The Psychology of Abnormal Behavior: Understanding the Criteria & Causes of Abnormal Behavior

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  1. 0:05 What Is Abnormal Behavior?
  2. 1:07 Culture & Abnormality
  3. 2:04 Criteria of Abnormality
  4. 4:41 Causes of Abnormal Behavior
  5. 5:49 Lesson Summary
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Taught by

Natalie Boyd

Natalie is a teacher and holds an MA in English Education and is in progress on her PhD in psychology.

What is abnormal behavior? In this lesson, we will look at how psychologists define abnormality, the criteria they use to identify it, and some common causes of abnormal behavior.

What is Abnormal Behavior?

Cindy is sitting in class while the professor gives a lecture. The content of the lecture is pretty boring, and several students struggle to pay attention. Most of them at least pretend to be listening to the professor, but not Cindy. Cindy taps her fingers on the desk very loudly. She groans and rolls her eyes when the professor goes off on a tangent. Eventually, she even gets up and starts to dance to music only she can hear.

Abnormal behavior is behavior that deviates from what is expected and normal. The study of abnormal behavior is called abnormal psychology.

But what exactly constitutes abnormal behavior? Most people would probably agree that when Cindy stands up in the middle of class and dances to an imaginary playlist, she's displaying abnormal behavior. But what about groaning and rolling her eyes? What about tapping her fingers on the desk? Are these abnormal, too, or still within the realm of what's normal?

Culture and Abnormality

Abnormal behavior is sometimes hard to define, for several reasons. First of all, people have to agree on what's normal. This can vary widely both within and outside cultures. For example, when British settlers first moved to America, they were used to fencing land and raising livestock on it. They had a good idea of the difference between public and private land.

However, the American Indians viewed land as a public thing and didn't understand the concept of fencing parts off. Further, they used the land to raise crops, not livestock. To the Indians, the white man's way of fencing land and keeping animals in pens seemed very abnormal!

Culture isn't just about what happened in early America. A woman walking down a street in America without a top on would be considered to be acting abnormally. However, in a culture where bare-breasted women are normal, a woman with a top on might be seen as abnormal.

Criteria of Abnormality

In general, psychologists look at four different criteria for defining abnormal behavior. Each has its strengths, and each has its problems.

The first criterion is violation of social norms. Behavior that goes against what is considered normal by society is abnormal. As we just saw, culture plays a role in social norms, as does age. A man who takes off all his clothes and jumps in a fountain is likely to be seen as weird, whereas a three-year-old who does it might just be seen as cute.

Another criterion for identifying abnormal behavior is statistical rarity. A person who has an extremely low IQ, for example, might be classified with some type of mental retardation. Because there is only a small percentage of the population with mental retardation, it is rare and therefore abnormal. Of course, the problem with statistical rarity is that people who are exceptionally intelligent are just as rare as those with mental retardation. So according to this criterion, Albert Einstein would be abnormal.

A third criterion of abnormal behavior is personal distress. When we engage in abnormal behavior, the cause (and sometimes, result) of our behavior can be distress. A good example of this is obsessive-compulsive disorder, where anxiety about something can lead to compulsive behaviors meant to relieve that distress. The problem with personal distress, though, is that some people with mental illness do not feel distress, such as people with antisocial personality disorder who have an underdeveloped conscience.

The final criterion for defining abnormal behavior is maladaptive behavior. Is the behavior likely to hurt the person or someone else? Whether it is physical harm or social harm, such as losing a job or the respect of your peers, maladaptive behavior leads to some type of harm.

Because each of these criteria has strengths and weaknesses, most psychologists use all of them to get a picture of abnormal behavior. For example, Cindy's behavior in class is maladaptive because it could lead to her professor marking down her grade. It is also a clear violation of social norms, which say that students in class sit quietly and at least pretend to listen to the professor. It's probably statistically rare that someone would get up in class and start dancing to music that no one else can hear.

But what if Cindy doesn't experience personal distress at it? Well, since it fulfills three of the four criteria, most psychologists would agree that it is abnormal behavior, even if it does not cause personal distress.

Causes of Abnormal Behavior

There are many things that can cause abnormal behavior. Biological and psychological issues can both play a part in abnormality. A few general causes of abnormal behavior include the following:

  1. Relief from distress. Everyone has felt anxiety or stress at some point. Some people cope with these feelings by engaging in behaviors that some people would consider odd. For example, a person who feels anxious about germs might wash their hands over and over again.
  2. Lack of thought or feeling. Some people don't think their actions through or don't experience the same types of feelings as others. For example, a person who does not feel embarrassment might say things that are inappropriate without the censor of embarrassment to stop them.
  3. Perceiving the world differently. Some people experience hallucinations, which feel as real to them as senses from the real world. For example, someone with schizophrenia might hear voices in their head that sound as real as the voices from people around them. Their reactions to the hallucinations would be considered odd, indeed.

Lesson Summary

Abnormal behavior is any behavior that deviates from what is considered normal. There are four general criteria that psychologists use to identify abnormal behavior: violation of social norms, statistical rarity, personal distress, and maladaptive behavior. Though there are many causes of abnormal behavior, three common causes are relief from distress, lack of thought or feeling, and perceiving the world differently.

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