Using computer-generated avatars, psychologists say they have unlocked the dance moves that will capture a woman's heart. Apparently the speed of a man's right knee and the size and variety of movements of the neck and torso are key, they suggest.

Throughout the animal kingdom examples abound of males performing courtship dances, attracting females with displays of health and skill. Dances are sexy among humans as well, and scientists wanted to codify what moves ladies like to see in men.

Psychologists at Northumbria University in England filmed 19 male volunteers, ages 18 to 35, with a 12-camera system as the men danced to a German dance track, the kind of drum rhythm one might hear clubbing. None of them were professional dancers.

The men also wore 38 small reflectors all over their body, which the systems monitored to capture the motions of the dancers in three dimensions — the same technique filmmakers used to help create the character of Gollum in the "Lord of the Rings" movies. These movements were mapped onto featureless, white, gender-neutral humanoid characters, or avatars. [Video - Watch the avatars dance.]

This way, the 35 heterosexual women the scientists also recruited could rate 15-second clips of each dancer without being prejudiced by each guy's individual level of physical attractiveness. Each dancer was judged on a scale of one to seven, from extremely bad to extremely good.

Guys whose swagger included larger and more variable movements of the neck and torso were considered attractive by the ladies.

"This is the first study to show objectively what differentiates a good dancer from a bad one," said researcher Nick Neave, a psychologist at Northumbria University. "Men all over the world will be interested to know what moves they can throw to attract women."

Curiously, faster bending and twisting movements of the right knee also seemed to catch the eyes of women. As a potential explanation, the researchers noted that 80 percent of all people are right-footed, so most people "are putting their weight on their left leg and using that leg as an anchor while the right can do more fancy things," Neave suggested. "It is a bit of an odd finding, so we need more studies to see if this feature is replicated."

He added: "We now know which area of the body females are looking at when they are making a judgment about male dance attractiveness. If a man knows what the key moves are, he can get some training and improve his chances of attracting a female through his dance style."

In the online version of the journal Biology Letters Sept. 8, the researchers suggest these dance movements could be signs of male health, vigor or strength that men would find hard to fake. Neave said they have preliminary data to show that better dancers are also healthier and are more attractive, and they are exploring these ideas in current research studies.

"The hardest thing is to recruit males to take part," Neave told LiveScience. "They seem rather reluctant to sign up for studies that involve dancing."

Male avatars reveal the dance moves that ladies like, including moves with more twisting and bending of a guy's knee and larger head and torso movements.