The Pygmalion Effect explains that
people tend to perform up to the level that others expect of them. This effect explains why our relationships are usually self-fulfilling prophecies. Once you set expectations for somebody, that
person will tend to live up to that expectation, whether it's good or
bad.
But the Pygmalion Effect also applies to your personal growth. Your beliefs about yourself impact your actions towards others, which influence their beliefs about you and their actions towards you.
Positive
expectations influence performance positively, and negative
expectations influence performance negatively. ... In educational circles, this has been termed the Pygmalion Effect, or more colloquially, a
self-fulfilling prophecy.