When we are conscious we look out at the world through a large hole in our heads between our noses and our foreheads, or so it seems. It is possible to pin-point the exact place inside our heads which is the ‘here’ to which everything is referenced. That spot is about 4-5 centimeters behind the bridge of the nose. Not only sight but hearing, touch and the feelings from inside our bodies are some distance in some direction from that spot. As far as we are concerned, we carry the center of the universe around in our heads.
Both our sensory system and our motor system use this particular three dimensional arrangement centered on that particular spot and so locations are the same for both processes. How, why and where in the brain is this first person, ego-centric space produced? Bjorn Merker has a paper in a special topic issue of Frontiers of Psychology, Consciousness and Action Control (here). The paper is entitled “The efference cascade, consciousness and its self: naturalizing the first person pivot of action control”. He believes evidence points to the roof of the mid-brain, the superior colliculus.
If we consider the center of our space, then attention is like a light or arrow pointing from the center to a particular location in that space and what is in it. That means that we are oriented in that direction. “The canonical form of this re-orienting is the swift and seamlessly integrated joint action of eyes, ears (in many animals), head, and postural adjustments that make up what its pioneering students called the orienting reflex.”
This orientation has to occur before any action directed at the target or any examination of the point of interest by our senses. First the orientation and then the focus of attention. But how does the brain decide which possible focus of attention is the one to orient towards. “The superior colliculus provides a comprehensive mutual interface for brain systems carrying information relevant to defining the location of high priority targets for immediate re-orienting of receptor surfaces, there to settle their several bids for such a priority location by mutual competition and synergy, resulting in a single momentarily prevailing priority location subject to immediate implementation by deflecting behavioral or attentional orientation to that location. The key collicular function, according to this conception, is the selection, on a background of current state and motive variables, of a single target location for orienting in the face of concurrent alternative bids. Selection of the spatial target for the next orienting movement is not a matter of sensory locations alone, but requires access to situational, motivational, state, and context information determining behavioral priorities. It combines, in other words, bottom-up “salience” with top-down “relevance.””
We are provided with the illusion that we sit behind our eyes and experience the world from there and from there we plan and direct our actions. A lot of work and geometry that we are unaware of goes into this illusion. It allows us to integrate what we sense with what we do, quickly and accurately.