Seems like it's this 2020 study https://www.nber.org/system/files/working_papers/w26719/w267... (also found this blog https://news.uchicago.edu/story/how-your-speech-could-impact...)
It seems odd they've kicked this up years later, but the recency is apparently due to some survey data https://www.wsbtv.com/news/local/study-claims-having-an-acce...