The Unexpected

Our constant change in relative position creates error in expected cycles.

Snorkeling over the coral reef, I see a vista of seemingly unmoving, unchanging corals. Starfish and sea cucumbers sit motionless on the bottom. Fish glide or hover or dash here and there. The brightly colored fish attract my attention as they glitter in the sun. Suddenly, my head turns, my eyes focus together on a single dead coral head. Even though I was not looking directly at it before - had not been aware of that particular section of the sea floor - some part of my mind was alerted. I know, after the event, I saw the dead coral rock move slightly. Dead coral rocks do not move.

I swim closer and dive down. The rock looks like a rock. I reach out to touch it and part of the rock moves again, sliding away from me. My mind refocuses and I see an octopus. It's skin has taken on the color and texture of the dead coral. Even though I am only a meter from it, it is still difficult to sort out the boundaries of the octopus. They are very good at disguise.

If the octopus had not moved, I would not have been aware of it. My mind had already formed an image of the coral reef and set up certain expectations my conscious mind was totally unaware of. Even though I was swimming, even though my eyes were moving both along the trajectory of my body and sliding back and forth over the whole vista of the reef, the mental image showed a still-life image of unmoving corals and dead coral rock sprinkled with sudden, bright movements of reef fish and the random prismatic ripples of sunlight on the sea floor.

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Although the diving mask restricted my normal vision slightly, I could still see a large area of the reef. The amount of information reaching the retina of my eyes was staggering. From the view of the millions of little cells forming my retina, there was a constantly shifting array of colors and shifting light intensities.

A single retina cell will sit quietly with its fellow retina cells until it detects a change. Some have been pre-set to send off a message to the brain when there is a shift in light frequency (a change in color) and others are pre-set to send of a message when there is a change in light intensity (from light to dark). The cell does not react to a particular level of light or color, it reacts to the change of color or light intensity. If conditions remain below the trigger threshold (i.e. the change is very slow), the retina cell does not signal the brain and, of course, the mind does not become aware of a visual image. Until the cell signals, it might as well not be there as far as our awareness is concerned.

When it does signal, the committee of cells it communicates with receives the incoming information and compares it to the information from adjacent retina cells. The information passed along from the eye cell to the brain cell is the news of a difference, a change. The eye cell expects conditions will continue at a steady state. When the conditions change, this comes as a surprise to the eye cell. The change of light is perceived by a chemical reaction within the retina cell. The cell compares the altered chemical condition with its memory of the intensity of light just preceding the change. If the difference exceeds a certain level, the cell reacts by sending off an electrical pulse to the brain.

Change in Focus