It was called the trial of the century. In 1995 OJ Simpson stood trial for the murder of his ex-wife, Nicole Simpson-Brown, and her friend, Ron Goldman.
On 13 June, seven months into the trial, the prosecution led by Marcia Clark presented a pair of blood-stained gloves to the jury. One had been found at the murder scene, the other at Simpson’s mansion.
After showing the gloves to the jury the prosecution instructed Simpson to try them on. Simpson struggled with the gloves, eventually squeezing his hands in.
The two sides offered alternate explanations for the tight fit. The prosecution argued that the latex gloves Simpson was wearing to avoid cross-conatmination were causing the squeeze.
In contrast, the defence suggested that the gloves didn’t fit because they weren’t Simpson’s – they had been placed at the scene by a corrupt cop.
The defence counsel, Johnnie Cochran, summed up his argument: "If it doesn’t fit, you must acquit".
It was the most memorable line of the 11-month trial.
A line that became, in NBC’s words, an "enduring motto in pop culture".
A line that was still reverberating in the jurors’ minds when, on 2 October, they returned a not guilty verdict. There were other reasons for the acquittal but Cochrane’s rhyme was an important one.
The appliance of science
But why is rhyme such a powerful rhetorical technique?
There are two main reasons: perceived accuracy and memorability.
First, let’s discuss accuracy. Matthew McGlone and Jessica Tofighbakhsh, in the aptly named paper, "Birds of a feather flock conjointly (?)", investigated the role of rhyme in conveying accuracy.
In 1999 the academics from Lafayette College asked 60 students to rate the accuracy of 30 aphorisms on a nine-point scale.
The twist in the study was that the students received slightly modified lists. Sometimes the sayings rhymed, while others were tweaked so they didn’t.
In both cases the meaning of the saying was consistent, only the rhyme changed.
For example, one group heard that, "What sobriety conceals, alcohol reveals", while the remainder learned that, "What sobriety conceals, alcohol unmasks."
Overall, the rhyming sayings were rated as 22% more accurate than non-rhyming ones. The academics attributed the greater influence to the "enhanced processing fluency" of the rhymes.
Ironically, that’s academic jargon for being easier to understand. The participants conflated ease of understanding with truthfulness.
We remember rhyme for a long time
Accuracy isn’t the only reason why rhymes are effective. Ads need to be memorable, and rhyming helps here too.
My colleague, Alex Thompson, and I adapted McGlone and Tofighbakhsh’s test to quantify the effect of rhyme on memorability.
One morning, we showed colleagues a list of 10 statements, half of which rhymed and half that didn’t. They had five minutes to read the list. We then asked them to return at the end of the day and list as many of the phrases as possible.
The results were conclusive. Across a week 36 people read 180 rhyming statements and 180 non-rhyming ones. They were twice as likely to remember the rhyming ones. 29% of the rhyming statements were recalled compared to only 14% of the non-rhyming ones.
The effect of rhyme as a powerful device is not limited to the artificial settings of a lab experiment. Much of our folk wisdom rhymes, from ‘an apple a day keeps the doctor away’ to ‘a friend in need is a friend indeed’. These phrases often stay with us from childhood - lodged in our minds by the rhyme.
Similarly, there’s a long history of successfully using rhymes in ads. In 1930s Lord and Thomas coined the strapline, "Don’t be vague, ask for Haig".
In the 50s there was "Oxo gives a meal man appeal".
In the 60s there were classics like "Easy peasy lemon squeezy", "Beanz meanz Heinz" and "Winston tastes good like a cigarette should".
In the 70s one of the most successful lines was "For mash get smash" and, in the 90s, Pringles coined "Once you pop you can’t stop".
But what about the last decade? Stop for a moment and try to think of a major campaign that has used rhyme? It’s much harder, isn’t it?
This isn’t a case of selective memory. Alex Boyd and I catalogued hundreds of ads in copies of The Times and The Sun stretching back to 1977. There was a clear pattern.
In the last decade, the number of ads with a prominent rhyme has halved; since 2007 about 4% of print ads included a rhyme compared to 10% in the previous years. Rhymes have fallen out of fashion.
Rhyme isn’t past its prime
Why are advertisers avoiding rhyme? There are two reasons.
First, advertisers have fallen for the fallacy that consumers have fundamentally changed in the last few years. To some this damns a tactic that was successful as far back as the 1930s. But rejecting rhyme as out of date is illogical when the supporting experiments are recent, not relics of the yesteryear.
Second, rhyme doesn’t fit with marketers’ motivations. Makers of ads – creatives, planners, clients –want their peers’ admiration. That’s only natural.
But what gains us professional kudos is not the same as what makes for an effective ad.
Our peers, other experts in advertising, are often impressed by sophisticated and clever techniques. This leads to simple solutions, like rhyme, being derided as simplistic.
But complex solutions are not necessarily effective. This distinction was crucial in the OJ Simpson trial. Marcia Clark, the prosecutor, tried to wow the jury with the sheer volume of evidence and her impressive intellect.
Cochran, on the other hand, defended OJ in simple, yet powerful, terms, using vivid metaphors and memorable rhymes.
In ads, like trials, simple solutions succeed.
Richard Shotton is deputy head of evidence of Manning Gottlieb OMD