Psychologists at Turkey’s Bilkent University provided 300 men with pictures of women’s silhouettes with different degrees of spinal curvature. The men were partial to a 45.5 degree of spine curvature because that made their butt look larger. Men considered the women with big butts due to spine curvature as the most attractive.

The study explains men’s partiality to Kim Kardashian and Jennifer Lopez’s behinds.

They are believed to have the right curves.