DEFINITIONS OF ABNORMALITY
● Need to be able to define them in order to understand, predict, research, and treat
● Statistical infrequency + deviation from social norms + failure to function adequately + deviation from
ideal mental health
● No definition that will cover everything
○ Looking for a systematic + objective + unbiased + robust + exhaustive + measure way to
identify and define abnormality
Statistical infrequency
● Most scientific
● Objective, relatively unbiased, systematic, measurable
● Distribution curves + standard deviation
● Mathematically window = normal
● Allows you to identify behaviours that are statistically infrequent = abnormal
● Not up to opinion
● Doesn’t take individual differences into account (could be on the statistical line)
● Doesn’t account for behaviour that is infrequent/abnormal but desirable/positive
Evaluation
● Some abnormal behaviours are desirable
○ E.g. very few people have an IQ over 150 but this abnormality is desirable
○ There are some 'normal' behaviours that are undesirable
■ E.g. depression
○ Using statistical infrequency to define abnormality means that we are unable to distinguish
between desirable and undesirable behaviours
● The cut-off point is subjective
○ If abnormality is defined in terms of statistical infrequency - need to decide where to separate
the normal from the abnormal
■ E.g. symptom of depression is difficulty sleeping - some might think abnormal sleep is
less than 6 hours a night but others might think the cut-off should be 5
● Statistical infrequency is sometimes appropriate
○ Example: intellectual disability is defined in terms of the normal distribution using the concept if
standard deviation to establish a cut-off point for abnormality. Any individual whose IQ is more
than 2 standard deviations below the mean is judged as having a mental disorder - however,
such a diagnosis is only made in conjunction with failure to function adequately
● Cultural relativism
○ Behaviours that are statistically infrequent in 1 culture may be statistically more frequent in
another
○ The problem is in practice is that there are no universal standards or rules for labelling
behaviour as abnormal
Deviation from social norms
● Extremely subjective
● Allows for individual differences
● Acknowledges that different societies have different norms
● Unbiased to certain extent
● Robust + exhausted
● Not very measurable/objective/systematic
● Who decides the social norms
Evaluation
● Susceptible to abuse
○ What is socially acceptable now may not have been socially acceptable 50 years ago
■ E.g. homosexuality is acceptable in most countries in the world but in the past it was
included under sexual and gender identity disorders in the DSM + 50 years ago in
● Need to be able to define them in order to understand, predict, research, and treat
● Statistical infrequency + deviation from social norms + failure to function adequately + deviation from
ideal mental health
● No definition that will cover everything
○ Looking for a systematic + objective + unbiased + robust + exhaustive + measure way to
identify and define abnormality
Statistical infrequency
● Most scientific
● Objective, relatively unbiased, systematic, measurable
● Distribution curves + standard deviation
● Mathematically window = normal
● Allows you to identify behaviours that are statistically infrequent = abnormal
● Not up to opinion
● Doesn’t take individual differences into account (could be on the statistical line)
● Doesn’t account for behaviour that is infrequent/abnormal but desirable/positive
Evaluation
● Some abnormal behaviours are desirable
○ E.g. very few people have an IQ over 150 but this abnormality is desirable
○ There are some 'normal' behaviours that are undesirable
■ E.g. depression
○ Using statistical infrequency to define abnormality means that we are unable to distinguish
between desirable and undesirable behaviours
● The cut-off point is subjective
○ If abnormality is defined in terms of statistical infrequency - need to decide where to separate
the normal from the abnormal
■ E.g. symptom of depression is difficulty sleeping - some might think abnormal sleep is
less than 6 hours a night but others might think the cut-off should be 5
● Statistical infrequency is sometimes appropriate
○ Example: intellectual disability is defined in terms of the normal distribution using the concept if
standard deviation to establish a cut-off point for abnormality. Any individual whose IQ is more
than 2 standard deviations below the mean is judged as having a mental disorder - however,
such a diagnosis is only made in conjunction with failure to function adequately
● Cultural relativism
○ Behaviours that are statistically infrequent in 1 culture may be statistically more frequent in
another
○ The problem is in practice is that there are no universal standards or rules for labelling
behaviour as abnormal
Deviation from social norms
● Extremely subjective
● Allows for individual differences
● Acknowledges that different societies have different norms
● Unbiased to certain extent
● Robust + exhausted
● Not very measurable/objective/systematic
● Who decides the social norms
Evaluation
● Susceptible to abuse
○ What is socially acceptable now may not have been socially acceptable 50 years ago
■ E.g. homosexuality is acceptable in most countries in the world but in the past it was
included under sexual and gender identity disorders in the DSM + 50 years ago in
