OK - so after conversations with several people, all of whom I've been
talking with separately, here are some hypotheses that seem to be taking
shape:
1) "The difficulty of completing a task is a function of the number of steps
involved in the task and the time it takes to perform each step."
2) "The time it takes to perform each step in a task is a function of the
relative complexity of the step and a person's willingness and/or ability to
understand and complete the step."
3) "The more difficult a task, the less likely it is to be completed."
I think this is