Got the Paul Shepard reader yesterday, bringing my attention back to an issue that I haven't explored in some time, the evolution of human consciousness. Shepard's main idea is that we are endowed with the genetic heritage of our Pleistocene ancestors. Our minds, bodies and genes are adapted to the hunter/gatherer lifestyle. In his essay titled The Eye, Shepard explores how the human eye evolved and the possible influences our unique vision had and has on our unique mental ability's and artistic proclivities.
He starts by talking about how what became the primate eye evolved mainly in the Sea, before the first amphibians. This sea-eye was carried by reptiles and early mammals, who for the most part neglected vision while emphasizing smell (think of a dog, with its nose in front, dominating the face). The emphasis on one organ, the nose, lead to an "elaboration of the cerebrum....whose enlargement was begun for receiving, mixing, analyzing, and storing information from the nose." (Shepard, 2) This elaboration is a step towards to the explosive growth of the human cerebral cortex. When the first arboreal primate ancestors evolved, they put the mammalian eye back in a context similar to that of the sea. Gravity is used for orientation, sensed by the eye and endolymphatic fluid in the labyrinth of the ear. Horizontal lines are used as guides (the seafloor and surface, the horizon and branches) for both marine and arboreal creatures.
Once adapted to the trees, early primates evolved stereoscopic vision; the snout shrank and the eyes came to the fore as the dominate organ. You can get an idea of the process by looking at the lemur, who is in between a tree shrew and a monkey as far as dominance of eyes and recession of nose. Stereoscopic vision allows good depth perception through the mechanism of the ciliary muscles which can tilt the lenses in our eyes to focus on objects at varied distances. (Shepard, 6)Color vision evolved the allow us to discern bright fruits in an other wise monochrome world. The keen eyes of these creatures lend themselves to the ability of acute observation, foresight (should I approach it or not) and remembrance of past events. Primate eyes are freed from instinctual signal response, and allowed to examine and interpret its whole environment.(Shepard 11)
The next step is the use of vision by arboreal primates to acquire information from one another. Primates could develop social organization that is learned rather than inherited. This began the process of delaying development to allow for a longer learning period. Communication through para language (body language) developed, with much concentrating on the eyes (tears, furrowed brows, squinting when angry, eyes wide open when concerned, rolling eyes). Movement in the three dimensional arboreal realm required quick decision making and planning ahead by prediction based on past experience. This development will allow terrestial man to develop cultural traditions.
Shepard also discusses how the stereoscopic vision we inherited can explain some of our aesthetic sensibilities. Our affinity for horizontal and vertical lines and our tendency to follow them can be related to concentration on horizontal (horizon, branch) and vertical (tree trunk) that were necessary for balanced movement in the trees. Children enjoy climbing and it seems to be natural. The artist is highlighting or manipulating an image or part of their environment that creates an emotional reaction in their nervous system. This reaction may be felt by others observing it.
He closes with an explanation of how vision works like the other cycles of ecology. Sight begins when energy (light) penetrates our retinas. This energy is translated into "...an electrochemical code of impulses to the brain." (Shepard, 18) This translation is powered by energy we obtained from food which originated in photosynthesis. So our eyes evolved to observe the world and the order in it, which structures our brains and allows us to reflect this order in our art.
Good stuff, Eh?
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