I came to the same conclusion as you. When a person believes they won’t be heard when they speak, in most cases, they will speak fluently 100% of the time. I don’t have a physical issue like some people who have jaw problems that cause stuttering; in my case, it’s purely psychological. What I think we can take away from this conclusion is that the fear of stuttering in front of others, and then being judged for it, actually causes the stuttering. I’m not an expert in the field, but accepting stuttering and getting used to hearing ourselves stutter can indeed help ease the problem. The more importance we give to stuttering, the stronger it becomes.