In considering the evolution of the human brain a critical point comes when the quality of cultural information is such that it has more survival value than working things out from first principals. AT this point it pays to learn by following the best teacher (initially the parents) to maximise the speed and efficiency of learning the culture. This process will enable more and hopefully better culture to develop - so evolution will strengthen the tendency to follow the most charismatic teacher . This may have been fine when we were hunter gatherers in the woods but can go wrong in modern times, where a charismatic leader may have the power to influence large numbers of people for god or ill.
An article "The Limits of Critical Things" has just appeared in the online magazine "Skeptic" which examines what happens in practice. It is by Jamy Ian Swiss, a professional magician. He writes:
My experience with deception has proven to me that the human brain is evolutionarily programmed to be readily manipulated, whether by the likes of itinerant conjurors like myself and James Randi or by virulent megalomaniacs like Marshall Herff Applewhite. The human tendency to organize information even where no useful information exists appears to be hardwired into our brains. It was there for the first aboriginal rain dance, and it’s here today for the most contemporary forms of magical thinking. That tendency to organize, to look ahead and be creative and surmise from thin evidence is a distinctly human trait, as responsible for the greatness of the human condition as it is for its follies and failings. Our human “big brain” is an accident of evolution that may well be our salvation or undoing as a species, with its abilities to invent, create, explore and imagine, or to become addicted, depressed, or believe incredibly dangerous ideas in the face of all evidence to the contrary.
When we see the apparently placid willingness of the [Heaven's Gate] cult members to fulfill their grisly task of self-destruction, it is difficult to view them as victims. Considering the patently ludicrous ideas the cult based its belief system on, it’s tempting to write the followers off as cranks who were victims only of their own willful stupidity. But the phenomenon of cultism is characterized by distinctly manipulative practices of recruitment and maintenance that must be considered independently of the particular belief system they happen to be promoting. Toxicly effective cult leaders like Herff Applewhite will always produce followers who swear to their willing allegiance and free choice just as the observer of a magic trick will swear he never looked away the whole time the magician’s spoon was magically bending. Both victims are certain they had all the information necessary to make a capable judgment.