[superobserver]

Clearly not accurate. For one thing, there are many kinds of meditation, so the assessment that meditation (as a whole) is demotivating is overgeneralizing. Secondly, as further revealed by the study itself, motivation isn't a factor for successful task completion, so there may be something about self-attributed motivation that is superfluous to task completion (i.e., meditators become disabused of that and merely handle the task at hand).