The Pygmalion effect refers to the phenomenon in which the greater the expectation placed upon people, (often children or students or employees,) the better they perform. The effect is named after Pygmalion, a Cypriot sculptor in a narrative by Ovid in Greek mythology, who fell in love with a female statue he had carved out of ivory.
The Pygmalion effect is a form of self-fulfilling prophecy, and, in this respect, people with poor expectations internalize their negative label, and those with positive labels succeed accordingly.