I've been meaning to put this up here for a while, so here it goes.
This photo is called the "Cusp Catastrophe Model" (for more on cusp catastrophe go here Physchologist Leslie L. Downing has used this model to show how people tend to behave when either accepting new beliefs: (His work on this Subject can be found in the book "War in Heaven, Heaven on Earth")
It may appear to be confusing, but I think that once you take a closer look things become quite apparent. Let me define each parameter:
Commitment forces (control factor 1) - things that push a person to continue to commit to a certain belief. In the case of the Watchtower this would be things like going out in field service, giving talks, going to meetings, studying your watchtower, fear of loosing family)
Conversion forces (control factor 2) - thing that push a person towards accepting a new belief. This could be likened a Catholic person letting a JW have a 'Bible Study' with them. The JW is a conversion force, something that pushes the person from Belief I to Belief II. Belief I & Belief II - Pretty self explanatory. Remember that once a person converts from Belief I to Belief II they are essentially back at the top of the model again, but with a new belief system.
Behaviorial plane (aka B1 - B2) - show the process that leads a person to converstion and commitment to a new belief. In some cases it is really slow, in other cases there can be a very drastic change in belief. The purpose of the cusp model is to illustrate the differences between the two.
Explanation
Let's say you are an American Catholic. Most American Catholics that I know are pretty lax about their religion, so we will pretend you are one of them. In terms of the cusp model this means are at Belief I, but with low commitment (B1, the top right corner). You aren't that involved and do not view the religion at the center of your life.
But now this is about to change. One day a JW comes to your door and offers you a Bible Study, and you take offer. The Bible study you have weekly becomes a conversion force in your life. That person comes back each week, and slowly pushes you towards becoming a JW. At the very least most studies JWs have with people last at least 6 months to a year, but some last for many years (even decades!). Slowly the JW will convert you, one opinion at a time to his set of beliefs (B2). This is a gradual change, nobody becomes a Jehovah's Witness in a few weeks!. Once you come to Watchtower meetings you have now let another conversion force into your life. How about field service? Nothing helps commit a person to a belief system better than making them sell it to others. The point is that as time progresses the conversion forces become strong and stronger. That free home Bible study just turned into 3 meetings a week, love bombing, and much more. Eventually the person gives into these forces and commits to the group.
Fast forward ten years later (in my own personal case it was 7). Now that a person has gone through the gradual change of conversion he finds himself back at the top of the cusp model. Difference is now that casual Catholic believer has turned into a dedicated and highly committed member of the JWs. This means that we now find them at the top of the cusp (B1, were belief 1 is now their JW beliefs) but on the left hand side of the model.
This is were it gets really interesting. Notice that when then lax Catholic left his Catholicism, it was a gradual change that happened over a long period of time. This changes now because our example person is now a strongly committed JW. He goes out in field service, fears he will die in Armageddon if he doesn't preach enough, goes to three meetings a week, studies his watchtower (because god will hate him if he doesn't), ect. The point is that being a witness means letting the Watchtower be a 'commitment force' in your life. To a Catholic that dosn't take his religious leaders very seriously the Pope, priest, bishop ect. isn't a strong commitment force in his life. To a JW though, the Elders, Circuit Overseers, Ect are a very strong force.
Now lets look at what happens when people who are highly committed to the JWs begin to doubt their faith. They will now feel a number of 'conversion forces' against them. This could be doubting that Gods spirit is with your local Elders, seeing coverups and wrongdoing in the congregation, reading 'apostate literature', ect (usually it is a combination of these things).
Notice the difference between somebody who leaves a religion that requires high commitment and one that requires low commitment. Compared to low commitment religion, people in high commitment religions will begin to have a gradual change towards accepting a new belief but then reach a point were the change in their opinion is drastic (notice the stepwise).
Because their belief structure is so demanding upon them, once they begin to see even little things that show their religion to be wrong, it may be enough to collapse their entire view of the faith. This is especially true in the Watchtower were the is absolutely no room for personal opinion in regards to beliefs. This mean that when somebody finds out about something that breaks the mold (U.N. Scandal, 607 information, ect.) It is more than likely going to get them questions many other aspects of the religion as well. The cracks spread quickly in this regard.
Essentially, the more you demand the more likely it is people will eventually come to resist. I believe this explains why so many people leave the Jehovahs Witnesses (50% and higher).
This model also helps explain the behaviors of 'fringe believers' as well. I like to use my father in law as an example. He has never actually become baptized by the JWs, but is an unbaptized publisher. He used to have a bible study, but gave up on it. He goes to meetings, but doesn't pay much attention. Mostly he just goes along with what his JW wife is doing. He does field service, but hates it. On the chart he can be spotted somewhere in the upper right corner, a little down the cusp. While he has 'converted' to a number of things, it has not been complete. Additionally, conversion forces are not strong in his case, meaning he gose along with it all but is no were near the place an active believing member is. This helped me and my wife see that we could never appeal to him as a JW. He dosen't know what it is like to be a JW and is confused when we explain it. Even though he goes along with the JW lifestyle, he still is very much out of touch with it.
I've always wanted to share this with JWD, hope you enjoyed!