Wednesday, April 18, 2012

An art project that ran for 12,000 years

The murals within the Chauvet Cave in Southern France were painted from 32,000 years ago to about 20,000 years prior to the present, before the cave was sealed by a collapse. While the cave remained opened, some of the paintings were expanded on and added to by later artists who lived up to 5,000 years after the original painters. The timescale involved and the sheer numbers of humans who lived and passed away during that 12,000-year period is humbling. That's a span of time almost twice the age of the oldest Egyptian pyramids.

This kind of art is also an interesting milestone in tracking the development abstract human thought. Being able to create a representation of a flesh-and-blood animal from blobs of paints and strokes of a brush on a blank surface demands a lot of high-end reasoning power. The kind made possible by the memory- and concept-associating neocortex glomed on to the the front of our human brains. That and by our semantic memory system which stores abstract concepts.

Our oldest system of memory in evolution is short-term memory, which consists of transient electrical currents between specialized neurons that do not appear to last much longer than a span measured in seconds. After that, the first durable system involving permanent connections between neurons was the reflexive memory system--also known as muscle memory--which allows basic physical skills to be memorized and improved upon. Then came the rise of the declarative memory, which is a set of memory systems that can be actively accessed and searched by the parts of our brains involved in generating conscious thought.

The oldest part of this network is the autobiographical subsystem, which provides the ability to recreate images and other representions of past situations that we have experienced. A second subsystem appears to have gradually emerged to hold information that concerned positive and negative stimuli organized on the basis of positions in space rather than in time. Eventually this subsystem evolved into our semantic memory, which holds abstract concepts and the ultimate representations of abstracts, words. In doing so it lets us both store and process data that is independent of the situation in which it was learned.

Probably the most important function of our semantic memory is that it lets us identify and understand underlying cause-and-effect dynamics common to multiple scenarios. Without it, we would probably see our pasts as linear collections of wholly unique moments with no repeatable commonalities on which to base predictions.

Paintings like those in the Chauvet Cave as well as the appearance of deliberately buried bodies interred with grave goods are important markers of human sapience. Signs of an awareness of the world that extends beyond just the immediate experience of the here and now to the implications of the present and a comprehension of multiple potential futures. They are also a powerful demonstration of how the neurological systems that make them possible are a key futures of what defines both the human experience as well as who we are as individuals.

We are our present and our past. We are both the history of our genes and culture as well as our imaginings of the future.

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