Illusory superiority is a cognitive bias that causes people to overestimate their positive qualities and abilities and to underestimate their negative qualities, relative to others. This is evident in a variety of areas including intelligence, performance on tasks or tests and the possession of desirable characteristics or personality traits. It is one of many positive illusions relating to the self, and is a phenomenon studied in social psychology.
It is often referred to as the above average effect. Other terms include superiority bias, leniency error, sense of relative superiority, and the Lake Wobegon effect (named after Garrison Keillor’s fictional town where “all the children are above average”).
Illusory superiority has been found in individuals’ comparisons of themselves with others in a wide variety of different aspects of life, including performance in academic circumstances (such as class performance, exams and overall intelligence), in working environments (for example in job performance), and in social settings (for example in estimating one’s popularity, or the extent to which one posesses desirable personality traits, such as honesty or confidence), as well as everyday abilities requiring particular skill.
For illusory superiority to be demonstrated by social comparison, two logical hurdles have to be overcome. Some psychological experiments require subjects to compare themselves to an average peer. If we interpret the average as the mean, then it is logically possible for nearly all of the set to be above average if the distribution of abilities is highly skewed. Hence experiments usually compare subjects to the median of the peer group, since by definition it is impossible for most of the set to do better than the median.
A further problem in inferring inconsistency is that subjects might interpret the question in different ways, so it is logically possible that a majority of them are, for example, more generous than the rest of the group each on their own understanding of generosity.