WITH AGE, WOMEN APPEAR MORE AGGRESSIVE

Throughout history, older women have often been labelled as hags or crones, as the irreproachable bloom of youth gives way to a timeworn truculence in their countenance.

Now, scientists have found that the faces of women do indeed appear broader and more aggressive than men's after the age of 48, but the reason is more intriguing than simple biology.

Researchers in Australia have suggested that men with the most aggressive facial features may end up in jail, or die in their younger years, taking them out of society and skewing the ratio of more unappealing faces towards women in later life.

Scientists believe that humans are programmed to see broader faces as more aggressive because it is a marker of high testosterone exposure in the womb.

Experts have suggested that the facial clue may have evolved to prove power and status when other masculine signs, such as a big chin and jaw, would have been obscured by facial hair.

In a new study, researchers at the University of New South Wales, asked volunteers to look at 17,000 passport photographs and rate how aggressive they found each individual.

People in the photos were judged to be more antagonistic if they had a broad, square face, known as a high face-width-height ratio (FWHR), which marks the distance between the cheekbones divided by the distance between the mid-brow and the upper lip.

In contrast, those with oval shaped faces — a low FWHR — were deemed to be more placid and meek.

Men were most likely to be perceived as aggressive between the ages of 27 and 33, and women between 34 and 61, the study showed.

Throughout younger ages, men were consistently deemed to look more aggressive but the pattern shifted before age 50, with a greater proportion of females recording higher FWHRs than males, and so more likely to be perceived as aggressive.

The team said the switch was difficult to explain, and could be due to sex differences in where weight accumulates or decreases with age.

However, writing in the journal Royal Society Open Science, they added: “Other possibilities are that increasingly fewer males with (more aggressive faces) apply for passports later in life — perhaps because many men with the largest face-widthheight-ratio may be removed from society via incarceration, or early mortality relative to women.

“Other possibilities are that the reversal is connected to age-related structural changes to the faces, such as differences in the rate of face lengthening with age.”