A superiority complex is a psychological defense mechanism that compensates for an inferiority complex. The term was coined by Alfred Adler as part of his school of individual psychology. It was introduced in his series of books, including "Understanding Human Nature" and "Social Interest".
Definition by Adler
"We should not be astonished if in the cases where we see an inferiority [feeling] complex we find a superiority complex more or less hidden. On the other hand, if we inquire into a superiority complex and study its continuity, we can always find a more or less hidden inferiority [feeling] complex."
"If a person is a show-off, it is only because she or he feels inferior because she or he does not feel strong enough to compete with others on the useful side of life. That is why she or he stays on the useless side. She or he is not in harmony with society. It seems to be a trait of human nature that when individuals – both children and adults – feel weak, they want to solve the problems of life in such a way as to obtain personal superiority without any admixture of social interest. A superiority complex is a second phase. It is a compensation for the inferiority [feeling] complex."
"The superiority complex is one of the ways that a person with an inferiority complex may use as a method of escape from her or his difficulties. She or he assumes that she or he is superior when she or he is not, and this false success compensates her or him for the state of inferiority which she or he cannot bear. The normal person does not have a superiority complex, she or he does not even have a sense of superiority. She or he has the striving to be superior in the sense that we all have ambition to be successful; but so long as this striving is expressed in work it does not lead to false valuations, which are at the root of mental disease."
From Alfred Adler's point of view, an individual faced with a task wants to overcome or master the task. This is known as striving for superiority. For a well-adapted individual, this striving is not for personal superiority over others, but an overcoming of the task, or finding useful answers to questions in life. When faced with the task, the individual will experience a feeling of inferiority or a sense that the current situation is not as good as it could be. This feeling is similar to stress. If the individual has not been properly trained, the task may seem too much to overcome and lead to an exaggerated feeling of inferiority, or intense anxiety. The individual may, after several unsuccessful attempts to accomplish the task, give up on mastering the task, experiencing the inferiority complex, or a depressed state. The individual may also make several attempts at solving the problem and find a solution to the problem that causes problems in other areas. An individual who answers the question "How can I be thin?" by not eating will become thin, but at the cost over their overall health.
An individual who is not properly trained to answer life's problems may turn from striving for superiority in useful ways to that of a personal superiority at all cost. If an individual cannot be better than another on their own merit, they will attempt to tear down another person or group to maintain their superior position.
Interpretations in modern psychology
Other authors have argued that the superiority and inferiority complex cannot both be found in the same individual since an individual with a superiority complex truly believes that he or she is superior to others. An inferiority complex may manifest with the behaviors that are intended to show others that one is superior; such as expensive material possessions, or an obsession with vanity and appearances. They express themselves as superior because they lack feelings of adequacy. Superiority complex sufferers do not always care about image or vanity, since they have innate feelings of superiority and thus do not usually concern themselves with proving their superiority to others. The term "superiority complex", in everyday usage, refers to an overly high opinion of oneself. In psychology, it refers not to a belief, but a pattern of behaviors expressing the belief that one is superior. Similarly, one with an inferiority complex would act as if they were inferior, or not up to the task.
Those exhibiting the superiority complex have a self-image of supremacy. Those with superiority complexes may garner a negative image in those around them, as they are not concerned with the opinions of others about themselves. This is responsible for the paradox in which those with an inferiority complex are the ones who present themselves in the best light possible; while those with a superiority complex may not attempt to make themselves look good. This may give off an image that others may consider inferior. This is responsible for the misconception that those with an inferiority complex are meek and mild, but the complex is not defined by the behavior of the individual but by the self-image of the individual. Not that a person with a superiority complex will not express their superiority to others, only that they do not feel the need to do so. They may speak as if they are all-knowing and better than others. But ultimately they do not care if others think so or not, and will not care if others tell them so. They simply won't listen to, and don't care about, those who disagree. In this regard, it is much like the cognitive bias known as illusory superiority. This is juxtaposed to an inferiority complex where if their knowledge, accuracy, superiority or etc. is challenged, the individual will not stop in their attempts to prove such things until the dissenting party accepts their opinion (or whatever issue it may be). Again this is another reason that those with inferiority complexes are often mistaken for having superiority complexes when they must express and maintain their superiority in the eyes of others. Many fail to recognize that this is a trait of those of low self-opinion who care deeply about the opinion of others, not of those who feel superior and have high self-esteem and do not care at all about the opinion of others.