gay men who identify as "only bottoms" tend to prefer taller men. In romances in Middle English literature, all of the "ideal" male heroes are tall, and the vast majority of the "valiant" male heroes are tall too. Most men tend to be taller than their female partners. It has been found that, in Western societies, most men prefer women shorter than themselves. Having said this, height is a more important factor for a woman when choosing a man than it is for a man choosing a woman. Western men tend to view women taller than themselves as less attractive, and people view heterosexual couples where the woman is taller to be less ideal. Women who are 0.7 to 1.7 standard deviations below the mean female height have been reported to be the most reproductively successful, since fewer tall women get married compared to shorter women. However, in other ethnic groups, such as the Hadza people from Tanzania, a study has found that height is irrelevant in choosing a mate. Another study found the same preference in rural Gambia. In Middle English literature, "tallness" is a characteristic of ideally beautiful women. The British Fashion Model Agents Association (BFMA) says that female models should be at least tall. Body language Standing postures Standing in a contrapposto posture (with bodyweight predominantly supported by one leg which is either straight, or very slightly bent, and with the other leg slightly bent) has been found to be more attractive looking than standing in a more plain, upright posture. This was found to be the case for both men and women. This posture may lower a person's observable waist-hip ratio and make their hips look wider and their waists thinner. For women especially, this can accentuate the curvature of their figure on one side of their body and make them seem more attractive. Such poses have been used in historical sculpture to emphasize an ideal of physical beauty. Movement patterns The way an individual moves can indicate health and even age and influence attractiveness. A study reflecting the views of 700 individuals and that involved animated representations of people walking, found that the physical attractiveness of women increased by about 50 percent when they walked with a hip sway. Similarly, the perceived attractiveness of males doubled when they moved with a swagger in their shoulders. Interpersonal attraction In the social psychology perspective, interpersonal attraction is