Are you being watched? It can change your behaviour and choices for the better without you realising, says Jason G Goldman.

If there is one thing that the rise of social media has taught us it's how to carefully curate the information we present to the digital world. We think about all the potential eyeballs scanning our Twitter feeds, our blogs, and our LinkedIn pages. High school students are warned that college admissions officers might find them online, and hopeful job applicants scrub their Facebook pages of embarrassing photos. Google has abolished the traditional blind date. Our online activities are an exercise in reputation management.

Our species' penchant for presenting the best versions of ourselves under the prying gaze of watchful eyes isn't a technological phenomenon. How many of us haven't acted a bit selfishly when we thought we could get away with it, but behaved righteously when being observed?

In fact, we're so sensitive to being watched that even just a drawing or photograph of a pair of eyes influences our decisions. And we don't even have to be consciously aware of those eyes in the first place. Are humans alone in such behaviour?

More than 360 children unknowingly participated in a clever psychology experiment in 1976 that demonstrated this effect. It was Halloween night, and children were out knocking on doors collecting candy. Psychologists positioned themselves inside 18 different homes, and prepared themselves for the stream of costumed children seeking sweets. After opening the door and chatting with the children for a minute or two, they’d tell them to take a single piece of candy from a bowl chockfull with treats, and no more. The researchers then left the children alone with the candy bowl and, half the time, with a mirror. A second hidden experimenter covertly recorded the kids' behavior. The researchers reasoned that children might be less likely to take a sneaky handful of sweets if they could see their own reflection in the mirror.

And that's just what they found. When faced with a reflection of their own faces, even masked by a Halloween costume, the kids were more likely to behave.

Under scrutiny

Approaching the question from a different perspective, a group of researchers from the University of Newcastle in the UK found that watchful eyes could reduce the number of bicycles stolen. By using the university's crime database, they identified three spots on campus that suffered extremely high rates of bike theft, and installed signs at each location. The signs featured a pair of male eyes gazing outwards, along with the headline "Cycle Thieves: We Are Watching You”, the name "Operation Crackdown”, and the logo of a local police service. The signs caused an impressive 62% decrease in thefts in each of the three locations. Unfortunately, there was an equivalent increase in thefts elsewhere. While the intervention only displaced the thieves to other spots on campus, it was clear that the feeling of being watched was an effective deterrent.

When this sign was posted in a university campus, cycle theft dropped. (Nettle et al/Operation Crackdown)

When this sign was posted in a university campus, cycle theft dropped. (Nettle et al/Operation Crackdown)

Later that year, with the "Operation Crackdown" signs still up, the same researchers returned to the three experimental sites on campus to see whether the same watchful eyes would crack down on littering, despite the fact that the signs were explicitly written to discourage bike theft. To stack the odds against the experiment participants, the researchers used a rubber band to affix a flyer to the handlebars of each bike, giving them the opportunity to just drop the paper onto the ground. Half the time, the researchers pre-littered the area, which they suspected might have made people more likely to litter. After all, what's one more piece of paper? So they pitted the watchful eyes against the already littered ground. As expected, the eyes made the unwitting participants less likely to litter (compared with spots without the signs), and the pre-littered ground did not make it any more likely.

The extreme sensitivity that humans have to being watched, however, doesn't extend to our non-human cousins. Recently some of the same Newcastle University psychologists, together with primatologists from the Max Planck Institute for Evolutionary Anthropology, turned their eyes towards the chimpanzees of Zambia's Chimfunshi Wildlife Orphanage Trust. The chimpanzees were given the opportunity to take peanuts, a highly valued treat, from in front of a sign on which a pair of chimpanzee eyes were printed. Since chimpanzee society is strictly hierarchical, the researchers thought that the more subordinate individuals might be less likely to grab a snack, or they might opt for a lower-value carrot instead of a peanut. And the more dominant individuals might reach first for the peanuts closer to the watching chimp eyes in an effort to take all the food for themselves. Surprisingly, the chimps didn't care at all about the watchful eyes.

Other research has confirmed this: in another study, chimpanzees also failed to change their behaviour despite being watched by a fellow chimp. If chimpanzees carefully attended to their reputations like humans do, then the presence of a third party should make them more likely to share. That's a pattern seen in humans quite often; we're more likely to cooperate or to share with others when our reputations are on the line, and we can act more selfishly if we're not being watched.

It isn't that chimpanzees aren't aware of eyes more generally. Eye-tracking studies have shown that chimps and humans scan faces in similar ways, paying special attention first to the eyes, and then to the mouth. Chimps know when they’re under scrutiny; they just don't care.

Humans, on the other hand, care a great deal about being watched. We change our behaviour and choices without even realising. And that applies even when we’re under the gaze of a pair of eyes on a poster.

If you would like to comment on this, or anything else you have seen on Future, head over to our Facebook or Google+ page, or message us on Twitter.