The psychology term for a person who doesn't care about what others think is "nonconformist" or "nonconformity." Nonconformity refers to the behavior or attitude of individuals who do not conform to the prevailing norms, values, or expectations of a particular social group or society. These individuals may resist social pressures to conform and often express independence in their thoughts, beliefs, actions, or appearance.
It's important to note that nonconformity can manifest in various degrees and contexts. Some people might be nonconformist in certain aspects of their lives while conforming in others. Additionally, the reasons for nonconformity can vary, ranging from a desire for personal autonomy and authenticity to rebellion against perceived unjust norms or a pursuit of creative self-expression.
It's also worth mentioning that nonconformity is a complex psychological concept, and different psychological theories and perspectives might interpret and explain it in various ways. Some psychological theories emphasize the role of personality traits, such as openness to experience or conscientiousness, in influencing nonconformist behavior. Others might focus on the influence of social factors or the interplay between individual and cultural influences.