The chances are, you remember this poster, part of a Cancer Research UK campaign that ran last year.

But why do you recall it? Possibly partly due to the controversy surrounding it. The campaign was slated for “fat shaming”, an accusation denied by Cancer Research.

But the impact of this campaign is also down to the smart technique employed in the creative – a phenomenon known as the generation effect. This describes a bias in which people are more likely to retain information when they need to generate an answer, compared to having the same information provided. In order to read the headline, your brain must fill in the blanks. The work involved in understanding the word OBESITY is in part what makes it stick.

Generating evidence

The generation effect is a memory bias, first reported by Norman Slamecka and Peter Graf at the University of Toronto in 1978. They devised a study to explore whether self-generated words are easier to remember than externally provided words.

A group of 24 students were shown 100 cards featuring two associated words. For half of the participants, the cards showed a stimulus word and the first letter of another. They were tasked with solving the second word, based on its given association with the first – for example, rapid-f (synonyms). The other half of participants saw both words in full and simply had to read them – for example, rapid-fast. Once they’d read all the cards, the researchers tested recall with a follow-up recognition task.

The results were highly significant – the group who had generated words were 15% more likely to remember words compared with participants who had simply read them from the cards.

Evolving the idea

The Cancer Research campaign makes you think for a moment. But can you encourage deeper thinking?

Even better if you can put the generation effect to use more meaningfully in relation to your campaign. The technique has been used to great effect by NHS Blood and Transplant and the American Red Cross in the #MissingType campaign, which removed the letters A, B, and O from logos and headlines to highlight the need for donations of these blood types.

And was also used cleverly by J&B Whisky, Christmas 1990.

A lateral application

Still, these examples use the generation effect literally. Psychological biases are most powerful when they’re used in a lateral manner.

The Economist ad below is an example of a lateral interpretation of the generation effect.

The creative hasn’t removed any letters but, by making its point obliquely, it requires a bit of mental processing, thereby ensuring memorability. The strength of this lateral approach is that you can run a whole series of ads, whereas there are only so many times you can run ads with letters removed.

The best ads are memorable because they make you work a little: you feel a bit clever for figuring them out and you want to talk about them with your friends. The skill of great creative is to balance the effort of solving the puzzle with enough stopping power to get people to pause and think.

So next time you’re devising creative, think about what you can leave out.

The team at The Behaviours Agency are combining their strong creative thinking with insights from behavioural science to develop more impactful and effective ideas for clients, and I’m pleased to be working with them as well.

Read the research: Journal of Experimental Psychology: Human Learning and Memory 1978, Vol. 4, No. 6, 592-604.