Nathaniel Branden’s 1969 book The Psychology of Self-Esteem paved the way for the overpraising which characterises both contemporary education and parenting:
…the belief that one must do whatever he can to achieve positive self-esteem has become a movement with broad societal effects. Anything potentially damaging to kids’ self-esteem was axed. Competitions were frowned upon. Soccer coaches stopped counting goals and handed out trophies to everyone. Teachers threw out their red pencils. Criticism was replaced with ubiquitous, even undeserved, praise.
This 2007 article in the New York Magazine reports on new research that dismantles the culture of overpraising. Praise itself is not bad: in a nutshell, praising someone for their hard work is good, but praising them for intelligence is not.