Avatars and robots are increasingly appealing people these days, courtesy video games and blockbuster movies.

Now, Karl MacDorman of Indiana University in Indianapolis, Indiana, wanted to find out how people treated avatars when faced with an ethical dilemma, reports New Scientist.

To reach the conclusion, the expert presented 682 volunteers with a dilemma. Playing a doctor's role, the volunteers were faced with a female avatar, Kelly Gordon, pleading with them not to tell her husband at his next check-up that she had contracted genital herpes.

The dilemma is intended to make medical students consider issues like doctor-patient confidentiality, not to produce a right or wrong answer, says MacDorman.

Gordon was presented to the volunteers in one of four different ways, either as an actress superimposed on a computer generated (CG) background or a CG female on the same background (pictured) - and then either edited to move smoothly or in a jerky, unnatural way.

On the whole, females responded more sympathetically to Gordon, with 52 per cent acceding to her request compared with 45 per cent of men. But whereas women's attitudes were consistent however Gordon was presented, the male volunteers' attitudes swung sharply. The two human versions got a far more sympathetic hearing than their avatar counterparts.

"Clearly, presentational factors influence people's decisions, including decisions of moral and ethical consequence," says MacDorman.

"The different response from volunteers could suggest men showed more empathy towards characters that they see as a potential mate," he says.