- Defining a behaviour/person as abnormal implies something undesirable and requiring change.
- Psychologists need methods for distinguishing 'normal' from 'abnormal'.
Statistical Definition of Abnormality
- A person's trait, thinking or behaviour is classified as abnormal if it is rare or statistically unusual.
- Necessary to be clear about how rare a trait or behaviour needs to be before we class it as abnormal.
- Any human characteristic is spread in a normal way across the general population.
- When plotted on a graph, it will form a normal distribution curve.
- The majority of people will fall in the middle of the graph with the minority being at either extreme end of the graph.
- The same is true of normal and abnormal behaviour.
- If someone's behaviour falls in the top or bottom 2.5% then it is considered to be abnormal.
Statistical Definition Continued...
- EXAMPLE - Average IQ in the population is 100.
- The further from 100 you look, the fewer people you find.
- If IQ falls in the bottom or top 2.5% then it is to be considered abnormal.
- EXAMPLE - 65% of the population have an IQ between 85 and 115
- So if the majority (95%) of the population have an IQ of between 70 and 130, those that fall out of this are considered abnormal.
Evaluating Statistical Definition
STRENGTH - It is an objective definition, therefore one that all clinicians can use to ensure consistency in diagnosis.
WEAKNESS - Does not give a clear-cut definition and takes away the subjectivity of clinicians diagnosis.
WEAKNESS - Doesn't take account of cultural variations.
WEAKNESS - If a person's score is only one or two above what is classed as abnormal, they may not get the help that they need.
WEAKNESS - Some behaviours that people show everyday such as anxiety may be considered normal but abnormal in a clinical sense.
Deviation From Social Norms
- Another definition of abnormality.
- Every society has accepted standards of behaviour, these are sometimes written as part of the law.
- Others are implicit: they are generally accepted but not legally binding.
- Social norms allow for the regulation of normal behaviour.
- One approach to defining abnomality is to consider deviations from social norms as an indicator of abnormal behaviour.
- A person's thinking or behaviour is classed as abnormal if it violates the rules about what is expected or acceptable behaviour in a particular social group.
Deviation From Social Norms Continued...
- Their behaviour may be incomprehensible to others or make others feel threatened or uncomfortable.
- To define people's mental health in terms of deviation from social norms suggests that those who behave in a socially deviant or incomprehensible way should be regarded as abnormal because they break with conventions and so not do what is normally expected.
- Some roles in society also come with what is considered to be normal behaviour, such as doctors are expected to be caring towards their patients.
Evaluation Of Deviation From Social Norms
WEAKNESS - Can lead to an abuse of a person's rights based on what society sees as normal.
WEAKNESS - It is culturally biased. What is unacceptable in one culture may be seen as acceptable in another culture.
STRENGTH - At times, breaking with the dominant culture is something to be applauded (freedom fighters)
STRENGTH - Allows us to consider different behaviour which may not on their own be classified as abnormal.