An extract on #bearded
Throughout the course of history, societal attitudes toward male beards have varied widely depending on factors such as prevailing cultural-religious traditions and the current era's fashion trends. Some religions (such as Sikhism) have considered a full beard to be absolutely essential for all males able to grow one, and mandate it as part of their official dogma. Other cultures, even while not officially mandating it, view a beard as central to a man's virility, exemplifying such virtues as wisdom, strength, sexual prowess and high social status. However, in cultures where facial hair is uncommon (or currently out of fashion), beards may be associated with poor hygiene or a "savage", uncivilized, or even dangerous demeanor.
The beard develops during puberty. Beard growth is linked to stimulation of hair follicles in the area by dihydrotestosterone (DHT), which continues to affect beard growth after puberty. Various hormones stimulate hair follicles from different areas. DHT, for example, may also promote short-term pogonotrophy (i.e., the growing of facial hair). For example, a scientist who chose to remain anonymous spent several weeks on a remote island in comparative isolation. He noticed that his beard growth diminished, but the day before he was due to leave the island it increased again, reaching unusually high rates of growth during the first day or two on the mainland. He studied the effect and concluded that the stimulus for increased beard growth was related to the resumption of sexual activity. However, at that time professional pogonologists, such as R.M. Hardisty, dismissed a connection. Despite DHT's relationship with terminal body and facial hair growth, the dominant hormone in facial hair development is likely the male sex hormone testosterone, with DHT more closely associated with beard growth speed rather than density (or "coverage"); moreover, neither hormone acts alone, depending instead on the quantity of androgen receptors on the face. Subjects with a greater preponderance of receptors will develop more terminal adult facial hairs.
Beard growth rate is also genetic.
Biologists characterize beards as a secondary sexual characteristic because they are unique to one sex, yet do not play a direct role in reproduction. Charles Darwin first suggested possible evolutionary explanation of beards in his work The Descent of Man, which hypothesized that the process of sexual selection may have led to beards. Modern biologists have reaffirmed the role of sexual selection in the evolution of beards, concluding that there is evidence that a majority of females find men with beards more attractive than men without beards.
Evolutionary psychology explanations for the existence of beards include signalling sexual maturity and signalling dominance by increasing perceived size of jaws, and clean-shaved faces are rated less dominant than bearded. Some scholars assert that it is not yet established whether the sexual selection leading to beards is rooted in attractiveness (inter-sexual selection) or dominance (intra-sexual selection). A beard can be explained as an indicator of a male's overall condition. The rate of facial hairiness appears to influence male attractiveness. The presence of a beard makes the male vulnerable in fights, which is costly, so biologists have speculated that there must be other evolutionary benefits that outweigh that drawback. Excess testosterone evidenced by the beard may indicate mild immunosuppression, which may support spermatogenesis.