If your teacher thinks you are dumb, you will be.
The Golem Effect is where if someone has a negative opinion of you, you will perform worse for them than you would have otherwise. The Pygmalion Effect is the opposite – a positive opinion will result in your overachieving. Teaching is the most obvious environment where this has a profound effect. If you have two equal students, but the teacher for some reason thinks one is clever and the other stupid, they are likely to perform very differently. Together the pygmalion and golem effects are known as the Observer-Expectancy Effect.
There are many experiments which have shown this effect, such as Eden and Shani’s, in the early 1980s. They gave instructors of a commando training course the “command potential” of each of the soldiers they were teaching. The command potential, of which the soldiers were unaware, was either Regular, Unknown or High. After a 15 week course there was a battery of tests, both theory and practical. Those with a regular potential scored an average of 65%. Those with a high potential averaged 80%.
Not a surprising result, you might think. One would expect those with a higher potential to do better. But the thing is, the score was completely made up and didn’t relate to any ability whatsoever. It was purely the instructors’ beliefs and attitudes towards the soldiers (from their awareness of this supposed command potential) which caused the over- or under-achievement.