We don't need another "study" to determine that solitary confinement does psychological damage to human beings. You have to make up your mind what you want to accomplish by locking people away. Do you want behavior modification or do you want punishment? If you actually believe that putting a person in prison will change their behavior, then you have to do more than you do in the current system. If all you want is your pound of flesh, then any discussions are superfluous because you don't actually give a crap about how ANYTHING affects or effects future behaviors.