How is normal and abnormal behavior defined? What factors influence the definition? Why?

          The term "norm" refers to an authoritative standard; therefore, normal behavior correspondingly means it is behavior that abides by such standards (Allport, 1958). Hence, the term "abnormal" refers to a contradiction of an authoritative standard; therefore, abnormal behavior correspondingly means it is behavior that does not abide by such authoritative standards. Basically, normal behavior is viewed as culturally and socially normal and abnormal behavior is viewed as culturally and socially abnormal. One factor that determines whether behavior is normal or abnormal is what is considered a cultural or social norm. By taking into account what is a cultural or social norm one can determine if behavior deviates from such norms. Another factor one must consider is if behavior causes distress. If behavior does cause distress then such behavior is viewed as abnormal. Therefore, one should  determine if behavior is normal or abnormal by determining whether such behavior is socially acceptable and if it cause distress or not.  

Reference

Allport, G. W. (1958). PERSONALITY: NORMAL AND ABNORMAL. Sociological Review, 6(2), 167-180. doi:10.1111/1467-954X.ep13736717