This is Hidden Brain, I'm Shankar Vedantam.

We begin today with a tale of a man known as a miser.

A man so unmoved by the plight of others,

that he has become synonymous with greed and selfishness.

His name was Ebenezer Scrooge.

A Mr. Scrooge I presume, indeed you do, sir.

Scrooge, of course, was a character and child's Dickens' famous story,

a Christmas Carol.

And yes, I know it's not Christmas, but stay with me a moment.

I'm about to.

In this 1984 film version of the story,

Scrooge refuses to give money to a charity that's helping the poor.

My tax is helped to support the public institutions which I have mentioned,

and they cost enough.

Those who are badly off must go there.

Many can't go there, and many would rather die.

If they would rather die, perhaps they'd better do so.

And decrease the surplus population.

Scrooge is visited one night by some unwelcome guests

who push him to question his outlook.

Their ghosts.

The first two remind him about his past and present

...