Baldness Evolutionary hypotheses 

There is no consensus regarding the details of the evolution of male pattern baldness. The assertion that MPB is intended to convey a social message is supported by the fact that the distribution of androgen receptors in the scalp differs between men & women, & older men or women with high androgen levels often exhibit diffuse thinning of hair as opposed to male pattern baldness.

Male pattern baldness is mostly the result of a genetic event that causes dihydrotestosterone , a male hormone, to cause the hair follicles to atrophy. The hair produced is progressively smaller, until it is practically invisible . It has been speculated that this is an evolutionary event that signifies maturity & conveys greater authority on affected men.

In a study by Muscarella & Cunningham, males & females viewed 6 male models with different levels of facial hair & cranial hair . Participants rated each combination on 32 adjectives related to social perceptions. Males with facial hair & those with bald or receding hair were rated as being older than those who were clean-shaven or had a full head of hair. Beards & a full head of hair were seen as being more aggressive & less socially mature, & baldness was associated with more social maturity.

Other evolutionary hypotheses include genetic linkage to beneficial traits unrelated to hair loss & genetic drift.