We mislead ourselves all day long. Such self-serving biases we undertake to cheat ourselves in order to mislead others and construct social advantage. Psychologists have identified several ways of fooling ourselves like biased information-gathering, biased reasoning and biased recollections. We seek information only that supports what we want to believe and avoid that which we do not.
One of the most common types of self-deception is self-enhancement. We overestimate our good qualities because it makes us feel good. Self-enhancement boosts motivation, leading to greater accomplishment. If getting motivated is our goal, then we could do that without reality distortion. Self-deception has evolved for the purpose of other deception.
Overconfidence about one’s self intelligence neither leads to better mental health or academic performance, but self-deception begets social advantage. Most of us see good self-esteem and enhanced motivation is a reason enough for self-enhancement to evolve. In the long run overconfidence may backfire.
It is not that there is one part of us deliberately fooling another part of us that is the “self.” If you need to convince somebody of something, if your career or social success depends on persuasion, then the first person who needs to be convinced is yourself. On the defensive side, whenever anyone tries to convince you of something, think about what might be motivating that person. Even if he is not lying to you, he may be deceiving both you and himself.