People may be hard-wired to believe that others are staring at them even when they aren't, according to a new study.
Researchers led by the University of Sydney found that when in doubt, the human brain is more likely to tell its owner that they're under the gaze of another person.
"Gaze perception - the ability to tell what a person is looking at - is a social cue that people often take for granted," said Professor Colin Clifford of The Vision Centre and The University of Sydney.
"Judging if others are looking at us may come naturally, but it's actually not that simple - our brains have to do a lot of work behind the scenes," Clifford said.
To tell if they're under someone's gaze, people look at the position of the other person's eyes and the direction of their heads, Clifford said.
These visual cues are then sent to the brain where there are specific areas that compute this information.
However, the brain doesn't just passively receive information from the eyes, Clifford said.
The new study shows that when people have limited visual cues, such as in dark conditions or when the other person is wearing sunglasses, the brain takes over with what it 'knows'.
In the study, the researchers created images of faces and asked people to observe where the faces were looking.
"We made it difficult for the observers to see where the eyes were pointed so they would have to rely on their prior knowledge to judge the faces' direction of gaze," Clifford said.
"It turns out that we're hard-wired to believe that others are staring at us, especially when we're uncertain.
"So gaze perception doesn't only involve visual cues - our brains generate assumptions from our experiences and match them with what we see at a particular moment.
"There are several speculations to why humans have this bias. Direct gaze can signal dominance or a threat, and if you perceive something as a threat, you would not want to miss it. So assuming that the other person is looking at you may simply be a safer strategy.
"Also, direct gaze is often a social cue that the other person wants to communicate with us, so it's a signal for an upcoming interaction," Clifford said.
There is also evidence that babies have a preference for direct gaze, which suggests that this bias is innate, Clifford explained.
The study was published in the journal Current Biology.
