Healthy hair indicates health and youth (important in evolutionary biology). Hair colour and texture can be a sign of ethnic ancestry. Facial hair is a sign of puberty in men. White hair is a sign of age or genetics, which can be concealed with hair dye. Male pattern baldness is a sign of age, which can be concealed with a toupee, hats or religious/cultural adornments. Although drugs and medical procedures exist for the treatment of baldness, many balding men simply shave their heads. Hair whorls have been discovered to be associated with brain development.

Hairstyle can be an indicator of group membership. During the English Civil War, the followers of Oliver Cromwell decided to crop their hair close to their head, as an act of defiance to the curls and ringlets of the king's men. This led to the Parliamentary faction being nicknamedRoundheads. Having bobbed hair was popular among the flappers in the 1920s as a sign of rebellion against traditional roles for women. Female art students known as the "cropheads" also adopted the style, notably at the Slade School in London, England. Regional variations in hirsutismcause practices regarding hair on the arms and legs to differ. Some religious groups may follow certain rules regarding hair as part of religious observance. The rules often differ for men and women.

Many hippies, metalheads and Indian sadhus have long hair; many punks wear a hairstyle known as a Mohawk or other spiked and/or dyed hairstyles; skinheads have short-cropped or completely shaved heads; Mullet hairstyles have stereotypically been associated with rednecks; theDeathhawk, a larger, fuller, back-combed version of a Mohawk is popular with goths and deathrock fans; an undercut in which the sides and back of the head are shaved short or bald, and the top hair is allowed to grow long, is common among cybergoths and fans of Industrial and heavyelectronic music; hair that is usually short with a long side fringe — often dyed black or vibrant and contrasting colours — is associated with emofans.