It is such a natural experience to us that we hardly notice our almost total suspension of disbelief in the artifice of form, volume and depth. Would a 15th Century mind experience this image the same way we do?
Our world is awash with visual representation in ways that Early-Renaissance Europe undoubtedly was not. While our on-board neuroanatomical and image-processing hardware may not may not have changed all that much in the 500 years since this image was created, the internalised software and operating system(s) of culture, language and communication have undergone dramatic, persistent and accelerating upgrades over this same period.
A contemporary experience of visual culture is mediated by the distributed presence of so many artefacts that in their presence manifest as an encoded rules-set and playbook for cognition, comprehension and communication. Visual culture is in this sense not merely the sum total of all instances of art and communication, it is a repository for the ways of seeing (and understanding) that in their record and encoded form provide not just the content or the message and meaning of art, but also hold the evolving rules through which that art might be interpreted and understood.
We are not more intelligent than our predecessors but our intelligence has been displaced into a material environment in ways which would have been all but entirely unintelligible to them. It makes you wonder if our internal psychological worlds have become substantively poorer in direct (and inverse) proportion to the extent that our immediate experience and cognitively-extended technological and representational environments have become exponentially richer.
Art: silverpoint by Leonardo da Vinci.