It was previously believed that a woman's attraction to male faces varied due to hormones.
At certain times, it appeared women subconsciously searched male faces for signs of a good provider and at other times they looked for a bad boy with good genes. The latter is known as the "Johnny Depp effect."
But new research published in the international journal, PLOS ONE , demonstrates that women's preferences may be explained by a cognitive process.
Researchers at Warwick Business School, UK; the University of Otago, New Zealand; and the University of California, San Diego, found that when people were asked to rate the attractiveness of gender-blended face morphs, they judged them as less appealing if they were first asked to classify the faces as male or female.
In other words, more feminine looking male faces were only disliked when the faces were first categorized by gender, despite an overall preference for more feminine looking features.
A second experiment asked participants to categorize gender-blended faces by ethnicity. Those participants did not judge the gender-blended faces as less appealing.
Researchers said "processing fluency" -- the ease with which we perceive, process and categorize things -- led to these results. Excess mental effort can leave us with a negative impression of something that is relatively pleasant to look at.
“The idea we tested is that the mental effort of having to assign a gender to an ambiguous face has a flow-on effect of negatively influencing how we feel about that face,” says study co-author Professor Jamin Halberstadt, of Otago’s Department of Psychology.
"The more feminine faces are generally preferred, unless the context forces the viewer to put the face into rigid gender boxes," said Piotr Winkielman, of Warwick Business School and UCSD.
So, the next time you spot someone with an ambiguous looking face, instead of trying to decide if he/she is male or female, just enjoy the view.