FRIDAY, July 2 (HealthDay News) -- The speed at which you can judge whether a member of the opposite sex is checking you out seems to depend on how masculine or feminine you look, according to a new study.

The research involved volunteers who looked at photos of faces altered to exhibit exaggerated or reduced male or female features. As the faces flashed on a computer screen, the participants had to quickly hit a key to indicate whether the face was looking at them or away from them.

Both women and men were able to hit the key more quickly when the face had exaggerated masculine or feminine traits.

"Women were quickest to classify gaze direction when they were looking at hunky, masculine-looking guys. Guys were quicker when they were looking at pretty, feminine women," Benedict C. Jones, of the University of Aberdeen in Scotland, said in an Association for Psychological Science new release.

The study is published in the June issue of the journal Psychological Science.

The ability to perceive things about attractive people may have been a useful evolutionary trait. Some previous research suggests that 'feminine' women and 'masculine' men make the healthiest mates.

"There's likely quite a big advantage to detecting when a particularly good potential mate's looking at you," Jones said. "If I'm in a bar and there's a pretty woman looking at me -- if I wasn't married -- I would want to catch her eye before someone else did."

More information

See the Nemours Foundation for more on sexual attraction.