Stigma (literally, "label") - an extremely strong social label, which completely changes the attitude towards others and themselves, forcing refers to a person only as the bearer of an undesirable quality. There are various attempts stigma definition as a phenomenon. However, numerous studies allow us to say: every time when it comes to stigma definition, we can see three common features - the three rules of stigma:

1. Differences between people are stressed and are considered important. All people are different from each other on the set of criteria. Most differences are not of fundamental importance (passport number, eye color, presence of cytomegalovirus), but if people stigmatize, their differences are viewed as important and socially significant (skin color, the presence of HIV). With respect to these differences people immediately divided into opposing categories (black and white, blind and sighted, HIV-positive and HIV-negative).

2. People with differences attributed negative qualities. We often look at people's stereotype. All of our stereotypes about other people are wrong, but they can be neutral or even positive, for example: all women love to take care of the children, all Italians are very emotional. But when it comes to stigma, the differences are considered to be something negative, such as: all people with HIV are dangerous, people with HIV want to infect others with HIV become infected because of immoral behavior, etc. That is, people who are together only one quality (presence of virus in the blood), attributed negative qualities to the virus are not connected: the danger to others, the desire to cause harm, immoral behavior.

Sometimes the attribution of undesirable features may outwardly appear benevolent and even opposite stigma. For example: all HIV-positive need help and support them throughout. But this is also the attribution of negative qualities, in this phrase means that people with HIV - the victim, they are combining all their problems are associated only with HIV.

3. People are divided into "us" and "them". When we have someone stigmatize, we think in terms of "we" and "them".

This division suggests that "they" are not quite people, at least, not people like "us". This is often evident in the language, for example, no one speaks flu-infected person because the person with the flu - one of "us." But while people with HIV is constantly referred to as HIV-positive, bringing thus the whole personality of the person to his disease.

If people find some sort of distinction is very important, is credited to people who it is, the negative traits, and can easily be divided based on people on the "us" and "them" - we are talking about stigma.