This is Hidden Brain, I'm Shankar Vedanta.

There's something about the prospect of getting a good deal that does curious things to our minds.

Imagine for example that you need to buy a new bed spread.

You're in luck because there's a sale happening right now at a store near your house.

Usually, the bed spreads are priced according to size,

a double cost 200, a queen cost 250, and a king size bed spread cost 300 dollars.

But on this day, all the bed spreads are on sale for the low, low price of 150 dollars.

You have a double bed.

The question is, what size bed spread do you buy?

The behavioral economist Richard Thaler once told me about a friend who faced just this situation.

She had a double bed.

Again, the usual price was 200.

The sale price was 150.

She was ecstatic about the idea of saving 50 dollars.

But then she got to thinking about how she could save even more.

If she bought the queen, she'd save 100 dollars.

And if she bought a king size bed spread, she would save a whopping 150 dollars.

You can guess where this is headed.

She snapped up the best deal, went home with the king, which meant of course that the enormous bed spread

now draped onto the floor.

Now, maybe you're thinking, I'd never do that.

I'd buy the bed spread that fit my bed.

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