What are the intended and unintended consequences of increased lengths of incarceration?

I believe intended actions are to prevent further criminal action from occurring, disciplining inmates and offering salvation to those who committed crimes by mandatorily serving time. Unintended consequences like the environment of having to be around so many inmates is increased hostility, mental instability and isolation contributing to inmates psychological deterioration. Simply put, intended; be a good boy, don't mess up and maybe one day you'll get out. // Not intended; being a bad boy because you've been given a life sentence and see no reason not to throw your life away because you're not getting out anyways.

Explanation:

constructive criticism

all i have to say is that people are truly ignorant and don't have anything better to do with their lives.