In psychology, egocentrism is defined as a) the incomplete differentiation of the self and the world, including other people and b) the tendency to perceive, understand and interpret the world in terms of the self.

egocentric: not capable of differentiating one's self and others or the world

The term derives from the Greek ego, meaning "I". An egocentric person has a limited theory of mind, cannot fully "put himself in other peoples' shoes," and believes everyone sees what he/she sees (or that what he/she sees, in some way, exceeds what others see).

egocentrism: I-centered, not able to realize that others perceive the world differently

It appears that this egocentric stance towards the world is present mostly in younger children. They are unable to separate their own beliefs, thoughts and ideas from others. For example, if a child sees that there is candy in a box, he assumes that someone else walking into the room also knows that there is candy in that box. He implicitly reasons that "since I know it, you should too". As stated previously this may be rooted in the limitations in the child's theory of mind skills.

theory of mind: the ability to attribute mental states—beliefs, intents, desires, pretending, knowledge, etc.—to oneself and others and to understand that others have beliefs, desires and intentions that are different from one's own

However, it does not mean that children are unable to put themselves in someone else's shoes. As far as feelings are concerned, it is shown that children exhibit empathy early on and are able to cooperate with others and be aware of their needs and wants.

egocentrism should not be confused with lack of empathy

Jean Piaget (1896-1980) claimed that young children are egocentric. This does not mean that they are selfish, but that they do not have the mental ability to understand that other people may have different opinions and beliefs from themselves.

egocentric is not the same as selfish

With his colleague Barbel Inhelder, Piaget did a test to investigate egocentrism called the three mountains problem (Piaget & Inhelder 1948/1956). He put children in front of a simple plaster mountain range and then asked them to pick from four pictures the view that he, Piaget, would see. Younger children before age 7, during the so-called pre-operational stage, picked the picture of the view they themselves saw and were therefore found to lack the ability to appreciate a viewpoint different from their own. In other words, their way of reasoning was egocentric. Only when entering the so-called concrete-operational stage at age 7-12, children became capable of decentring and could appreciate viewpoints other than their own. In other words, they were capable of cognitive perspective-taking.

cognitive perspective-taking is essential in breaking away from the egocentric pre-operational stage and into the concrete-operational stage during youth life

However, the mountains test has been criticized for judging only the child's visuo-spatial awareness, rather than egocentrism. A follow up study involving police dolls showed that even young children were able to correctly say what the interviewer would see. It is thought that Piaget overestimated the levels of egocentrism in children.

egocentrism should not be confused with lack of ability to exhibit one's visuo-spatial awareness

Egocentrism is thus the child's inability to see other peoples' viewpoints. The child at this stage of cognitive development assumes that their view of the world is the same as other people's, e.g. a little girl covers her eyes and says 'mummy you can't see me now, can you?'