Everyone knows that men using a public restroom are more apt to wash their hands — or at least go through the motions of washing their hands — if they're not alone.
Of course, that doesn't apply to yours truly.
But I digress.
Now come scientists who report that just a picture on the wall of a pair of human eyes is enough to make people act as if an actual person were present.
Who knew that you could cut down on fecal transmission of disease with just a poster?
Not moi, fer shur.
Here are excerpts from Sander van der Linden's Scientific American article on this eye-opening development.
Thomas Jefferson wrote, "Whenever you do a thing, act as if all the world were watching." I always found this to be a particularly interesting quote, as it reminds us of the fact that we tend to be on our best behavior when we know that we are being observed. While this may seem obvious, new research points to something far less obvious: it doesn't take a fellow human being to make us feel "as if the world were watching," not even another living organism. All it takes is an image of a pair of human eyes.
A group of scientists at Newcastle University, headed by Melissa Bateson and Daniel Nettle of the Center for Behavior and Evolution, conducted a field experiment demonstrating that merely hanging up posters of staring human eyes is enough to significantly change people's behavior. Over the course of 32 days, the scientists spent many hours recording customer's "littering behavior" in their university's main cafeteria, counting the number of people that cleaned up after themselves after they had finished their meals. In their study, the researchers determined the effect of the eyes on individual behavior by controlling for several conditions (e.g. posters with a corresponding verbal text, without any text, male versus female faces, posters of something unrelated like flowers, etc). The posters were hung at eye-level and every day the location of each poster was randomly determined. The researchers found that during periods when the posters of eyes, instead of flowers, overlooked the diners, twice as many people cleaned up after themselves.
Below, the abstract of the Newcastle University study cited above, published in Evolution and Human Behavior.
Effects of eye images on everyday cooperative behavior: a field experiment
Laboratory studies have shown that images of eyes can cause people to behave more cooperatively in some economic games, and in a previous experiment, we found that eye images increased the level of contributions to an honesty box. However, the generality and robustness of the eyes effect is not known. Here, we extended our research on the effects of eye images on cooperative behavior to a novel context — littering behavior in a university cafeteria — and attempted to elucidate the mechanism by which they work, by displaying them both in conjunction with, and not associated with, verbal messages to clear one's litter. We found a halving of the odds of littering in the presence of posters featuring eyes, as compared to posters featuring flowers. This effect was independent of whether the poster exhorted litter clearing or contained an unrelated message, suggesting that the effect of eye images cannot be explained by their drawing attention to verbal instructions. There was some support for the hypothesis that eye images had a larger effect when there were few people in the café than when the café was busy. Our results confirm that the effects of subtle cues of observation on cooperative behavior can be large in certain real-world contexts.