I saw a great card trick recently.

Strangely, it was during a lecture on how the brain works.

There was an audience of about a hundred people.

The lecturer laid out 5 cards.

King of Hearts

Queen of Clubs

King of Spades

Queen of Diamonds

Jack of Clubs.

He said to us “I want each of you to pick a card and don’t tell anyone what it is.”

I picked the Queen of Diamonds.

He said “I want you to concentrate very hard on the card you’ve just picked.”

So I did.

Then he scooped up all the five cards.

He said, “I’m going to put the cards back out, but the card you picked won’t be among them.”

And he laid out four cards.

Queen of Hearts

King of Clubs

Queen of Spades

Jack of Diamonds.

And my card wasn’t there.

He’d left out the Queen of Diamonds.

I thought, that’s pretty amazing.

He said “Raise your hand if I left your card out.”

Everyone raised their hand.

This was really amazing.

It meant we’d all picked exactly the same card.

But how did he get us all to pick the Queen of Diamonds?

Somehow he’d laid the cards in such a way that we all chose the card he wanted.

Even though we were trying not to.

He said “Would you like me to tell you how it works?”

Everyone said yes.

He pointed to a member of the audience.

He said “What was your card?”

She said “Queen of Clubs”

There was a murmur from the audience.

He pointed to another person.

He said, “What was the card you picked?”

She said “King of Spades”.

The audience began mumbling.

He said “Anyone else whose card wasn’t there, shout it out.”

Someone shouted “The King of Hearts”.

Someone else shouted “The Jack of Clubs”.

Someone shouted “The Queen of Diamonds”

He said “That, Ladies and Gentlemen, is the trick.”

Everyone went quiet.

He said “None of your cards were there, not one.”

Gradually it dawned on us.

He said “I replaced all the cards with cards that were very similar. But of course no one memorised all the other cards.

Each of you just concentrated on your own card.

So that when a similar looking set of cards came back, all you noticed was that your card wasn’t there.

You didn’t notice that every single card had been changed.”

And that’s how the human mind works.

It takes a little piece of information and assumes that’s all the information there is.

Isn’t that the way we do our job?

Research, strategies, insights, rules.

From the little part we know, we assume we know everything.

And we make observations, insights, rules, based on the little bit we do know.

The little bit that we think is everything.

We’ve got closed minds.

And however much the technology changes, the human mind doesn’t.


In the 5th century BC, the Chinese sage Lao Tzu said, “The wise man knows he doesn’t know. The fool doesn’t know he doesn’t know.”