The article linked is not the one of the actual study. Here is the actual study: https://s18798.pcdn.co/motivationlab/wp-content/uploads/site...
A cursory look shows the study talks about identity projection and actions (law students given extra material and asked to watch it, are less likely to watch it if they have told their observer they are going to watch it). However the difference is 1 minute of less watching and could be attributed to other factors.
Additionally, the same author has published research 5 years later (https://s18798.pcdn.co/motivationlab/wp-content/uploads/site...) that explains goal projection in public places is helpful as " is part of our everyday life and is fostered by high-goal commitment, perceiving others as similar, and ongoing goal striving.". So it is one thing to say you are going to be better at something by own self-study, but another when you are actually pursuing something and need help to achieve it. Announcing something allows you to connect with others sharing the same goal to get help or community, and shows you continue to be committed.
Feel free to read the studies and see if you can draw other conclusions, but this is not as black and white as the article claims.
Additionally, the same author has published research 5 years later (https://s18798.pcdn.co/motivationlab/wp-content/uploads/site...) that explains goal projection in public places is helpful as " is part of our everyday life and is fostered by high-goal commitment, perceiving others as similar, and ongoing goal striving.". So it is one thing to say you are going to be better at something by own self-study, but another when you are actually pursuing something and need help to achieve it. Announcing something allows you to connect with others sharing the same goal to get help or community, and shows you continue to be committed.
Feel free to read the studies and see if you can draw other conclusions, but this is not as black and white as the article claims.