Mel Robbin's five second rule
Mel Robbins is a motivational speaker who recently published a book (summary, TEDx talk, description) dealing with a simple intervention for individuals who would like to start on certain tasks, but have a hard time to do so, challenged by phenomena like shifting priorities and hyperbolic discounting. The individuals count down from five to one, which supposedly will commit them to the task, breaking the activation barrier to start the task by preventing them from overthinking potential fears, building momentum in the face of primal urges, and developing a cue for habits.
Thoughts on potential challenges
From personal/anecdotal experience, it seems like the effectiveness of the technique depends on what percentage of time the task had been actually commenced after the countdown before (i.e., what is the individualized success rate of the technique). The mind may feel afraid of counting down in the first place, knowing that it will jeopardize the effectiveness in the future if one potentially does not subsequently start the task after the countdown. Therefore one could be conditioned to shift the fear to the countdown rather than the activity itself.
The five second rule may be viewed as an act of momentary suppression (fear, laziness etc.). Wegner's white bears show that people have a hard time suppressing thoughts. While the thought may generalize to some emotions (fear, laziness etc.) and while many mindfulness experiments will likely show a long-term benefit for acknowledging - not ignoring - emotions, what is addressed here is the thrust needed to overcome the initial negative feelings only.
A note on the question asked
I was unable to find a works cited section in the redacted advertised versions of the book. I also tried to find papers citing her intervention, but I was unable to do so (perhaps since it was published this year, 2017). Nevertheless, it seems likely that someone has investigated the effectiveness of similar interventions, since the notion of
don't think about it, just do it, since you'll never feel like it anyway
appears quite frequently in media and self-help forums. There may not be any direct experimental results out there (yet). However, I'm interested in existing (indirect and tangential) work that shows that the method may have high effectiveness in practice.
Robbins, M. (2017). The 5 Second Rule: Transform Your Life, Work, and Confidence with Everyday Courage. Simon and Schuster.
Inzlicht, M., & Schmeichel, B. J. (2016). Beyond limited resources: Self-control failure as the product of shifting priorities. The handbook of self-regulation.
Wegner, D. M. (1989). White bears and other unwanted thoughts: Suppression, obsession, and the psychology of mental control. Penguin Press.