Why can we feel people looking at us?

There are two kinds of ecstasy: the kind that will produce sensations from the peripherals moving inward; then there is the other type of ecstasy, that experience of pleasure, pain, instability, beauty, death, life, all at once, this type of ecstasy starts from within and moves outward.
After I spill my thoughts out, I stand a bit more erect, shake my head side to side, sit with myself. I feel the tendons and muscles along my arms that connect up to my shoulders relax. I am able to let my fingers, that are normally pulled up slightly when my hands are at my side due to the tightness in these tendons, relax downward. Not a forced relaxation, not a conscious one either, but that I can just sit a little easier, sit back on it, be in my body, slight smirk on my face. And off into the ether it goes.
Its funny how much I am doing some form of research, in my free time. I get hooked on an idea, trying to parse out evidence in my head while I am at a bar with friends, or doing mind numbing work, where my thoughts twirl and leave my head. They leave and they ponder. They sit under a peaceful tree and partake in their own form of exercise, namely to try and find serenity. It’s not a desperate effort, but a slow and steady one. I can rush things in life quite a bit but I never feel that my thoughts are rushing that search.
Recently, I have become fixated on the notion of why you can feel people looking at you even though you can not see them. Every person has felt this, whether someone is trying to make out what your shirt is, or legitimately starting at you; there are times in life where you can feel someone looking at you without any eye contact or peripheral vision of your own coming into play. It started to dawn upon me that all of our senses involve some sort of interaction with a physical phenomenon, except this one. Sight involves light waves getting refracted and hitting the back of your retina, exciting certain molecules in your retinal cells, sending an electrical message to your brain. Sound involves waves of sound passing through air, where the air molecules vibrate at a particular frequency, causing a minor change in pressure; this is the felt by our very sensitive outer ear. Smell involves particular molecules in the air binding to certain receptor proteins in our nose and sending an electrical pulse to the brain. Taste involves the same kind of molecule-receptor interactions that are involved with smell. Touch involves a physical force being exerted on our skin. But being able to feel someone looking at you; when there are no light waves, forces, vibrations of the air, or molecules to bind to receptors, no physical phenomenon by definition, this is interesting. Why can we feel their stare?
As of right now I don’t know any pre-existing way to figure out what is going on here. There is nothing to measure. You can measure how quickly people may feel this, if all of them feel it under certain circumstances, etc. etc. But the deeper cause? I’m not sure we can figure this out right now.
It’s come to my attention that there are many different ways to understand something. You can understand it logically, emotionally; you can understand by experience, acceptance, and a myriad of other ways that may not fall into traditional forms of “understanding.”
So if the direct cause of this phenomenon can not be measured, how can we get an idea of what is going on? The idea of limits comes to mind. Limits are the foundation of all calculus. It is nothing more than looking at where something is going, and seeing what its value is as it gets closer and closer to that point. In calculus, if you want to find the slope of a curve, you take two points on that curve and you can get a slope from that straight line drawn through those points, as the two points get closer and closer together along the curve, that straight line that goes through them becomes a more and more accurate representation of the slope of the curve. You can not measure the slope when the two points along the curve are on top of each other, but you can see the pattern as the two points approach each other, when their distance along the curve approaches zero. This beautiful idea from Newton, can be superimposed on non-mathematical problems. Or at least, I think it can. I am not trying to prove anything to anyone, convince anyone of anything, but letting the stream of consciousness flow, to try and better understand the nature of life, biology, reality. Who cares if I adapt a concept from mathematics and apply it to another problem for my own means? You can join along or not, it’s up to you. No one is going to make you though.
Let’s take the idea of the limit and apply it to the question of why we can feel people looking at us, even though there is no (known) physical phenomenon at work. What might the patterns be leading up to the question? I don’t think any answer is wrong.
For me, after not talking to people for most of my days, doing work, smoking cigarettes, thinking, repeating; I listened to a couple stories on a podcast. One moving story was one of a dad hearing Isn’t She Lovely by Stevie Wonder in a grocery store right after his daughter was born while he was getting his wife some non-hospital food, he dropped to his knees, overfilled with emotion. Literally laying on the ground “clutching an Italian Soda.” The big bad manager ended up coming up to him as an employee thought something was wrong. The man, overfilled with emotion, decided to be honest with the manager and tell him, and when he told him, seconds later, he was “buried in man.” The manager had clutched him as hard as he could and was crying, saying “I had my daughter 3 month ago.” They both felt this very intense, beautiful experience, like it was almost too much, and they both understood one another.
I’m not sure why that story stuck out to me so much, but after being so solitary for the majority of my waking days, feeling that story as it was. He wasn’t telling it with some super raw emotion, near crying type of storytelling, but more of a “this is how it went down and now I am going to share it” kind of storytelling. I was nearly tearing up, I could feel this raw emotion bubbling up inside of me as the storyteller was instilling this feeling in me.
The ability to provoke raw emotion in others with words is something to marvel at. Someone writing something in Africa can instill an immense amount of emotion in someone reading those words on the other side of the world. But the words don’t carry the weight on their own. They offer up a recollection of emotions and thought, trying as best as they can in their choice and combination to evoke the same feeling that is within the writer. This makes me wonder, stuff like this kind of points in the direction of some sort of unified consciousness between people and other living things (although I do believe we have lost touch with tapping into this consciousness). Maybe, perhaps, the ability to feel people looking at us is an existing artifact of a collective consciousness that we have lost track of. I’m spitballing, but how else do you explain those crazy moments when someone you love is hurt or feeling joy, and your day and emotions match theirs. Or you feel like you can see someone who is no longer alive, in someone else’s eyes. This kind of stuff can’t be backed up by science at the moment so it’s a bit hard to say with any authority, but those “that was weird” moments where things seem to feel so damn connected… I don’t think we can ignore those blindly. At least dive in a little for ourselves. Try and see what is perhaps there, or not there, try and see the patterns that we can see right now, and where they are going.