Concept
Rhyme-as-Reason Effect
language persuasion advertising
A statement is judged as more accurate and more believable when it rhymes than when an equivalent non-rhyming version conveys the identical meaning — people mistake the ease of processing a rhyme for evidence of its truth (see Lafayette Rhyme-as-Reason Study).
Despite the effect being well-evidenced, Richard Shotton notes that rhyme use in UK print advertising has fallen over recent decades (from roughly 10% to 4% of ads by his and Alex Boyd's analysis of the Times and Sun archives). He attributes part of the decline to rhyme picking up connotations of being "tacky" or "cheap," but also to plain industry mimicry — once few competitors use rhyme, its absence starts to look like the norm, discouraging its use further regardless of the underlying evidence.
A fuller, 2000-era demonstration (Episode 145). Matthew McGlone and Jessica Tofighbakhsh's foundational study (also called the key heuristic) gave participants fake proverbs, some rhyming ("woes unite foes"), some not ("woes unite enemies") — synonymous in meaning, differing only in whether the final words rhymed. Rhyming versions were rated 17% more believable and accurate. When directly asked whether rhyme influenced their rating, nearly every participant denied it — people don't believe rhyme sways them, even as it measurably does (see McGlone Tofighbakhsh Rhyme-as-Reason Study). Rhyming brand slogans for two fictitious products were separately rated 22% more trustworthy and made participants 10% more willing to try the brand than non-rhyming versions of the same slogans, in a 2013 Norwegian study (see Oslo Rhyming-Slogan Trust Study). Shotton's own pilot study found participants were roughly twice as likely to recall a rhyming proverb eight hours later than a non-rhyming one — rhyme boosts both believability and memorability.
Alliteration produces a smaller version of the same effect. A 2022 study by Hamish Bromley, Joanna Stanley and Richard Shotton rewrote ten alliterating proverbs into non-alliterating equivalents of identical meaning ("sleep softens sorrows" vs. "sleep lessens worries"). Alliterating versions were rated 7% more believable and 22% more memorable (see Bromley Stanley Shotton Alliteration Study).
Why the decline, despite the evidence? Shotton offers two explanations: rhyme doesn't read as sophisticated, so agency staff avoid it to signal their own expertise rather than optimize for effectiveness; and (citing Nassim Nicholas Taleb) consultants without genuine Skin in the Game in a product's performance are incentivized toward complexity, since complexity justifies their fees more convincingly than a simple, provably effective rhyme.
A rhyme's role in one of the 20th century's most famous verdicts (Episode 116). Daniel Pink cites OJ Simpson's defense attorney closing with "if it doesn't fit, you must acquit" — a line whose rhyme, not just its logic, plausibly made it more memorable and persuasive to the jury (see OJ Simpson Glove Rhyme Verdict Case (1995)).
Discussed in
- Episode 5 — 5- The science behind distinctive advertising
- Episode 116 — How to get a raise -according to Dan Pink (OJ Simpson trial)
- Episode 145 — 145-why-ads-that-rhyme-stand-the-test-of-time
- Episode 188 — 188-how-adverts-use-psychology-to-win-you-over (re-cited, conflates McGlone's figures with Lafayette's examples)
- Episode 190 — 190-how-to-give-an-election-winning-speech (re-cited, adds Bromley/Stanley/Shotton alliteration study)