An example on how this is NOT employed, see the recent cold fusion article on slashdot. Most of the psot were "gushing" over rossi's stuff. But a bit of critical thinking and information digging would have revealed a lot of red lights to this story.
In my experience with your average person, and with student I taught in university, critical thinking is a rare skill (please do not confuse it with cynism). We are all taught in our young age to just "learn and shut up" and get told that we'll learn why the world work so "later". So people lose their critical thinking skills and just do what they are told. This is why all religion is taught to children by the way. They do not have this critical thinking skills yet, or it can easily be killed off by parental authority. If religion were really true, then they would not need to catch children young, rather than wait that they are adult for such decision. Sure they'll shield it in a shimmer of saving them while they are young, but the effect in the end is the same.
The bottom line is that this is something which should be nurtured, taught, and shown in evry small school. The rote learning we got instead is toxic. It etaches you to learn without criticizing or thinking.