

Then some enterprising locals noticed something. If a dead cobra is worth money, why hunt them? Why not breed them?

People started farming cobras to collect the bounty.

When the government found out, they scrapped the program. The breeders, now stuck with worthless snakes, set them loose.

Delhi ended up with more cobras than it started with.

This is the cobra effect, and it is not just a colorful old tale.

In Hanoi under French rule, officials paid people for rat tails to fight a rat infestation. Soon they were finding tailless rats running through the streets. People had cut the tails and freed the rats to breed more.

The pattern is always the same. A reasonable solution creates an incentive nobody planned for, and the incentive quietly eats the solution.

It happens in offices that reward staff for closing tickets, and suddenly get a flood of tickets closed badly. It happens in schools that teach only to the test. It happens any time you measure one thing and forget that people will optimize for exactly that.

Here is the uncomfortable part. The cobra effect does not need villains.

Everyone in the cobra story was being rational. They just followed the incentive they were handed.

So when you see a problem and reach for the obvious fix, pause on one question. What will people actually do once this rule exists?

The answer is rarely the one you intended.

The road to hell is paved with good intentions.

An old proverb.