Scharlette Holdman was a "mitigation specialist" working in California.
Her job was to work with defence lawyers on murder cases.
Not to get the defendant acquitted – she was involved after guilt was already accepted.
It was her job to avoid the death penalty.
She worked in the field for 40 years and pretty much invented it.
The Supreme Court reinstated the death penalty in 1976, but it was compulsory to consider "compassionate or mitigating factors stemming from the diverse frailties of mankind".
This was the territory where Holdman worked.
At the height of her career, in the mid-1990s, 300 people a year were being executed.
By the time she retired, 20 years later, she helped get that down by 90%, to just 30.
In some ways, her work was similar to ours – she must persuade people to buy her argument against the competition’s.
My favourite case of hers took place in California.
Holdman had just 30 days to help a defendant avoid the death penalty.
The man was a schizophrenic, divorced from reality, and had an IQ of just 58.
He wrote secret messages on toilet paper, rolled them in faeces, and stuck them in his hair.
She argued that he couldn’t understand the consequences of his actions.
But the prosecution said that he could – the main thrust of their argument was that he was perfectly sane because he could beat their psychiatrist at noughts and crosses.
They contended that this proved he understood his actions.
What Holdman did next was a great example of a convincing demonstration.
She remembered that when she was a child, her parents took her to a state fair where a chicken playing noughts and crosses was a big attraction.
She needed to find a chicken that could beat the prosecution’s psychiatrist at noughts and crosses.
She immediately began phoning carnivals and fairs across the country.
She didn’t want a goose or a duck, they were too aggressive – it must be a chicken.
A chicken was more ridiculous and would make the point better.
She found one in Wyoming, she found one in Arkansas, but in each case it was too far for the chicken to travel.
Eventually she found one in San Francisco, performing on the boardwalk.
She was convinced that, if the chicken could beat the prosecution’s psychiatrist, it would prove that being good at noughts and crosses didn’t mean you could understand the consequences of your actions.
Consequently, her client couldn’t be proved to have understood his actions, so the death penalty would have to be commuted to life imprisonment.
What I love is that’s exactly the sort of powerful demonstration the best advertising consists of: it’s striking, it’s funny, it’s convincing, it’s memorable.
There was one problem: the judge wouldn’t allow it, it ridiculed the prosecution’s case, he said it would "degrade the dignity of the court".
Holdman said: "The dignity of the court is already degraded by trying to execute a mentally retarded, mentally ill person."
And, even without being allowed, that powerful demonstration stayed in the court’s mind.
Even without seeing the full demonstration, her argument swayed opinion so much that, on appeal, the penalty was commuted to life imprisonment.
And, shortly after that, the Supreme Court changed the law so that a person with that level of mental illness couldn’t be executed.
That’s a great lesson for us: no logical argument is as convincing as a powerful, funny, memorable demonstration.
Dave Trott is the author of Creative Blindness and How to Cure It, Creative Mischief, Predatory Thinking and One Plus One Equals Three