I have a theory, I think is the relationship between the factors, where a human being and its perception is a conglomeration of processes organized in a specific way, and has many properties, one of them is malleability and all we know of cognitive science.
and the other is the environment.
How accurately the conglomeration of processes, and the mechanisms organized in a human being perceives the environment or everything it sees outside itself is completely dependent on this organization in interaction with the enviornment.
We are bombarded with ideas of what "IS" in this 3D reality, through indoctrination science etc, and this certainly puts a person in a state of presumptive existence about what is possible based on what is acceptable.
This is a mind set, setting the mind to willingly narrow possibilities from a full picture unbiased and complete, to the person wearing off fashion shoes, the brain is first tuned to the abstract rules of society and then selects these type of details
In that case, the person is selecting what they want to see in a deeper level, and the brain is narrowing all the impressions it absorbs, because the eyes themselves can't do this selecting , the brain does it through that type of process, which is very complex.
but is all that we see not real? I think it is a matter of attribution, misinterpretation, assumption and narrowing rather than constantly seeing an illusion, we create the illusion ourselves, though the C's say that our brain is our most powerful tool if we know how to use it.
If three people are seating in a room and the question comes, what color is the table, and everyone says red, and it happens that the reflection of light from the table happens to be what we call the red longitude, in the mind of the three people, the multiple processes reach multiple connections to the many associations formed when the phenomena was instituted as "red color" and "table" , for the sake of keeping it simple, we seemed to have learned this in a similar way, in childhood, so we can access this set of associations, and agree almost instantly that this is color red.
The original associations to red can also later be replaced by other sets of associations, but memory aids the process of recognition it seems by any means necessary if we create the necessity, such as when we are competing "how many red things in the room?" type of challenge. This seems to be a form of narrowing , the fear of loosing the competition, aids the narrowing of perception, people will name all the red things in the room and ignore its texture, if is has a broken piece, if it was dirty, if it had some irregular shape.
The concept of table, is also another one that other than a human being, would probably not aquate or attribute the meaning we intended, it is wood that was shaped to serve multiple purposes of our human experience, we call it table, but we don't spend much time contemplating the many dimensions that this has.
It seems we can do this tuning at a superficial level, what interests me is the idea of emotional imbalances and crooked perception of things over all in what sometimes seem unrelated events. A person with learning problems, can have any number of interruptions, we call learning problems also a number of things to encapsulate a phenomena that affects the multiple stages or learning and construction of our machine of perception (our mind and personality).
In that sense I think that we can to some degree tune our mind (re-shape the structure of our various layers of perception) and achieve a better configuration and therefore a better perception more complete and whole, which obviously includes all life experiences, and even then our eyes are not designed to see EM waves, meaning we have biological limitations, the psychological limitations, that express themselves in all sorts of imbalances cause many errors of perception which affect all bodies and ultimately perception
We are talking , that this re-shaping of the structure of our being is an enormous work, we have the tools of the work to relate to it for the sake of familiarity, so I think it is important to remember that we are talking about mayor changes even at the fundamental level. an almost impossible feat.
With this comes the idea that we would not be able to hold the pressure of all reality if we were to get a glimpse of it, we would not be able to see all. We are also talking about that constructing our being to process and organize external influences more objectively takes lifetimes and encompasses all our lives.
How this relates, in evolutionary terms, and in terms of densities is a more difficult question, because I think our perception grows as it learns and we all learn, not something that can be answered at your "natural selection" lecture easily, but I think important to understand and answer the question of illusion.
In material terms I think the illusion is liked to our limitation in perception which affects primarily the moving center and it is the baseline of our whole experience, this means that if a person had echolocation , or deaf, a chunk of whole would be different than everyone else, but doesn't limit them to interpret certain aspect of reality and identify the missing link.
Interesting subject. :p