The telltale signs are:
Not bothering to look up the connect the dot scriptures during talks anymore.
Still looking up the scriptures but continuing to read and compare the surrounding verses even when the speaker has already moved on.
Elbowing of ones spouse when scriptures are found that contradict what the speaker just said.
Slouching in ones seat and not having ones own magazine during the watchtower study or caring if anyone notices.
Barely concealed eye rolling when certain topics are covered or ridiculous comments are made.
Not singing along with the kingdom melodies or holding back of ones snickers when certain lyrics are encountered.
Looking around during the prayer and seeing all the others that are doing the same.
Not saying Amen anymore.
Vagueness in the form of shoulder shrugging and or a nailed on sickly smile when someone asks " Wasn't that the best Watchtower/assembly/talk-ever??"
Appreciating the individuals one is associating with yet experiencing a certain disconnectedness that occurs when one has has moved on mentally.This disconnectedness is often discernible in ones body language.