Thanks everyone for the responses. I suppose I am trying to understand the difference between:
#1 – Watching someone’s eyes (without locking eyes) – just to see where there gaze is directed
#2 – Watching someone’s eyes (without locking eyes) – simply because you don't know where else to look (sort of like not knowing where to put your arms)
#3 – Watching someone’s eyes and then momentarily locking eyes, and then immediately looking away
#4 – Actually locking eyes, maintaining bi-directional eye lock, and continuing discussion AND THEN looking away after a certain period of time
While I haven’t really put a lot of thought into this topic, I assume that if you don’t achieve #4 (for some period of time), there is a “marked impairments in the use of multiple nonverbal behaviors such as eye-to-eye gaze”. If so, what is that period of time? Is 1 second enough? More? And, whatever period of time it is, do you have to be able to lock eyes and be able to converse simultaneously (which sounds really hard, to me)?
Then, if someone does #1 or #2 or #3 a lot, is that a sign of Social Anxiety or something similar?
As a note, I have tried to observe people (strangers) in conversation, trying to ascertain if they were locking eyes and for how long. But, I felt awkward when they looked at me. So, I stopped. LOL.