On the morning of 27 February 1967 Robert Zajonc's attention was caught by a puzzling story in the Corvallis Gazette-Times. The article reported that:
A mysterious student has been attending a class at Oregon State University for the past two months enveloped in a big black bag. Only his bare feet show. Each Monday, Wednesday, and Friday at 11:00 A.M. the Black Bag sits on a small table near the back of the classroom. The class is Speech 113 - basic persuasion...Charles Goetzinger, professor of the class, knows the identity of the person inside. None of the 20 students in the class do. Goetzinger said the students' attitude changed from hostility toward the Black Bag to curiosity and finally to friendship.
Zajonc wasn't content to merely chuckle at this oddity. He wondered whether the students' gradual acceptance of the strange sight, was representative of a broader trait: that familiarity breeds fondness. And as a professor of psychology at the University of Michigan, he was perfectly placed to find out.
Putting the theory to the test
He recruited 72 students and showed them a variety of Chinese symbols - some symbols were shown once; others were displayed up to 25 times. Finally, Zajonc asked the participants to rate the symbols. The result? In eleven out of twelve cases participants preferred the symbols they'd seen the most.
But were the results a statistical fluke? Zajonc repeated the test to find out - sometimes replacing the Chinese symbols with nonsense words, sometimes with yearbook photos. Each time the findings were identical: the more an image was viewed, the more it was liked.
The bias became known as the mere exposure effect. So named because preference was driven by familiarity alone - it didn't require information or positive emotional associations as might be expected.
How should advertisers react?
The findings suggest that high frequency ads will have a positive effect, regardless of their content, as long as they fulfil basic criteria. As Jeremy Bullmore wrote in a recent essay:
Reluctant though the advertising trade may be to admit it...just about any advertising, as long as it follows a couple of primitive rules, will have some value. This, then, is the first and most basic truth about advertising: If the medium you've chosen reaches the people you want to reach, and if your medium clearly carries the name of your brand, your money will not have been wasted.
Bullmore stresses that brands shouldn't be content with mediocre advertising. On the contrary, if the mere exposure effect protects brands from complete failure then they're liberated to experiment. There's minimal downside. In Bullmore's wise words:
the penalties for getting it wrong will be barely measurable. The rewards for getting it right can be heady.
The other application, alongside the drive for experimentation, is that we should spend more time budget setting. Presently, budgeting is only a small part of the planning process. However, the mere exposure effect suggests that having enough budget to ensure constant presence is crucial.
Perhaps the best advice an agency can provide is to encourage a brand to spend - and to spend heavily.
This may not flatter our egos; after all complex strategies are a great way of intellectual grand-standing. But it's the best advice that we can give.