New research published in the journal Evolutionary Psychology suggests that a woman’s waist-to-stature ratio is a better predictor of her physical attractiveness than her waist-to-hip ratio.

Previous studies have found that women with a waist-to-hip ratio of .60 to .70 are more consistently rated as highly attractive by men. But the new study assessed the physical attractiveness of 106 college women, 673 Playboy Playmates of the Month and 490 images of imaginary women — and concluded that waist size was the key determinant of female bodily attractiveness.

PsyPost interviewed the study’s corresponding author, William D. Lassek of the University of Pittsburgh. Read his answers below:

Why were you interested in this topic?

Since the only thing that evolution cares about is success in having offspring that reproduce, the brains of men should be wired to promote their having more children. This means that the qualities that find attractive in women women should help them have more and better children. Among those qualities are the low waist-hip ratios that give women their hourglass figures, although these only seem to be attractive in relatively slender women. There have been many studies showing that lower waist-hip ratios in women are more attractive but none have used images of imaginary women, such as those found in comics, graphic novels, animated films, and video games.

What should the average person take away from your study?

We found that the waist size in relation to a woman’s height is the major factor that determines her bodily attractiveness and that this is more important than her waist-hip ratio or weight. More importantly, we found that imaginary women have impossibly small waist sizes but moderate sized hips, giving them impossibly small ratios. Jessica Rabbit, the most popular imaginary woman, has a waist size of just 10 inches and a waist-hip ratio of 0.39 compared with 0.74 in a typical young woman. This suggests that the widely held belief that the features that make women attractive indicate better health and fertility may be wrong.

Are there any major caveats? What questions still need to be addressed?

We believe that there must be some reason other than better health or fertility that attracts men to women with tiny waists. Research into women’s attractiveness should consider the role of waist size separately from waist-hip ratio.

The study, “What Makes Jessica Rabbit Sexy? Contrasting Roles of Waist and Hip Size,” was co-authored by Steven J. C. Gaulin.