O.J. Simpson was in a hole. His estranged wife Nicole had been murdered. He had been apprehended by the police in suspicious circumstances after a bizarre slow-motion car chase.

There was a mountain of evidence pointing towards O.J. as a jealous, abusive husband with the motive and means to kill Nicole and her friend, Ronald Goldman, who had had the misfortune to call in at Nicole’s home while she was being attacked.

So O.J. Simpson was brought to trial in one of the most intensely followed media spectacles of the 1990s. Evidence included a trail of Simpson’s blood and eyewitness accounts of his previous violence towards Nicole.

But O.J. had a couple of aces up his sleeve.

The first was the deep-rooted distrust between members of Los Angeles’ black community and the L.A. Police Department. A jury with plenty of African Americans in its ranks would look skeptically at any evidence presented by the cops.

The second ace was Johnnie Cochran.

A lawyer with a stellar record, Cochran knew how to tell a compelling story. All the DNA and eyewitness evidence in the world would count for nothing if Cochran could persuade the jury there was something fishy about it. He only had to furnish them with grounds for reasonable doubt and O.J. would be home free.

Cochran and his fellow defence lawyers played their hand with matchless skill. First, they managed to expose Mark Fuhrman, the police officer who had been among the first on the crime scene, as a bone-deep racist. This was enough to taint the police evidence in the eyes of many African-American residents of L.A., who remembered with rage episodes such as Rodney King’s beating by LAPD officers.

But the masterstroke came when Cochran invited Simpson to put on the glove found at the crime scene. The defendant was able to show that the glove was not a comfortable fit with his athritic, ex-football player’s paw.

And so, when the time came to sum up the case for the defence, Cochran had a message for the jury: “If the glove doesn’t fit, you must acquit.”

A rhyme. A jingle. An earworm to smuggle into the jury room, and let do its work.

Sure enough, the jury decided that the prosecution hadn’t proved its case beyond reasonable doubt. You can imagine the 12 men and women of the jury rehashing all the evidence they had seen and heard. The drama of the glove that didn’t fit would have been part of that discussion. And if any of the jury members wanted to dismiss this circumstantial evidence, they had a handy mantra. “If the glove doesn’t fit, you must acquit.”

O.J. was acquitted.

This is not a post about the morality of trial by jury or the guilt of O.J. Simpson. It’s a reminder that the human mind loves clear narratives that can be conveyed in a rhyming couplet. Give people a rational argument, and they may or may not remember it. Give them a rhyme and they’ll repeat it forever afterwards.

Want more proof? Very well.

Every New Zealander of a certain age can sing a little song that ran for less than 30 seconds during a TV ad during the early 1970s. Here’s a hint:

“Hugo said ‘You go!’

And I said ‘No you go!’…”

The power of a rhyme surpasses all reason.