Why do people become Religious Fundamentalists?

Recently, I've been thinking about why people might go from relatively uncommitted religious believers or atheists to hardline religious fundamentalists. Here are a few ideas:

• Some sort of personal revelation could make someone a more devout religious believer.
• People who come to fundmentalism may be uncertain about their lives and accepting some sort of certainty may make them come to fundamentalism, becuase it makes them feel that everything is already explained and they don't need to worry so much about their personal lives.
• Some people who come to fundamentalist religion may have some sort of addiction that fundamentalism, essentially, replaces.
• Some people are incredibly reckless and struggle with handling resposibility, and cannot deal with life without a strong set of rules which fundamentalism provides.

Obviously, these ideas don't represent all fundamentalists. Most fundamentalists are so because of upbringing. This list probably doesn't represent all people who came to fundamentalism late in life, either, just some ideas as to why people might.

The Authoritarians

I stumbled across this online book entitled The Authoritarians the other day. I read it, and found to be a very interesting read. Here's where to find it if you haven't already seen it. It discusses some very interested research on the group known as Right Wing Authoritarians(high RWAs) and why they think the way that they do. High RWAs are likely to be submissive to traditional authority(eg government, churches), and want everyone to live in the same way that they do. These people are politically conservative in the United States.
These people are very likely to have poor reasoning faculties, discard reasoning if they agree with the conclusion, discard ulterior motive if they agree with the conclusion, have double standards, be hypocritical, hold contradictory beliefs without realising it, be self-righteous, blame the victim rather than authority, be aggressive to out groups especially if an authority they trust says they should be eliminated, and be more fearful than average.
High RWAs are very likely to be religious fundamentalists so if you're interested in insight into the fundamentalist mindset this is definitely worth a look.

It also contains information on the Social Dominance Scale, which defines how much power people want to have(often just for the sake of power). Although there is often not much crossover between high RWAs and high social dominance(as most high RWAs want to be led, not lead) there is a crossover of about 5-10%. People high on the social dominance scale manipulate people, have very few scruples, will break the law if they think they can get away with it, lack empathy and are prejudiced and bigoted.
People who score highly on both scales are the most bigoted of all and they actually believe their own rhetoric. A lot of these people appear to be in the Republican party.

That's an incredibly brief summary of the kinds of things discussed in The Authoritarians. Studies on these people are discussed in detail within, as well as more examples and explanations of their behaviour. If it sounds like something you'd be interested in, take a look!