This seems to be a common characteristic of people as well; we tend to doubt, or even fear, our potential. Marianne Williamson (1992) captures this in the following popular statement:
Our deepest fear is not that we are inadequate. Our deepest fear is that we are powerful beyond measure. It is our light not our darkness that most frightens us. We ask ourselves, who am I to be brilliant, gorgeous, talented and fabulous? Actually, who are you not to be?
In other words, just like Jumbo, Jr. was capable of great things, but needed some kind of artificial encouragement, it may be that some of us need a gentle psychological push towards greatness as well. Click here for another example from Corsini and Wedding (2007, see p. 4).
In both examples, the subjects' abilities were unchanged. Jumbo, Jr. was always capable of flying, just as the inmate was always intelligent. The difference happened when they believed in their abilities.
I find that, in many ways, the LDS church (and many religions for that matter) similarly is the proverbial feather in the process of helping individuals reach their potential. If that were where it ended, I do not believe I would have much about which to criticize the Church. However, at the same time it gives people that extra boost towards appreciating their potential, I find that the Church too often creates dependency, essentially insisting that although we can achieve great things through the Church, it is only through the Church that these things are possible. For example, the LDS church would have the world believe that without it, the following are (at least nearly) impossible:
In reality, each of these can be found outside of the Church's influence. I feel that rather than telling us all that we have inherent divine potential, but without the Church we are nothing, perhaps we have great potential no matter what the Church tells us. With all of the feathers they try to pass off as magic (e. g., priesthood, inspired leaders, the Holy Ghost, etc.) maybe the real power lies within us.
Williamson, M. (1992). A Return to Love: Reflections on the Principles of a Course in Miracles. New York: Harper Collins