Negative discrimination has always existed, we have always had an opinion about the other individual, despite the fact that it was often without any background knowledge. It was in the first half of the twentieth century that the scientific, social psychological study of prejudice began in the United States, dominated by the antagonism between whites and blacks. It was at this time that human society came to realise that the problem was a global one, and that it was essential to examine it, starting, among other things, from the massacres of the Second World War, which were partly the result of prejudice. Unfortunately, however, we do not need to go back to the great events of history to realise that prejudice has serious consequences. In our everyday lives, we are also confronted with a plethora of cases of crime, discrimination and conflict based on an image of the other person that is based on incomplete information.
Although the image of a world free of prejudice may be a utopia, these types of feelings and attitudes can and must be dealt with, but above all it is very important to map the situation and to examine it scientifically.