Every year, People Magazine publishes a list of the world's most beautiful people. Whilst it's not the most scientific list ever created (I, for instance, have never even made the top 10), it does provide some interesting insight into how standards of beauty change over time.

Scientists at the University of Boston have studied the list over the years and discovered that the average age of the World's Most Beautiful has gone up considerably over the last three decades. The findings are published in JAMA Dermatology. 

The average age of people judged to be the most beautiful in the world has increased from 33.2 to 38.9, whilst there have also been changes in how many non-white people made the list.

The age of celebrities on the list has seen an increase, with actors such as Sharon Stone and Michelle Pfieffer, both 59, bringing the average age up compared to when they first made the list 27 years ago. 

Researchers compared the 50 people on the list from 1990, when People first started doing it, to the 135 celebrities on the list in 2017. They compared the demographics of both lists – age, gender, race – along with things such as hair and eye color, as well as skin tone. They found that – in 1990 – 88 percent of the celebrities on the list had lighter skin tones, whereas in 2017 this has gone down to 70 percent.

The proportion of non-white celebrities went up from 24 percent in 1990 to 40 percent in 2017, though only four women of color have topped the list since its creation – Hally Berry, Beyoncé, Jennifer Lopez, and Lupita Nyong'o. Mixed-race celebrities made up only 2 percent of the list in 1990, rising to 10 percent in 2017.

The list, which features both genders, also saw a big decrease in the proportion of men deemed pretty enough to be featured. In 1990 men made up 48 percent of the list. This year only 22 percent was male.

The list is put together through a mix of reader nominations, the opinions of People's staff, and selections from modeling agents and photographers. The researchers suggested that it influences as well as reflects norms of beauty.

"The mass media platform has for years introduced certain criteria for what constitutes beauty," the researchers wrote. “We found that these beauty standards are evolving as people learn how to integrate the effects of media with exposure to new cultures and different norms."

"The perception of attractiveness is also influenced by more than these static physical characteristics. Ideals of beauty are often particular to the beholder and determined by the norms of a society, culture, or historical period."