Empath

I've been thinking about this for a while. Is this unique to me or universal or shared by only a few?
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When I listen to a piece of music, look at a piece of art, enjoy a sunset or lovely vista -- if I am alone, I will have some particular emotion that I know is mine. But if there is another person with me, I will hear or see with their ears and eyes; the emotions are mixed up with theirs.

Example -- a friend played a particular song on a CD that he really liked and asked my opinion; yes, I liked it very much. Later I listened to the CD alone and found that song to be merely OK and another song was much more to my taste.

Another example -- I live on a fairly busy street and, when the wind is right, also within hearing distance of two highways. Alone in my backyard or hot tub, I am rarely conscious of street or traffic sounds. With another person soaking next to me, I hear the traffic much more clearly, even though we may be chatting.

Third example -- My planned college major was English Literature but after an introductory Art History class where I got the highest A in the class, I changed. Looking back, I think I know how I got almost consistent A's in Art History: most lectures and all exams contained slides projected on a screen. The teacher was also looking at the slides and I could pick up their feelings about the piece. The only B in one of my major courses was from a class where the teacher was new and not particularly interested in the subject, just teaching it because no one else was available. So, I could not pick up any particular cohesive emotion.

The reason, I believe, that this ability didn't work for me in the English Lit classes was because most small group discussions were led by graduate assistants who did not project strong emotions about the subject; they were just putting in time to earn their subsidies so they could write their theses.
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Had I taken the introduction to music appreciation course that semester, instead of the introduction to art history, would I have become a music major? Probably not. My empathic ability seems to be more strongly visual than aural.
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My question to you: is this ability unique to me or universal or shared by only a few? It is NOT telepathy; I cannot hear or know my companion's thoughts, only sense their emotive reactions to a particular sight or sound.