Thanks for your answer but unless you've converted away from your physicalist mentality, you are not talking about what I was calling super-physical vibrations. You are talking about brain reaction. I'm actually talking about vibrations from without entering a person's physical and super-physical (astral, etc.) fields.
I have queried several temple priests, monks etc. with the question: Why do some people feel this and others don't? This came about through observations such as:
-One person showing tears of bhakti, at the same time and place as another walking by apparently totally oblivious
- asking various people about the 'strength' of a particular temple, comparing notes, then getting varying answers
- talking with different people about my experiences in different temples. For example, one person I know told me he felt tremendous vibration at Chidambaram, yet nothing at Tanjore, yet for me, the opposite was true... not nothing at Chidambaram but far less than at Tanjore.
So in summary, the priests and swamis suggested that the whole thing has several factors at play:
1) the general openness of the devotee ... both emotionally, and mystically ... some people expect nothing so get nothing, while others are just far more sensitive to vibration
2) the astrology of the day .. in this case it was for a day to day situation, and 90% would agree that one day felt stronger than another
3) the personal relationship of the person top that particular deity, or even that particular murthi... we have two murthis here, (Ganesha) the original one and a bigger one installed at the kumbahbhishekam, many people, especially the elders, because of the relationship that has been established, feel more from the smaller one
As for a particular deity, but not murthy, its just stands to reason a Saivite would feel more from Siva
4) the devotion established at a particular temple, or even the devotion on a particular day from others, the group effect
So it's complicated. I think this energy is undeniable though, yet of course if you can't feel it, you can't feel it.
On many occasions in my life I've had non-Hindus notice it, some more than others. A colleague friend who was curious about my faith one night came to a puja. The very first question out of his mouth after was: "______, does your religion believe in some sort of energy?"
Although I understand why some people might not get it, in a way I feel sorry for them, because for me its like winning the lottery. Meditation is so much easier at or after temple worship, insights are gained there, it's really a house of mysticism.
There are also many barriers to going. Things like fear of crowds, fear of unfamiliarity, fear of being the only stranger, a past conditioning to the evils of idol worship, even repressed but subconscious racism. Another factor is the intellectual conviction that temples are for the superstitious. It's tough to overcome all that.