Definition : Statistical Infrequency

Statistical Infrequency / Outline (A01) / Weaknesses (Limitations)
By definition abnormality means deviating 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 ‘abnormal’.
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.
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”.
Potential Exam Question:
1. Describe one definition of abnormality (3 marks)
2. Describe the statistical infrequency definition of abnormality (6 marks)
3. Discuss statistical infrequency definition of abnormality and their limitations (18 marks) /  One weakness of the statistical infrequency definition is that it does not classify whether all behaviour is undesirable. The main objection to this approach is that there are many abnormal behaviours that are quite desirable. E.g., very few people have an IQ over 150, yet would not want to suggest that this is undesirable. Equally there are some normal behaviours that are undesirable such as depression is relatively common, yet it is undesirable. Therefore using statistical infrequency to define abnormality means that we are unable to distinguish between desirable and undesirable behaviours. In order to identify behaviours that need treatment, there needs to be a means of identifying infrequent and undesirable behaviours
 A further weakness of the definition of statistical infrequency is knowing where the cut off point is. How far from the norm do you have to be classified as being abnormal? For example, we might look at symptoms of depression and decide that any symptoms experienced by 80% of the population are normal (e.g., not sleeping well or poor appetite) but those symptoms experienced by only 20% would be classed as normal (e.g., thoughts of suicide)
This suggests that the cut off point is inevitably subjectively determined but is important for deciding who gets treatment.
 A weakness of the statistical infrequency definition is that it is culturally relative. The reason for this is because one symptom of schizophrenia is claiming to hear voices. However, this is regarded as desirable in some cultures. Lee (1969) found that many Zulu women reported screaming to themselves for days or weeks as a response to unhappiness. Such behaviours would be statistically infrequent in the UK, yet very frequent in Zulu women
This suggests that it is difficult to apply this definition to all cultures universally.
 Another weakness is knowing where the draw the line. Another difficulty with the statistical approach is deciding where the cut off point is for defining abnormality. There is no agreed point on a scale at which behaviour is classified as abnormal and, in any case, it is unlikely that abnormal states can be categorised in such black and white terms. E.g., there are degrees of severity of depression.
 Another weakness of the definition is that there are gender differences. The definition is good when a psychological disorder has been diagnosed by a psychologist, but not if they have been diagnosed by a non-professional person. For example, females are more likely than males to consult their doctor for anxiety problems, whereas males are more likely to bottle up their anxiety, or try to deal with it in physical terms such as vigorous sporting activities. It is believed that this is caused by males being socialised to distance themselves from their emotions
This suggests that the definition cannot be applied universally.
 A final weakness of the statistical infrequency definition is that there is contradictory evidencefrom Angst. Problems of depression or anxiety are classified as psychological disorders because they adversely effect normal functioning. However, in statistical terms this is not useful. Angst (1992) for example, has found that one in 20 Americans is severely depressed and that there is a 1 in 10 chance of having a serious depressive episode at least once in your life time. Furthermore, 47% in the USA had suffered fromychological disorder.

Additional A01 and A02 Material

You can use the following material below as either A01 or Ao2 material. Remember if you use it as A02 you need to jam sandwich it so it has a top and bottom layer of bread.