News - April 2, 2009


Half-empty shelves in the supermarket work like magnets, Wageningen consumer research has shown. That last bottle of wine left on the shelf must be good, mustn’t it? Otherwise it wouldn’t be the only one left.

The lonely bottle that must be good.
Experts call this the bandwagon effect. The average consumer goes for products that are in demand. Dr. Erica Herpen of Market Research and Consumer Behaviour has published an article about this in the latest issue of the Journal of Consumer Psychology.

Van Herpen bases her claim on experiments in which consumers choose under controlled conditions between wine from full shelves and wine from half-empty shelves. The results are clear: we are herd animals. Not only do we take the wine from the half-empty shelf, but we also think it is better. Objectively, this is nonsense. We just think the wine is better because so many people have already bought a bottle.

Yet Van Herpen doesn’t believe that people are misled by half-empty shelves. ‘No, why? It gives you some information to go on if you are standing in front of a shelf and you don’t know what to choose. You piggyback on the collective knowledge of others. Because among those others there are always one or two people who do know which wine is good.’ In any case, the effect doesn’t always apply. Not everyone is a follower.

Nor does Van Herpen think that supermarkets deliberately keep shelves a bit empty to boost demand. ‘No, they try to keep them as full as possible. That looks nice. And anyway, there’s a risk attached to almost empty shelves. The demand can be so big that the product sells out, and then you get disappointed customers.’

The bandwagon effect does not apply to all products, though. With cars, shoes and clothes, the opposite effect is at work. We would rather not buy clothes that have already sold well, because we don’t want to be seen at the office in the same top as a colleague. According to Van Herpen, that would undermine our ‘unique identity’. ‘Fashion stores consciously try to prevent people from getting the idea that everyone is already walking around in their clothes.’