The Pygmalion effect is complete rubbish. If you look into it, you see that the original study was p-hacked garbage which relied on impossible gains like indivi

The Pygmalion effect is complete rubbish. If you look into it, you see that the original study was p-hacked garbage which relied on impossible gains like individual students gaining literally hundreds of IQ points (yes, really, they reported this with a straight face and built an entire literature on it, which immediately showed massive decline effects so now the meta-analyses argue over whether the actual effect, which is now like 100x smaller than originally claimed, is distinguishable from 0 or systematic biases). Links: https://www.gwern.net/Replication#pygmalion-effect https://www.gwern.net/Replication#pygmalion-effect My opinionated summary of Rosenthal's oeuvre: https://www.goodreads.com/review/show/1798638457 https://www.goodreads.com/review/show/1798638457 We see the same thing for growth mindset, BTW, if you compare the original studies which made it famous with the most recent rigorous large-scale studies (and then extrapolate out the usual decline effect in long-term followups).