Defining Abnormality
How would you define normal and
Map to Spec – Page 58
1. Definition of the application
b)Define and use psychological terminology
accurately and appropriately including:
i. statistical definition of abnormality
ii. social norm definition of abnormality
Map to Spec – Page 59
3. Content
a) Describe both the statistical definition of
abnormality and the ‘social norms’ definition
of abnormality.
b) Evaluate the statistical definition of
abnormality and the ‘social norms’ definition
of abnormality
Definitions – What is normal/abnormal?
1. Statistical Infrequency
2. Deviation from social Norm’s
3. Failure to Function Adequately
4. Deviation from Ideal Mental Health
Statistical Infrequency
Statistical Infrequency
By definition abnormality means differing from the norm or average.
Statistically infrequent behaviour is regarded as abnormal, whereas
frequent behaviour is normal.
Individual characteristics can be measured (e.g., mood, intelligence, etc…)
and the distribution of these characteristics within the population can be
graphed. The normal distribution curve shows the majority of people as
being in the middle. These people are defined as ‘normal’. Relatively few
people fall at either end. However, if they are then they are defined as
For example, most “normal” people eat an
average of between 1500 to 3000 calories a day.
However, anorexics consume very few calories,
and bulimics consume lots
– which makes their behaviour “abnormal”
The statistical definition
The spread is measured by standard deviation
68% of the population fall between 1 SD either side of the mean and 95% fall between 2 SD.
Thus, scores outside this range are unusual, therefore 2.5% fall below it and 2.5% above it.
The IQ intelligence quotient is often given as an example of the working of this definition.
IQ is normally distributed across the population and anyone outside the normal limits is said to have an abnormal IQ.
IQ has a standard deviation of 15 and a mean of 100. One standard deviation either side would be from 85 to 115, two
standard deviations either side is from 70-130, this is where normal ends.
An IQ score of 130 and above is abnormally high IQ score, and the same for an IQ score of 70 and below
Only 2.2% of the IQ score is above 130 and below 70.
This is further illustrated by the fact that having an IQ below 70 is one of the criteria's for mental disorder.
Normal Distribution
Abnormality is seen as anything that is
statistically infrequent
It helps to know about normal distribution, a characteristic of behaviour is seen as
normally distributed if the mean average, mode and median all fall in the same
In the middle of the scores this simply means that there are roughly the same
number of scores on each side of the average - the scores are normally distributed
around the average
Any score that is two standard deviations or more away from the mean denotes
• This is not only applied to IQ but to other mental health criteria
For example: DASS (depression, anxiety, and stress scale) uses a questionnaire to measure
depression, anxiety and stress, a very high score would be considered abnormal and in
need for treatment, the DASS score would be expected to fall in the middle to be
considered normal.
Knowing that the data is normally distributed
means that anyone a long way away outside the
average could be regards as abnormal.
Can you?
Have a go at describing the statistical
infrequency definition in your own words
Lets have a discussion!
Is this definition of abnormality suitable in terms of
People who are extremes either end – are they
What might the limitations of this definition be?
• It gives a quantitative measure that is objective.
• On a practical level - can be useful as evidence in
support of requests for assistance and funding for
those identified
• Having a number is not only useful because it is seen
as objective but also because it is accepted as more
• Abnormal in both a statistical and a mental health sense may not be
undesirable - an IQ score of 130+ is likely to be seen as desirable
• BUT… IQ scores of 130+ are infrequent but you wouldn’t call these
people abnormal:
Albert Einstein
Sharon Stone
Charles Darwin
Bill Gates
Abraham Lincoln
Hillary Clinton
Sir Isaac Newton
• There are statistically frequent behaviours
which are considered as abnormal
• What about left-handedness?
• Abnormal behaviour is not rare, most people
are likely to show abnormal behaviour some
time in their life.
An Example
 Some one who fits the criteria for mental retardation
but are living happy and independent lives
 Sarah and Michelle are both sisters, Sarah has an IQ of
69 and Michelle has an IQ of 70, both work on a full
time basis at their Local Tesco’s, Sarah is thinking of
going back to college and do an NVQ qualification,
whilst Michelle is expecting her first child and wants to
become a full-time mum.
 Cut off point is an IQ score of 70, how can we justify
someone as being abnormal if they have a score of 69?
Deviation from Social Norms
What are social norms?
Queuing for
one hour in the
Post Office
Being covered
head to toe in
Stealing from
the local shop
Not standing
too close to
someone when
you speak
Hearing voices
in our head
Counting the
number of
times you chew
your food
Being part of a
gay community
Being a member
of a church group
that meets daily
Having big
holes in your
clothes when
its cold.
Saying please
and thank you
Wearing a
diving suit
when walking
down the road
Deviation from social norms
• Every society has accepted standards
of behaviour – can be based on law, or
just generally accepted by society
• Social norms allow for the regulation
of normal behaviour.
• One approach to defining abnormality
is to consider deviations from the
social norm as an indicator of
abnormal behaviour.
Written social norms
• People who commit
crimes are considered
abnormal, because they
are breaking the rules of
the legal system
• All people who are in
prison are considered
abnormal by this
definition e.g. murderers,
fraudsters, paedophiles,
robbers, burglars and
drunk drivers.
Unwritten Social Norms
• E.g. holding doors open for people rather than
letting it slam into their face
Can you think of any others?
Unwritten social norms
Being polite
Opening doors for people
Not hearing voices
Not washing your hands 50
times a day
Queuing in shops
Not standing too close to
people when talking
Wearing clothes when walking
around outside
These are just a few examples which give an
indication of normal/abnormal behaviour
What is considered a deviation from a
social norm?
Can you?
Have a go at describing the social norms
definition of abnormality in your own words…
The effect of culture
• Different cultures/societies will have
different social norms – would define
abnormality differently
• For example, hearing voices in one culture
would be seen as being connected to
spirits, whereas in another –
• In the Chippewa culture, a native
American culture, visions of Thunderbirds
- a great bird, are regarded as a great
honour. However, western psychiatry
would view these visions as a symptom
of schizophrenia (hallucinations).
Genital Retraction Syndrome (Koro)
• A condition in which an individual is overcome
with the belief that his/her external genitals are
retracting into the body, shrinking, or in some
male cases, may be imminently removed or
disappear. Beliefs in many instances assert such a
physical change to the individual that the result is
often fatal.
• Culturally specific (East Asia) – how would we
diagnose this here?
The effect of context
• The situation and context for the behaviour
are both important, a behaviour might be
abnormal in one context but normal in
• When would these instances be considered to
be normal/abnormal?
The effect of historical context
• What was considered as the norm many years ago might have changed
• E.G - becoming pregnant outside wedlock was considered evidence as a
mental health problem 100 years ago, women could have been put into an
institution because of it
• Homosexuality in 1980 DSM
Moral insanity
Slaves experienced an irrational desire
to run away
Middle class women were sexually
attracted to working class men
Women who inherited money spent
it on themselves rather than male relatives
Deviation from social norms
Two disorders that can be classified using the
Deviation from Social Norms definition are:
Obsessive Compulsive Disorder
Pick one of these and discuss with your partner how they
relate to the definition of abnormality.
Then join with another pair and share your ideas about your
Strengths and Weaknesses
Using the cards, decide which of the points are
related to which definition of abnormality
Then decide on which are strengths and which are
weaknesses of each definition
Copy the points into the table provided
Exam Question
Have a go at structuring an answer for a
12 mark exam question on the two
definitions of abnormality
Dr Padawi wishes to explain to a group of
hospital volunteers how psychiatrists try to
make decisions about abnormality. Dr
Padawi decides to start by explaining how
abnormality is defined.
Describe and evaluate two definitions of
abnormality. In your answer you must
refer to how Dr Padawi might explain
definitions of abnormality to the
volunteers. (12 marks)
Text book
• Introduction to clinical psychology - Read
pages 214-218
It re-states what you will be covering (see
• Two definitions of abnormality reading
• Pages 229-245 – read and make notes
• Be ready to ask/answer questions next lesson