Jim Jones used "the ends justify the means" to pull his followers into highly immoral acts. How can this happen with people who joined his Temple in the pursuit of moral goals? How does someone come to accept such a twisted philosphy?
Through the magic of "investment."
Investment is a deeply embedded coping strategy that evolved to keep humans on track. The man or woman who came up with the wheel probably reached a point where their efforts did not seem to be paying off. Without the concept of investment, they would have given up. It keeps marriages together, gets parents past the "terrible twos" stage with their children, and allows old people to have a cranky license. But like all deeply embedded coping strategies, it can be misused.
Jones had carefully orchestrated receptions for new Temple prospects. They would be shown the glories of membership, tailored to their individual motivations. Idealists would have the lure of social progress. The lonely would have instant family and friends. The insecure would have the promise of being cared for by the Temple. And all would be a part of a bigger, greater, something.
Once a prospect came to enjoy these goals, the first request would be made. A tiny one. A tithe could be donated to the poor and sick. A few hours of unpaid labor in the service of the Temple. Taking a newcomer under their wing. An investment in a system that gives so much.
Then, a little more. Can't the tithe be higher, can't they work a little longer for this big new project, can't they bring some friends and family to Temple next time?
By the time the request reaches a moral tipping point, the outlook has changed. The subject has invested so much that the benefits of Temple membership has become greater than the drawbacks of what they are being asked to do. It's just passing on information from their job, or convincing a possible defector to come back in the fold.
And so, step by step, inch by inch, people find themselves sinking deeper and deeper into moral quicksand. But it doesn't feel like quicksand. It feels warm, embracing, loving. The outside world recedes in importance. They don't need approval and reinforcement from the outside world. They have more and better in the Temple world, where everyone else is approving and reinforcing what they are doing. Where they have invested so much.
So when the big request comes, something so big and uncomfortable to contemplate that they want to pull back, they have gone past their feet into the quicksand, past the point where one big step could get them out. They've gone past their knees, where it would require the effort of their arms and a strong rope. They are up to their hips in it, and to struggle out would require their entire body. It would require relinquishing their entire Temple life.
Or, instead, all they have to do is a mental adjustment; to look at what they are asked to do as an unpleasant task, to be sure, but one they can justify in terms of survival. To keep their life.
And self-preservation is the most deeply embedded coping strategy of them all.