This is Hidden Brain, I'm Shankar Vitaantham.

We like stories about leaders who have big ideas,

who define the odds and pursue their goals with messianic purpose.

Think of Winston Churchill in World War II,

or Abraham Lincoln during the Civil War.

But what happens when a leader's vision is the wrong one?

How do we think about people who dream big,

only to invite disaster?

At such times, we might prefer a more cautious style,

someone who plays the odds.

Those leaders might not score historic triumphs,

but they rarely cause catastrophes.

Thousands of years ago, the Greek poet Arkelicus summed up this idea.

He said, the fox knows many things,

but the hedgehog knows one big thing.

That has been, that parable has been the subject of much debate over the last

2500 years, what exactly Arkelicus meant.

This is a psychologist Phil Tetlock.

Various people have offered various interpretations.

Some people coming out on the side of the hedgehog,

saying the hedgehog will trump the fox,

and other people saying no, it really means the fox is going to do better.

...