By Dr. Ken Broda-Bahm:
Damned if it isn't true: People who swear are more honest, and perceived as more persuasive. According to a recent Psyblog post, that is indeed what the research shows. The most recent study on the subject (Feldman et al., 2017) looked at both self-reports as well as an analysis of Facebook communications to demonstrate that a greater use of profanity correlates with greater honesty. An earlier study (Scherer & Sagarin, 2006) shows that, in addition to actually being more honest, the person who swears is also viewed that way, with the addition of a 'damn it' at the end of a message increasing perceived intensity and influence. Why would socially disapproved language add influence? Well, according to one of the authors in the 2017 study, Dr. David Stillwell, it has to do with a connection between lower filtering and greater honesty. When someone is letting the bad words slip through, Stillwell writes, "they are not filtering their language so they are probably also not putting their stories about what is going on through similar filters which might turn them into untruths."
So, apparently, it is a matter of authenticity. If you come across as more direct, then you're less likely to be seen as filtering your language or carefully and insincerely picking a position. Now, of course, this research is unlikely to be applied literally by an attorney or a witness in court. Swearing up a blue streak in the courtroom is likely to end up with a My Cousin Vinny-style quick trip to jail for contempt of court. But if we look at the results a little more broadly, it isn't that people like swearing, it is that they like the perception of less- filtered communications. Dropping filters promotes perceived honesty. That, I think, is a broader point that attorneys and witnesses can take into the courtroom: Drop filters by showing that you are, to a small extent at least, stepping out of the formality and expectations of a contrived position. In this post, I will share a few ways you can do that...without swearing.