The long and short of it is that if you tell other people about your intention to accomplish something in advance, you get to pat yourself on the back without actually achieving anything. This apparently reduces your motivation to follow up on the commitment because you've already reaped the reward.
> "This apparently reduces your motivation to follow up on the commitment because you've already reaped the reward."
That's not universally true. Also, having skimmed the paper, that's not quite what the authors state.
To quote the paper "...participants felt closer to the identity goal of becoming a jurist when their behavioral intentions were recognized than when those intentions remained private." This says nothing about motivation and in fact motivation (or even actual work) was not at all examined in this study. For all we know, those students did go on to do better or "... read law periodicals regularly" as they said they would.
In fact, there is compelling evidence that the opposite is true: http://www.psych.nyu.edu/gollwitzer/09_Gollwitzer_Sheeran_Se...
The long and short of it is that if you tell other people about your intention to accomplish something in advance, you get to pat yourself on the back without actually achieving anything. This apparently reduces your motivation to follow up on the commitment because you've already reaped the reward.