Is It Imperceptible That Contractions of the Facial Muscles Cause Tears?

Tears are a true adaptive trait that serve their own functions and function independently from just the contractions of the facial muscles. I've seen this invoked as an explanation for why sometimes your eyes get teary when you yawn. Most researchers who focus on this area really do think that this is not a plausible explanation. It seems like the tears being produced by the lachrymal glands during an emotional episode, something that exceeds this kind of tearing.