Monday, March 23, 2009

Self-awareness in a cow pasture

Here's a story from the New York Times online today with, if nothing else, a gorgeous picture of a massive slime mold, or Dictyostelium discoideum, found in a cow pasture near Houston. These are amoeba that live separately as single cells until life gets tough, and then they mass together and form a multi-celled organism, with cell to cell communication, that can form a slug that migrates to greener pastures, and a fruiting body that produces spores. Its cells even undergo apoptosis, programmed cell death as needed to sculpt that organism. All of which requires signaling and communication. But what about self-awareness??

Slime molds signal each other with cAMP when it's time to aggregate; our brain cells signal with neurotransmitters. The cells in a slime mold are certainly aware of each other and of their environment in some senses, using receptors and the results of signal reception as their mechanism. They come together as a group, developing internal organization and structure. We might not want to call this consciousness--that is, our kind of consciousness, and it might seem silly even to speak of that. Yet, these Dictyostelia communicate through chemical signaling to work and function together. We might wish to say that they have no self-awareness because they have no central nervous system, whereas we have one and it involves so many cells working together to make 'thoughts'.

Yet how do our brains work, if not by similar kinds of chemical signals? Many kinds of experiments show that consciousness as we experience it is not the basis of our evaluation of circumstances and responses to them; our consciousness comes later, as a kind of monitor (however it works). But many if not most of our brain functions are done without conscious awareness. Nor is our self-awareness due to the large number of communicating cells in our brains, as many kinds of experiments and studies of brain injury have shown. That is one reason consciousness has remained so elusive to science.

So to what extent is it hubris for us to consider our consciousness a higher form of cell-to-cell signaling? Or, in line with the idea that cells, even 'primitive' or 'simple' cells are not so primitive or simple after all. That doesn't mean we understand the different kinds of self-awareness that exist--what about ants, for example?--but it does mean there is a lot to think about, as even the humble slime mold shows.

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