What are effective methods to overcome the initial psychological resistance towards an unpleasant task?
I don't know of evaluations of those types of techniques. To broaden your query slightly, there is strong evidence from social psychology that increasing helpful behaviors and decreasing unhelpful behaviors is more about context than willpower (e.g., see how Nisbett &amp; Ross talk about the power of the situation for behavior: http://faculty.babson.edu/krollag/org_site/soc_psych/ross_pers_sit.html). So if a person were seeking to initiate difficult behaviors, I would first modify the context rather than use the tools mentioned. For example, if a person had trouble doing a work task and was using stackexchange as a distraction, they could disable their internet for a period.