In 1842, the Illinois State Bank’s banknotes had plummeted in value.

So the state auditor, James Shield, supported a bill to require all debts to the state (taxes, school fees, etc) to be paid only in gold and silver.

This meant the state wouldn’t accept banknotes which it had itself issued.

This outraged Abraham Lincoln, who was then just a lawyer.

He wrote a letter to the newspaper pretending to be a poor farmer’s wife, called Rebecca, asking where she could get gold and silver, in it he called Shields “a fool and a liar”.

Lincoln’s fiancée, Mary Todd, detested Shields and wrote letters under the name Cathleen, also criticising him, but for being crude and ugly.

Shields was told that Lincoln had written all the letters, and demanded an apology.

Lincoln agreed to apologise for the first letter but not the subsequent ones.

This wasn’t good enough for Shields who challenged him to a duel.

This is where Lincoln used choice architecture.

As the person being challenged, Lincoln had the choice of weapons.

Shields was an excellent shot so Lincoln chose to use the longest cavalry broadswords.

Lincoln was 6’ 4’’, Shields was shorter at 5’ 9’’, this gave Lincoln a reach advantage, which he increased by specifying a long plank be placed between them, which neither must come closer than a yard to.

This meant Shields would struggle to reach Lincoln, but Lincoln could easily reach Shields.

Before the duel, Lincoln reached across and cut a branch from above Shields’ head.

Shields saw sense and accepted Lincoln’s apology for the first letter and agreed that Lincoln hadn’t written the subsequent ones.

So Lincoln had allowed Shields to choose the option Lincoln wanted.

Choice architecture is simply that.

At GGT we had a German umbrella manufacturer as a client, Knirps (pronounced K-nirps).

The benefit of their umbrellas was they’d bend but not break, but the problem was getting their name known in the UK.

So we decided to film a man in a carwash with a Knirps umbrella, as it turned inside-out he just popped it back the right way.

But we also needed a mnemonic to make the name stand out, so I wrote: “YOU CAN BREAK A BROLLEY, BUT YOU CAN’T K-NACKER A K-NIRPS”

Obviously, the television censors objected.

They wanted proof of the umbrella’s strength, and they also thought ‘knacker’ was rude.

So I went to Foyles and looked through 4 dictionaries, one said ‘knackers’ was slang for testicles, but the 3 others said ‘knacker’s yard’ was a place where old horses went to be turned into glue.

So I took the 3 dictionaries that said what I wanted along to the censors, to prove that knacker wasn’t a rude word.

Then we invited them along to see the ad being filmed, to prove we weren’t cheating (we had the actor rehearse all the previous day to make sure he got it right).

And that’s how we helped the censors to make the choice we wanted.

That’s what choice architecture is.

You don’t tell anyone what to do, but you set it up so they make the right choice.

Chris Powell, the MD of BMP, once said to me, “We are like barristers presenting an argument in court, we don’t lie, we simply present the facts that support our case in the most persuasive way.”

Or, as the politician Daniel Vare said, “Diplomacy is the art of letting the other fellow have it your way.”