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Definition of social norms
The rules of behaviour that are considered acceptable/normal in a group of society
Definition of deviation from social norms
Behaviours or attitudes that break the implicit or explicit rules and standards that exist within a society. For example not laughing at a funeral is an implicit social whereas causing disorder in public it's both a deviation from social norms and against the law (explicit).
(+) easy to use
A strength of the deviation from social norms definition of abnormality is that it is easy to use.
This is because it is relatively easy for a doctor/psychologist to identify when behavior breaks and unwritten or written rule.
This is a strength because this definition enables people who have a mental abnormality to be identified. Once they are identified the can recieve the appropriate treatment to make them better, faster.
Therefore, this easy to use definition can help to improve people's life quickly.
(-) Norms change
A limitation of defining abnormality as deviating from social norms is that norms are culturally and historically specific
For example until the 1970s homosexuality was listed as a mental disorder in the USA and in the UK in the last century, unmarried mothers were considered ‘morally insane’ and could be put in a mental asylums for long periods of time. However neither could be considered psychologically abnormal now.
This is a limitation because if clinicians are using culturally or historically biased norms to diagnose abnormality, they might inaccurately label someone as abnormal.
Therefore, it is very difficult to make a reliable diagnosis of abnormality using this definition as clinicians from different generations and different cultures could make different diagnoses.
(-)How do we class criminal behaviour
A limitation of defining abnormality as deviating from social norms is that criminal behavior is classes deviating from social norms but it's not a form of abnormality.
Violation of legal term of legal norms is usually regarded as criminal rather than resulting from some form of mental disorder. However, those who commit some crimes such as rape, cannibalism and mass murder are often regarded as mentally ill (typically as psychopaths).
This is a limitation because it can be difficult to be sure whether a criminal deviant is mentally ill simply because he or she chooses to ignore social norms and morality or whether they are using it as an excuse for their deviant behavior.
Therefore when it comes to criminality it can be difficult as this definition might be seen as ‘excusing’ certain behaviors.
(-) Eccentricity is not a form of abnormality
A limitation of defining abnormality as deviating from social norms is that it is too simplistic because not all behaviors that is a deviation from social norms can be judged to be psychologically abnormal.
Behaviour needs to be understood in its context/place. Some behavior such as a man wearing a suit jacket with a skirt could be regarded as abnormal or eccentric, whereas others such as walking down the street talking out loud to an invisible person would be recorded as evidence of a mental disorder.
This is limitation because only particular types of deviation from social norms would be regarded as psychologically abnormal therefore it is too simplistic to say all forms of abnormality can be defined as deviating social norms.
Therefore this is not a useful way of defining abnormality as people who are not mentally unwell might fall under this definition.