Definitions of Abnormal Behaviour: Statistical Infrequency and Deviation from Social Norms

1. Home Learning For lesson 1 Definitions of Abnormal Behaviour:Statistical Infrequency and Deviation from Social Norms Specification: Describe the statistical infrequency and the ‘social norms’ definition of abnormality. Evaluate these definitions in terms of their suitability as definitions of abnormality.

2. Definitions of abnormalbehaviour • Defining a person or behaviour as ‘abnormal’ implies something undesirable and requiring change • Therefore, we must be careful how we use the term • However, psychologists do need methods for distinguishing ‘abnormal’ where a person potentially requires some form of intervention, from ‘normal’

3. 4 ways of defining dysfunctional behaviour • 1) Deviation from social norms • 2) Statistical Infrequency • 3) Failure to function • 4) deviation from ideal mental health

4. Statistical Infrequency • Under this definition, a person’s trait, thinking or behaviour is classified as abnormal if it is rare or statistically unusual. • With this definition it is necessary to be clear about how rare a trait or behaviour needs to be before we class it as abnormal

5. Mean IQ in the population is 100pts. The further from 100 you look, the fewer people you find Statistical Infrequency www.psychlotron.org.uk frequency 70 100 130 IQ Scores

6. A very small subset of the population (<2.2%) have an IQ below 70pts. Such people are statistically rare. We regard them as having abnormally low IQs Statistical Infrequency www.psychlotron.org.uk Two Standard deviations frequency One Standard deviation 70 100 130 IQ Scores

7. SUMMARY: Statistical Infrequency: • Requires a behaviour/trait to be quantifiable • Requires a behaviour/trait to be normally distributed within the population- bell curve on a graph. • The mean for the behaviour/trait can be calculated along with standard deviations away from this point • Abnormal behaviours/traits are those which fall into the top and bottom 2.5%: typically more than 2 standard deviations away from the mean.

8. Deviation from Social Norms • 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 • E.g. not standing too close to someone when they are talking. • Social norms allow for the regulation of normal behaviour. • One approach to defining abnormal behaviouris to consider deviations from the social norm as an indicator of dysfunctional behaviour.

9. Deviation from Social Norms • Examples of social norms include • 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 • Wear clothes when walking around outside • These are just a few example. If someone was not acting within these social norms, their behaviour would be defined as abnormal.