What is “Yeridas Hadoros”? The doctrine that the “world is running down”, Jewishly speaking (literally, “the generations’ decline”). But the awareness of Yeridas Hadoros itself causes this to be the case, more than would otherwise be the case.
Here’s Wikipedia on the “Golem Effect“:
The Golem effect is a psychological phenomenon in which lower expectations placed upon individuals either by supervisors or the individual themselves lead to poorer performance by the individual. This effect is mostly seen and studied in educational and organizational environments. It is a form of self-fulfilling prophecy.
In reality, YH is just a copout for not observing the Torah too well (as though many previous generations couldn’t have made the same excuse!).
Instead, we must do all we can, as though YH were untrue, and, endless lectures to the contrary notwithstanding, deemphasize the point.
For the rest of Wikipedia on this, see here.