Has this phenomenon been studied before?

While not directly the same thing, it has been known for some time now that depression and elation affect estimates of inputs. People who are depressed will focus on negative outcomes, etc., etc.. This has all the earmarks of being a positive feedback loop. The "concreteness training" seems to have consisted of indoctrinating the trainees with the knowledge/belief that they could have affected the outcomes of negative events -- disrupting the cycle as it were.

So while yes this is interesting, it also isn't very surprising.