Coffee room drinkers pay more when watched by a pair of “Big Brother” eyes (Image: Newcastle University)

We all know the scene: the departmental coffee room, with the price list for tea and coffee on the wall and the “honesty box” where you pay for your drinks – or not, because no one is watching.

In a finding that will have office managers everywhere scurrying for the photocopier, researchers have discovered that merely a picture of watching eyes nearly trebled the amount of money put in the box.

Melissa Bateson and colleagues at Newcastle University, UK, put up new price lists each week in their psychology department coffee room. Prices were unchanged, but each week there was a photocopied picture at the top of the list, measuring 15 by 3 centimetres, of either flowers or the eyes of real faces. The faces varied but the eyes always looked directly at the observer.


In weeks with eyes on the list, staff paid 2.76 times as much for their drinks as in weeks with flowers. “Frankly we were staggered by the size of the effect,” Gilbert Roberts, one of the researchers, told New Scientist.

Powerful signal

Eyes are known to be a powerful perceptual signal for humans. People behave more cooperatively when they are being “watched” by a cute image of a robot (see Pay up, you are being watched) or even abstract “eye spots” on a computer screen.

But this, says Roberts, is the first time anyone has observed the effect in a natural situation, with people using their own money.

It could have far-reaching implications. In previous experiments, people consistently appeared to behave more generously than they needed to for their own self-interest, even when told their actions were anonymous. This has led an influential school of economists to argue that altruism in humans is innate, rather than being based on cynical self-interest.

But if just a photocopied pair of eyes can treble honesty, the Newcastle team suspects that these previous experiments may somehow have been spoiled by subliminal cues that made people feel they were being watched.

In other words, self-interest may play a large part after all, with people feeling the need to be seen as honest. “Those results might need to be re-examined,” says Roberts.

Meanwhile, the Newcastle team wants to repeat the work with more people, in different situations, perhaps posting pictures of eyes where tickets are sold for public transport. They would also like to discover what kind of eyes work best.

Journal reference: Biology Letters (DOI: 10.1098/rsbl.2006.0509)