Normality (also known as normalcy) is the state of being "normal", as opposed to being deviant, eccentric or unusual. Behavior can be normal for an individual (intrapersonal normality) when it is consistent with the most common behaviour for that person. Normal is also used to describe individual behaviour that conforms to the most common behaviour in society (known as conformity). Definitions of normality vary by person, time, place, and situation – it changes along with changing societal standards and norms. Normal behavior is often only recognized in contrast to abnormality. In its simplest form, normality is seen as good while abnormality is seen as bad. Someone being seen as "normal" or "not normal" can have social ramifications, such as being included, excluded or stigmatized by larger society.
Normality has been functionally and differentially defined by a vast number of disciplines, so there is not one single definition.
In general, 'normal' refers to a lack of significant deviation from the average. The word normal is used in a more narrow sense in mathematics, where a normal distribution describes a population whose characteristics centers around the average or the norm. When looking at a specific behaviour, such as the frequency of lying, a researcher may use a Gaussian bell curve to plot all reactions, and a normal reaction would be within one standard deviation, or the most average 68.3%. However, this mathematical model only holds for one particular trait at a time, since, for example, the probability of a single individual being within one standard deviation for 36 independent variables would be one in a million. In statistics, normal is often arbitrarily considered anything that falls within about 1.96 standard deviations of the mean, or the most average 95% (see 1.96). The probability of an individual being within 1.96 standard deviations for 269 independent variables is approximately one in a million. For only 59 independent variables, the probability is just under 5%. Under this definition of normal, it is abnormal to be normal for 59 independent variables.
The French sociologist Émile Durkheim indicated in his Rules of the Sociological Method that it was necessary for the sociological method to offer parameters to distinguish normality from pathology or abnormality. He suggested that behaviors or "social facts" which are present in the majority of cases are normal, and exceptions to that behavior indicate pathology. Durkheim's model of normality further explained that the most frequent or general behaviors, and thus the most normal behaviors, will persist through transition periods in society. Crime, for instance, exists under every society through every time period, and so should be considered normal. There is a two-fold version of normality; behaviors considered normal on a societal level may still be considered pathological on an individual level. On the individual level, people who violate social norms, such as criminals, will invite a punishment from others in the society.