It has emerged that avatars that can mimic our real-world eye movements can make it easier to spot if someone is telling the truth online.
Most virtual worlds, such as Second Life, are full of avatars with static or pre-programmed gazes.
One way to make interactions feel more realistic is to reproduce a person's eye movement on their avatar, said William Steptoe of University College London and colleagues.
Now they have found that real-world eye movement could make it easier to spot whether an avatar is telling the truth.
The researchers asked 11 volunteers personal questions, such as to name their favourite book, and told them to lie in some of their answers.
During the interviews, the volunteers wore eye-tracking glasses that recorded their blink rate, direction and length of gaze, and pupil dilation.
Then, a second group of 27 people watched a selection of clips of avatars as they delivered the first group's answers.
Some avatars had eye movements that mirrored those of the original volunteers, while others had no eye movement at all.
The volunteers were asked whether they believed the avatars were being truthful or lying.
On average, the participants were able to identify 88 per cent of truths correctly when the avatars had eye movement, but only 70 per cent without.
Spotting lies was harder, but eye movement provided 48 per cent accuracy compared with 39 per cent without.
It is unclear exactly how the eye movements help.
However, the eye-tracking glasses did show that people tended to hold the gaze of the interviewer for longer when telling the truth than when lying.
"Perhaps they were overcompensating," New Scientist quoted Steptoe as saying.
What's more, their pupils dilated more when lying - something previous studies have linked with the greater cognitive load required for deception.
"This is one of a small handful of cues that you can't control," said Steptoe.
Enhancing expressive features such as eye movement could eventually make avatar-mediated communication feel more trustworthy than online video, because only relevant visual cues need to be displayed, said Steptoe.
The technology could help in business meetings held in virtual environments, or to enhance communication between people with social phobias, where face-to-face interaction can seem daunting, he added.
The results of the study will be presented at the 2010 Conference on Human Factors in Computing Systems in Atlanta, Georgia.