Is there a science to having a good â€˜gaydarâ€™?

Australia's swimming great Ian Thorpe has attracted widespread community support after revealing he is gay.

Life in the spotlight ... Ian Thorpe in 2002. Source: News Limited

IN his coming out interview with Sir Michael Parkinson, Australian swimming champion Ian Thorpe revealed that his mother Margaret was "shocked" when he told her he was gay.

Similar sentiments were to come from Thorpe's father Ken, who told Channel Seven news on Monday night that he "had no inclination that Ian was that way inclined".

But it's doubtful many other Australians shared Mr and Mrs Thorpe's surprise.

Somehow, when it came to Thorpey, we always suspected he was gay - which perhaps explains why he was forever being badgered by the question.

But why did we think he was gay? There were no boyfriends on the scene; no incriminating photographs or kiss-and-tell confessionals from former lovers. There was never a sliver of real evidence.

OK, so there was the pearl jewellery. (Thorpe designed and spruiked a range of pearl jewellery for men and women in the years after the Sydney 2000 Olympics.) And he made some fashion choices that we might call "daring" or even "courageous".

Fashion fan ... Thorpe in Paris in 2003. Picture: Alex Zotos Source: Supplied

Pearl of an idea ... Thorpe spruiking jewellery in 2002. Source: News Limited

Despite his vehement assertions that he was heterosexual over the years, Thorpey did make some candid remarks about himself from time to time.

"You know, I'm a little bit different to what most people would consider being the Australian male," Thorpe told the ABC's Monica Attard in a 2002 interview.

The then 19-year-old suggested his lack of a "macho Australian accent" and his interest in fashion marked him out as being a bit different from the stereotypical young Australian male.

But were those things really all it took to get gaydars pinging?

According to researchers at the University of Toronto, for most people it doesn't take much to set our gaydars off. Their research suggests we can make a snap judgment about a person's sexuality just from a fleeting look at their face - and remarkably, those judgments seem to be accurate more often than not.

Psychologist Nicholas Rule from the university's Social Perception and Cognition Laboratory told the Toronto Star newspaper last month that "people can accurately judge someone's sexual orientation from very minimal information about them".

Can homosexuality be perceived just by looking at someone's face? Research says it can - sometimes. Source: Supplied

Openly gay Australian celebrities Ian Roberts and Magda Szubanski ... Source: Supplied

Rule judged that those perceptions were accurate an average of 65 percent of the time - although interestingly, self-described conservatives were more accurate when it came to ascertaining somebody's homosexuality than self-declared liberals.

"Conservatives are more accurate than liberals in making these judgments when they study a face, because conservatives are more likely to use stereotypes," Rule claimed. "Of course, stereotypes are often wrong, but they do have what we call kernels of truth. Liberals tend to not want to use stereotypes in making judgments, and it impairs their accuracy."

The Toronto research has been replicated by others who have looked into the area of first impressions.

Researchers Vivian Zayas from Cornell University and Joshua Tabak from the University of Washington showed black and white, "standardised" photos of same-sex and opposite-sex-attracted people to a group of subjects for 50 milliseconds at a time - and found that the subjects correctly assessed the sexuality of the people in the photos 60 percent of the time.

Writing in the research journal PLoS One, the researchers revealed that participants in their study "read sexual orientation more accurately from women's faces than from men's faces" and posed the question: if we can ascertain homosexuality with reasonable accuracy, just from looking at someone's face, does that make gay people vulnerable to overt and covert forms of discrimination?

The research suggests two things - the first being that a lot of people have a reasonable facility for perceiving if a person is gay or straight, just from looking at them. But conversely, the research also indicates that our gaydars are not very highly developed, either. What about the straights who are wrongly perceived as gay? Or the gay people who just don't look it?

Secrets exposed ... David Campbell in 2008 when he was NSW Police Minister. Picture: Alan Place Source: News Limited

The case of the former NSW minister David Campbell is worth mentioning here.

Mr Campbell's career as a Labor minister came to a spectacular and sudden end in May 2010, when he was filmed exiting a gay sex-on-premises venue in Sydney by a TV news crew.

The revelation of his sexual activity was a shock to his government colleagues, his wife, and his two adult sons.

Kristina Keneally, who was NSW Premier at the time, said Campbell's sexuality "was a secret that he has lived with ... for over two decades".

Why is it that Thorpe was plagued by the gay question throughout his career, while for Campbell the question never arose?

Ultimately, that's a mystery we may never solve - but the research from Rule, Taback and Zayas suggests when it comes to the science of human perceptions, there is much we still have to learn.

How good is your gaydar? Can you tell if somebody is straight or gay, just by looking at them? Comment below.