Which effect states that supervisors' attitudes and expectations of employees and how they treat them largely determine employees' performance?

Pygmalion Effect

Explanation:

The Pygmalion effect explains to managers the methods they can employ to achieve better performances from average or low performers.

The Pygmalion effect implies that what someone expects from another person in terms of their performance shapes the behavior of that person in such a way that they achieve those expectations from them.

The basic idea behind the Pygmalion effect is that when the leaders increase their expectations of the performance of their subordinates, it spurs the subordinates to perform better. Consequently, there will be a better performance when the expectations are high and worse performance when the expectations are low.