# What is meant by statistical deviation as a definition of abnormality?

Behaviours, emotional reactions and patterns of thinking which are statistically rare (atypical) or deviate from the statistical average or norm are classified as abnormal. The statistical definition hinges on the idea that abnormality can be measured using quantitative data and thus one individual can be compared with another. Statistical norms are established using a normal distribution curve which illustrates the fact that most people, (approx 95%) score between one and two standard deviation above or below the mean average. This leaves just over 2% of people who score unusually high or low and these people would be classed as abnormal because they are not typical of most people.

When diagnosing depression for example, a structured interview or questionnaire including closed questions may be used and quantitative data can be derived; once the practitioner has calculated the individual’s ‘score’, this can be compared to statistical norms and a decision made about whether the person has a score which is high/low enough to be classed as abnormal.

With regard to intelligence the standard deviation is 15 and the average is 100, this means that anyone who scores over 130 or under 70 will be classed as abnormal since these scores are two standard deviations above and below the mean.

defining abnormality (1)

To prepare for your class, you will also need to to consult the following handout:…Statistical infrequency handout.doc

Abnormality "Outline and evaluate two definitions of abnormality: statistical infrequency and deviation from social norms." The term "abnormality" is defined as 'deviation from a norm or standard' and in psychology, it is essential to look at what abnormality is. Several ideas have developed for its definition, none of which are entirely apposite since the best way to define abnormality may be a combination of the varying ideas. Two definitions of abnormality that are probably most obvious and most often used are 'statistical infrequency' and 'deviation from social norms'. These define that abnormality is rare, i.e. the majority of the population are not abnormal and that a small minority are, and also that a person who is abnormal deviates from social norms, meaning that the person differs from or does not conform to what is socially accepted. Statistical infrequency is based on the idea that particular behaviours are statistically rare since if few people show a certain kind of thinking or behaviour, it is deemed as abnormal. When any aspect of human behaviour is measured, e.g. ...read more.

It is also thought that some mental illnesses are on the increase (such as depression and certain anxiety disorders); consequently, this behaviour is not rare and thus is not statistically infrequent. Another discrepancy that might be found within the statistical approach to abnormality lies with the statistical definitions since they directly correlate to a standard set by a particular population. This standard will not automatically apply to all cultures, or even to people in different age groups or genders. For example, children are far more likely to be afraid of the supernatural or monsters since this is a rational fear for children to have because we accept it as normal for their age, whereas for adults, this kind of behaviour is much less likely to be accepted. Deviation from social norms is behaviour that does not follow socially accepted patterns and because this behaviour violates and appears to condemn society, it is regarded as abnormal. The unwritten rules of society indicate that humans must behave in a socially accepted way by not breaking with conventions and by doing as is expected. ...read more.

Nonetheless, some might argue that the high principles motivating someone to be socially deviant are equally abnormal as someone wishing not to conform anyway. For the 'deviation of social norms' definition to be less flawed in the case of abnormality, it would also be appropriate to take into account the time and context of the supposedly social deviant behaviour. For example, wearing beach clothes would be completely inapt while out shopping on the high street whereas this kind of attire would be well suited to the beach or a swimming pool. Both definitions have their faults and limitations; nevertheless, it would be a very laborious task to ascribe an exact and pertinent definition to abnormality, especially in the terms of psychology. As there is such an abundance of necessities to take into account along with the effects of culture relativism and the changing times, it is probably true to say abnormality is a constantly changing definition and that it is wholly dependent on society's view of what is normal and what is not. Whether society and/or the majority are morally correct to decide these boundaries, is another question. Michelle Lockwood ...read more.

### What is statistical infrequency as a definition of abnormality?

Statistical Infrequency is a definition of abnormality. According to this definition, a behaviour is seen as abnormal if it is statistically uncommon, or not seen very often in society.

### What is statistical deviation psychology?

Statistical deviation denotes the percent of variation that a score deviates from the statistical norm. Statistical deviation refers to how large a group of a selected population sample differs from the remainder of the same population.

### What are the 4 definitions of abnormality?

WHAT YOU NEED TO KNOW. Definitions of Abnormality: Statistical Infrequency, Deviation from Social Norms, Failure to Function Adequately, Deviation from Ideal Mental Health.

### What is statistical criteria of abnormality?

Statistical Infrequency. Under this definition of abnormality, a person's trait, thinking or behavior 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 behavior needs to be before we class it as abnormal.