I used to work on a government project where we were tasked with building lie detectors based off the concepts of blink (micro expressions) (and really Paul Ekman [1], where the concepts in blink came from)

After a few years at it, I came away thinking the whole thing was bullshit. Unfortunately, countless tax dollars were wasted.

[1] https://www.paulekman.com/blog/signs-of-lying/