It's hardly a secret that men (in a Western culture, at least) find women with long legs attractive. That's one reason why female models are usually wearing high heels. What is less obvious is that the reverse also appears to be true: Even after controlling for height, women find men with slightly longer legs than average to be more attractive.
The researchers, who are psychologists at the University of Cambridge, recruited online 74 heterosexual female participants aged 20 to 69. Each woman was shown 28 images, one at a time, and was asked to rate attractiveness on a scale from 1 (not attractive) to 7 (very attractive). As shown in the left-hand figure below, all male images were the same height. The only difference in each set of figures was the leg-to-body ratio.
The center image in each set, marked "0", represents the average leg-to-body ratio. The numbers on each side represent the number of standard deviations away from the average each image represents. For instance, the image marked "-1" means that the male has a leg-to-body ratio that is one standard deviation below average.
When the researchers crunched the numbers and added a best-fit curve, they found that women preferred men with slightly longer legs than average. (See right-hand figure.) Specifically, the most attractive male has a leg-to-body ratio that is 0.5 standard deviations above average. Men with leg-to-body ratios that were too high or too low were rated as less attractive, with short-legged men being seen as the least attractive. These results were consistent across skin colors.
The data for silhouettes (bottom row) were different. Here, women preferred men with very slightly lower leg-to-body ratios than average. However, compared to the 3D-rendered images, silhouettes are not very realistic, which may explain this inconsistent result.
The authors note that a similar study conducted in Japan showed that women preferred men with average leg-to-body ratios, which suggests that the preference for slightly longer legs may be cultural. That's one big reason why evolutionary psychology studies must always be interpreted with caution.
This research might also offer a new dating strategy for men: Throw on a pair of high heels to really catch the ladies' eyes.
Source: Thomas M. M. Versluys, William J. Skylark. "The effect of leg-to-body ratio on male attractiveness depends on the ecological validity of the figures." R. Soc. Open Sci. 4: 170399. Published: Sept 2017. doi: 10.1098/rsos.170399