The Pygmalion effect is the phenomenon where higher expectations lead to improved performance — the belief others hold about you can become a self-fulfilling prophecy.

The Rosenthal-Jacobson Study

In 1968, researchers told elementary school teachers that certain students had been identified by testing as intellectual "bloomers" about to show dramatic growth. In reality, the students were selected randomly. By year's end, the "bloomers" showed significantly greater IQ gains than their classmates — driven entirely by the changed behavior of teachers who expected more from them.

Mechanisms

• Teachers gave bloomers more time to answer questions
• Teachers gave more challenging material
• Teachers' nonverbal behavior communicated higher confidence
• Students internalized the belief and acted accordingly

Leadership Implication

Your expectations of your team are not invisible — they leak through behavior, tone, assignment of work, and how you respond to setbacks. High expectations, consistently communicated, are a genuine performance lever.

Reverse: Golem Effect

Low expectations produce the same self-fulfilling result in reverse. Be careful what you signal about what you think people are capable of.

Reference:

Wikipedia: Pygmalion Effect

https://en.wikipedia.org/wiki/Pygmalion_effect