The Ego Awareness Movement, the project of a writer who publishes only as Anon I mus, established both itself and World Ego Awareness Day in 2018 and fixed the observance on May 11. A capture of the movement's page taken a month before the first observance called it a first-ever event.
A website in February
That site's first page carries a published timestamp of 7 February 2018 and the heading What is the Ego. Everything the movement does follows from what it says there.
The ego is not narcissism, the page argues, though it grants that is how our society commonly describes it. It calls the ego a primal function of the mind that developed for survival. A child, it says, begins building one at about the age of two.


