One definition of Abnormality is deviation of Social Norms. Social norms are accepted ways of behaving within a society. They are the unwritten rules that members of a society regard as being normal and acceptable, and any deviation from them can be regarded as abnormal behaviour. Examples include ways of dressing, such as women wearing feminine clothing and men wearing masculine clothing, not appearing naked in public, saying 'please' and 'thank you', opening doors for women and elderly people etc. Social norms may, however, vary between cultures - clothing is an example of this as some African tribes wear very little clothing whereas Western cultures keep certain areas of the body covered at all times. The problem with defining abnormality as deviation from social norms is that probably the majority of behaviour that deviates from social norms is unlikely to represent mental illness. Eccentric behaviours, for example the case of John Slater (Weekes & James, 1995) who lived in a cave that was often flooded by seawater because the open space helped him think more clearly, are not necessarily abnormal to the extent that health is harmed.
A limitation of deviation from social norms is that different cultures behave in different ways in the same situation. Western cultures may experience a different social display of grief for a bereavement when compared with Indian or African cultures. Another would be that eccentric behaviours, such as running naked across a rugby pitch during a rugby match, are not necessarily psychologically abnormal.
Another definition of Abnormality is Failure to Function Adequately. Rosenhan & Seligman (1989) suggested that psychological abnormality should be defined as a range of characteristics that suggest a person is failing to function adequately in their daily life. Essentially this means that they may not be able to adapt to life healthily, may be experiencing personal