Our sound files are in RealAudio format.  For more information click here.

Stereoscopic Vision

Click here to listen to this feature

Although we take two well spaced, front facing eyes for granted, they give us our ability to perceive depth, and see the world in three dimensions.

Because of the space between our eyes, the image from each eye takes in more of the outside edge of its field.  With each eye looking at things from a slightly different angle, we see some of both sides of an object at the same time, with the two images superimposed on each other.

This gives us a gift of stereoscopic vision, so our world does not appear flat.  The brain takes the information that is received from each eye and uses it to estimate our distance from the object.

Many creatures like, fish for example, do not have stereoscopic vision.  Others, like the owl, have both stereoscopic vision and telescopic vision.  This means that they can see small, distant objects even in poor light.

As with so many of our perceptions of the world, our mind interprets information that it receives from our eyes.  If someone walks towards you from a distance, they don’t look as if they are growing as they approach you.  Our mind keeps distant people the same size, by making a series of mental adjustments to familiar figures.  A camera, which doesn’t make this mental adjustment, will produce pictures in which the person nearer the camera looks bigger than the person in the distance.

So next time you look at something, be sure to keep both eyes open, and trust your brain’s interpretation.

MOVING BEYOND MATTER
 by Debbie Hughes

Vision is an interesting sense.  I’ve always wondered about babies’ vision.  What do they see?  Is their eyesight clear or fuzzy, simple or complex?  What do they see when they dream, assuming they do dream?

There are actually two aspects of the sensing process.  First, there is the actual physical stimulation which is carried to the brain along nerve pathways.  This may be an image captured on the retina, or soundwaves upon the eardrum, chemicals to the taste buds or olfactory nerves, or stimulation to nerve endings in the skin.  This is the sensation itself. And secondly, there is the experience of that sensation.  Perception is that mix of incoming information (the actual sensation), combined with our emotions, expectations and previous experiences.

While sensation may be measured in a rather objective fashion (for example you can actually measure how loud music is, using units called decibels), the perception of it is a personal experience.  Music may be perceived as pleasing or grating, as melodic or dissonant.  And although there are broad categories upon which most people would agree, we are uniquely tailored by our genetics and our environment.

The sensitivity of our personal sensory settings and our associations with sensory input, all contribute to a highly personal experience of our world.  Perhaps this is why people are able to draw different conclusions even in the face of similar experiences, perhaps even the same experience. 

Now the meaning that we draw from our experiences is based upon the categories in which we have come to understand life.  And what we find shapes the contours of our personal philosophy.  Deep in the human psyche, there is a desire for coherence, for having a big picture of life, so that our experiences are not disjointed.  It is worthwhile to give some thought to your view of the human landscape - who we are and where we're headed.