Because mastery is such a powerful motivator, even small signs of progress can have a large effect in motivating people move forward to the next step in a task. At Linked In, they encourage you to finish filling in information on your profile by showing you how much information you have already answered.

https://www.blog.theteamw.com/2011/03/16/100-things-you-should-you-know-about-people-82-people-are-motivated-by-progress-and-mastery/