Is there any direct or indirect empirical support for the effectiveness of Mel Robbins' five second rule? 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.  

Suppression

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.

References

Robbins, M. (2017). The 5 Second Rule: Transform Your Life, Work, and Confidence with Everyday Courage. Simon and Schuster.  

Inzlicht, M., &amp; 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.
I'm having a difficult time finding anything on suppression aside from various bits on the white bears experiment you noted. Of particular note is this study, I suppress, therefore I smoke detailing how suppression can help with immediate control. But, when they stopped suppressing a large rebound effect occurred. This would indicate that the five-second rule, at least for continued behavior change, might have some drawbacks.

It seems like her evidence for the five-second rule is based on the culmination of other individuals work. So in the absence of evidence to support, I'll work through her claims. 

She takes psychological concepts and describes how the five-second rule either enhances or overcomes them. Mel Robbins cites five principles of how the five-second rule overcomes the 'tricks your brain plays on you', in this video. 


Locus of Control &amp; A Bias toward Action
Behavioral Flexibility 
Do good, Be good
The Golden Rule of Habits 
Activation Energy 


Locus of Control is the extent to which you believe you have control over your life. A concept rather than evidence. Robbins argues that the five-second rule will help promote your locus of control by giving you a bias toward action, that is doing over thinking. Locus of control is assumed to be related to self-efficacy, the belief in your own abilities. 

Behavioral Flexibility Robbins asserts that only recently scientists have discovered our brains continue to grow after age 25. The research I believe she's referring to is about maturity and adulthood. I'm not sure how this relates but apparently it's good news because we can use the five-second rule even after the age of 25.

Do good, Be good Is based on Timothy Wilson's cognitive behavioral therapy work around 'narrating your story'. From what I understand, his work focuses on writing or talking with yourself to better understand your thoughts. He mentions briefly that one way to change your narrative is to act how you want then narrate from there. I have not found any evidence this is a 'proven technique' like Robbins states.

The Golden Rule of Habits is the concept that the only way you can break a habit is by replacing it. Starting with the cue. Robbins asserts that the five-second rule becomes a cue and by extension, gets you in the habit of action. There's extensive research on habits that might support this and a bevy of similar techniques. 

Activation Energy is the starting point for 'flow' which is based in scientific research. You need something to trigger that minimal exertion to get start on your task. Robbins asserts that the five-second rule can be used as your activation energy. 

The final and probably biggest claim is that counting back from five activates the prefrontal cortex which can override what looks to be the amygdala. I can't find substantive evidence for this statement either way.