Perception and behaviors are effected by expectations when people are aware of a probable or desired outcome. This include demand characteristics where people behave the way expected of them, the halo effect where people perfomance is judged on their reputation, the Hawthorne effect where people become more productive whene changes are made to their environment, the pygmalion effect, the placebo effect and Rosenthal effect where people are treated differently based on expectations of how they will perfom.