I'm glad you posted this.
I've had a lot of experiences of contact highs. Now, on one hand, it is to be expected that if you're in a good mood, others around you will have that mood rub off on them. That's how humans work... we are affected by one anothers' mental and emotional states. And for the record, AMT is one of the best substances there is at providing a contact high to others.
However, I have had some pretty weird contact high experiences. Before we were married, I would trip around my wife pretty often without her knowing, as she has never tripped and is incapable of treating me as she normally would if she knows I'm tripping. On many occasions, especially on 2C-I and DOC, she would start to report the same symptoms I was having, even including visual patterning. On other occasions, I was tripping on something when she and a good friend of ours were hanging out, usually when we'd be spending the day biking at a great outdoor location nearby. I remember one time in particular, I was on a low dose of 2C-T-7 and mushrooms and the world was looking so beautiful. We stopped to stare at the sky and the clouds for a bit. The clouds for me were swirling around in that amazing psychedelic way, and my friend who was with us suddenly commented about how the clouds were breathing and he felt like he was on acid (acid is the only psychedelic he's done). I never told them I was tripping. Another time, when that same friend and I were at a party, before I knew him well at all, I was on 2C-I. I actually wrote a report about this experience which is on Erowid... you may have read it before. But the entire party seemed to have gained my ability to feel the social vibes to an enhanced degree, and throughout the night I heard many people express confusion at what was going on. But the most telling was when I overheard this friend of mine say to his girlfriend "Man, who slipped the acid in the drinks?"
I have all kinds of experiences with contact highs. I would say it's just emulation of emotional state, except for the fact that I've repeatedly had friends report visuals out of the blue without knowing I was tripping. Actually, I still think it's emulation of mental state, just that there is more possible with this emulation than people might tend to think.