There’s plenty of research proving the power of positive claims. Since the 1950s studies have repeatedly demonstrated that increasing the number of positive statements about something increases positive impressions of it – the so-called set size effect. This seems logical enough. The better something is, the more good things there are to say about it – so the more good things said about something, the better it must be.
The problem is these studies were conducted by psychologists and sociologists, perceived by their test subject as having no ulterior motives. In other words, the studies only measured the impact of positive claims in messaging seen by the audience as descriptive rather than persuasive. It turns out that when readers suspect you’re trying to sell them on something, a whole new scale of appeal kicks in.
Marketing and behavioural science experts Suzanne Shu and Kurt Karlson conducted an experiment in which subjects were exposed to messaging clearly intended to influence them – but in a variety of ways. Four scenarios related to product or service advertising: cereal packaging, a restaurant billboard, an ad for shampoo and a sign at an ice cream store. But two other scenarios added other ulterior motives – a woman rationalising hooking up with an ex-boyfriend, and a politician speaking to a group of students.
The messages were presented with from one to six positive claims to support them. Up to a certain point adding positive information did increase positive impressions of the object, consistent with the set size effect. But beyond that point, additional information actually led to a drop in the favourable impression as scepticism about motivation began undermining the credibility of the narrative. In other words, after the optimal point was reached more persuasion not only became less effective, it became counterproductive.
When your writing is meant to persuade readers (which is always) you will be tempted to anticipate all possible counter-arguments, dispel any potential doubts, or answer every conceivable question by brandishing all the positives at your disposal – good evidence, good reasons, good outcomes. After all, the one thing you leave out might turn out to have been the tipping point, the decisive factor in selling your message. But it turns out that all the information is too much information. If you want to influence readers, then part of knowing what to write is knowing what not to write.
And what is the optimal number of claims, the Goldilocks zone where the positives are neither too few to be persuasive nor too many to be plausible? According to the outcomes of the study – three. Target appeal increased with each additional positive statement up to three, but then fell as more claims were added and scepticism set in.
So what does this mean for you as a writer?
- The obvious lesson is that rather than summarizing all the evidence or positive information at your disposal, you should think about which three claims are most likely to appeal to your readers – and focus on polishing those.
- Additional positives can be mentioned in passing, but remember that a long list of claimed virtues runs the risk of making your narrative less, not more, credible.
- If you really want to list all the pros, you might offset reader scepticism by also listing some carefully selected cons – thus creating an appearance of objectivity.
- And remember that the magic number three is only relevant if readers suspect an ulterior motive. Couch your writing as pure description, rather than persuasion, and the set size effect means the more positives you cite the more positive the reception from your readers.
