October 29, 2006

Sensing the World Around Us

We've talked about the contemporaries of our ancestors, modern archaea and bacteria. They communicate, replicate and socially organize into tight societies much like our own.

That is a relatively fuzzy comparison, however. One cannot entirely equate the complexities of our society with the biochemical signaling of such a simple organism. There are interesting similarities, but the argument is hardly conclusive.

At a more fundamental level, however, the comparison can be correlated. Biologically, each one of us is a direct descendant of those bacterial colonies. The framework for communication and organization was already set up for our body plan; natural selection merely condensed and implemented it.

We are each a giant walking colony of organisms; each of our trillions of cells has its own role in the larger organism, much as Donovan stated last week, and has become specialized to perform distinct operations in the interest of the larger organism (not to mention the many species of bacteria that inhabit our skin, mouth and gut). This is essentially a compartmentalized, specialist version of the basic bacterial colony.

We have muscle cells that provide the framework of motion, blood cells for nutrient dispersal and defense, cells that regulate hormone levels in the body, cells that absorb and digest nutrients, etc. Perhaps the most important of these are the nerve cells.

Nerve cells help the larger organism sense the world by distributing sensory information along a fabric of neurons (nerve cells) woven through our entire body. Eventually this information is trapped in brain cells for later use (memory).

It is interesting to note that objects we encounter in the world-fruit, pavement, pencils-have no inherent scent, feel, taste, sound or even appearance; we assign the qualities of an object according to their usefulness to us. We are nauseated by feces and rotting garbage because it is dangerous for us to consume. The "scent" of garbage was contextualized in ancient times, and our brain is genetically wired to send waves of repulsion through our body, driving us to turn away in disgust or even vomit.

Similarly, we are attracted to certain foods. Our mouths water at the smell. We are compelled to eat more of a food because its taste and texture indicate that it is nutritiously viable. Our bodies love lots of high energy, fatty foods.

The funny thing is, most of the information about the world in which we live is never "consciously" processed.

I'm sitting in the spare bedroom of my apartment typing this article. Loads of sensory information is coming in through my five senses:

I see alternating images, the keyboard, the desk and the monitor.

I feel a faint wind through my open window, the pressure of my tongue on the roof of my mouth, the chair pressing on my back, my feet on the floor, fingers exacting the pressure required to press each key and a dull pain in my head from staring at a light source for too long.

I smell the carpet, my lunch, fumes from cars on the highway, my deodorant; I hear trucks gearing down, my girlfriend shuffling papers, the cats running the hallway, the stilted clicks of my fingers tapping keys. I taste the remnants of my cereal in my molars.

I sense all of it and I haven't even left my seat. In fact, if I wasn't consciously exploring what exactly I was sensing at one time, all of these things would not pass through my conscious mind, since it is much more focused on organizing separate letters into words (lexical arrangement) and separate words into sentences and paragraphs (syntactic arrangement) to match and represent the ideas floating about in the conscious portion of my brain. It's busy writing this article.

But what else am I missing?

A hell of a lot. Food is being metabolized, waste removed, individual cells die and others are replicated, your heart beats, electronic messages race along our neurons, dumping chemical messages of pleasure or pain, telling different parts of the brain to increase quantities of this chemical or decrease quantities of that.

We never even catch wind of these processes in our conscious mind. Can you tell me how much serotonin you need at certain times during the day or under certain environmental pressures? Of course not, that process is autonomous.

Just like our reaction to, pain, or the "fight or flight" response, or sexual attraction to a potential partner. These are all chemically driven responses to the environment for protection or procreation of self that never even make it to your conscious mind, hard wired from our ancestors, reaching back billions of years to the very analogs of the bacterial colonies we discussed last week.

I talk about the conscious mind as a separate entity, and it is in a way; there is a definite section of the physical brain that it occupies. However, it is but one piece of our entire central processing unit (the brain) that has evolved to oversee the conglomerate of separate organisms we call the human body.

Originally published here.

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