Despite the many different cultures, the paintings all showed a strong similarity to landscape calendar art. The authors argued that this similarity was in fact due to the influence of the Western calendar industry. Another explanation is that these features are those evolutionary psychology predicts should be popular for evolutionary reasons. Physical attractiveness Various evolutionary concerns have been argued to influence what is perceived to be physically attractive. Such evolutionary based preferences are not necessarily static but may vary depending on environmental cues. Thus, availability of food influences which female body size is attractive which may have evolutionary reasons. Societies with food scarcities prefer larger female body size than societies having plenty of food. In Western society males who are hungry prefer a larger female body size than they do when not hungry. Mate selection An important adaptive function of courtship seems to be the selection of a mating partner with characteristics that would likely optimize reproductive success (selection for fitness). Such features include particular male or female characteristics that have aesthetic appeal to the opposite sex. Sexual selection tends to give rise to competition between individuals of the same gender. Darwin regarded such competition as having molded numerous aspects of animal behavior. Darwin particularly emphasized the striking evolution of aesthetic display in male birds. He also considered that a similar process had occurred in humans leading, for example, to the evolution of female beauty and sweeter voice and, in males, to the beard. Evolutionary musicology Evolutionary musicology is a subfield of biomusicology that grounds the psychological mechanisms of music perception and production in evolutionary theory. It covers vocal communication in non-human animal species, theories of the evolution of human music, and cross-cultural human universals in musical ability and processing. It also includes evolutionary explanations for what is considered aesthetically pleasing or not. Darwinian literary studies Darwinian Literary Studies (aka Literary Darwinism) is a branch of literary criticism that studies literature, including aesthetical aspects, in the context of evolution. Evolution of emotion Aesthetics are tied to emotions. There are several explanations regarding the evolution of emotion. One example is the emotion of disgust which has been argued to have evolved in order to avoid several harmful actions such as infectious diseases due to contact with spoiled foods, feces, and decaying bodies. Sexy son hypothesis, handicap principle, and arts The sexy son hypothesis suggests that a female optimal choice among potential