Bending the truth isn’t so easy when facing a pair of eyes, even when they’re not real, a recent study shows. Researchers of the Nagoya Institute of Technology found that the presence of eyes unconsciously discourages people from lying, even when those lies would benefit the less fortunate.

Led by Ryo Oda, associate professor at the Nagoya Institute, the study involved 199 Japanese university students who were subjected to the “watching eye effect” while confronting two conflicting social values: being honest and helping someone in need. Study participants were asked to roll a die to determine how much money the experimenters would donate to the Japanese Red Cross Society’s relief fund for victims of the March 11, 2012 earthquake and tsunami. Participants rolled the die privately, which gave them the opportunity to either lie or tell the truth about the amount that would be donated to charity.

Ninety-nine of the participants completed the study in a room that contained a picture of a pair of eyes — the remaining participants were not exposed to the eyes. By comparing the values of the reported die rolls to what would occur by chance, researchers could tell approximately how many people had dishonestly reported their rolls. Upon analyzing the data, researchers found that the reported outcomes among those who were not “watched” significantly differed from what would have been expected from actual rolls. This ultimately resulted in more money being donated to charity. However, in the group that was “watched,” outcomes did not significantly deviate from what the chances predicted, and thus resulted in less money being donated to charity.

Researchers concluded from these findings that people’s desire to avoid breaking societal norms — by lying — is stronger than their desire to demonstrate generosity. Oda and his team also determined that the risks that come with being seen as dishonest may be greater than those that come with being perceived as greedy. Therefore, when these two societal norms conflict with the watching-eye effect, it makes people more likely to prioritize telling the truth over giving to others.

Psychologists theorize that this happens because humans have a basic motivation to follow rules and social norms when they think they’re being watched. The presence of eyes is thought to activate this instinct on a non-conscious level, even when it’s obvious that the eyes do not belong to a real person. Furthermore, Oda’s findings suggest it may one day be possible to influence honesty by simply exposing people to a pair of watching eyes.

Source: Oda R, Kato Y, Hiraishi K. The Watching Effect On Prosocial Lying. Evolutionary Psychology. 2015.