|
Freethought
Association of West Michigan
Meeting Minutes for August 14, 2002; #121
Jeff announced
that our group has now passed its five- year mark and is still
going strong. We also continue to remain a non- "prophet"
group.
The American
Atheists are organizing a "Godless March on Washington"
in early November. This march to promote national awareness of
a much maligned and/or ignored segment of the population, is open
to interested members of atheist, agnostic, and freethought group
members or individuals. FAoWM member, Frank Bacon is trying to
see who is interested in going to our nation's capital for this
event via chartered bus. Contact him directly or through the group
for more information.
Our next meeting
will feature group member, Buddhist and juggler, Steve Anderson,
as he presents "Meditation for Heretics" on August 28.
See our website, www.freethoughtassociation.org for more schedule
and other information.
Our meeting
topic this time was "The Neurological Basis of Consciousness"
and was presented by group member, Herman Sullivan, M.D. We can
understand consciousness via neurobiology, i.e.- through investigation
of brain function. The complexity of consciousness is characterized
by the complexity of the brain itself. We can perceive this in
different species and can also see how brain damage affects the
consciousness of the individual in our own.
Dr. Sullivan
took us through an exploration of brain structure and sensory
apparatus to see how the incoming sensations are captured, relayed
and interpreted by the various parts of the brain. During this
part of his presentation, he focused on the thalamus as an important
mediator of consciousness, as it has a vital role in sensory relay
and communication with the cortex. We next turned to brain mapping
and in particular the connections with occipital cortex cells
and ones in the eye, the route traversed and how different parts
of visual consciousness are derived from specific areas that ultimately
converge upon a coherent interpretation of the world around us.
We looked
at work done by William James and the Gestalt psychologists as
Dr. Sullivan focused more on visual constructs for understanding
consciousness. Vision is easier to measure and allows us to peer
into how we create our conscious awareness. It also was a way
that we could see for ourselves how we do this by way of several
interesting images he showed the group. Some were optical illusions,
which served to show how the various parts of the brain combine
information to organize visual stimuli into certain interpretations.
We tend to perceive certain elements from different visual cues
of arrangements, orientations or proximities as portraying specific
outcomes or realities. The brain reads into the image what it
"should" be seeing (as well as filtering out extraneous
data) and we are surprised when these natural biases are manipulated
to fool us as in optical illusions. In this vein, we saw how full
images were completed from partial information, how distortions
snapped into recognizable patterns by slight modifications and
how our brains fill in the "blind spot" in our visual
field. In one illuminating example of this, a dot can be placed
in a neutral field and when we train our eyes upon an adjacent
spot, placed so that our blind spot is in the same place as the
dot, the dot disappears; filled in with the surrounding color
of the background. This is what is happening all the time and
why do not perceive a hole in our vision. Dr. Sullivan showed
us how even a line that is broken becomes connected by this same
filling in process when the break appears in the area of our blind
spot.
We looked
at how contrasts are perceived by examples of uniformly toned
circles appearing darker or lighter than ones next to them depending
upon the background tonality. Our visual system creates continuous
linearities out of broken lines by seeing the discontinuity as
an occlusion by overlapping or other such tactics. Our brains
create shapes that fit expectations in other examples presented.
The perception of perspective is strongly created with the right
visual cues from flat surfaces-distances and recessions, orientations
of objects to expected light sources (light usually comes from
above: the sun. overhead artificial lighting, etc.) and so on
all are constructs in the brain. We perceive edges with more definition
than our visual acuity would account for and even auditory sensations
are filled in with anticipated outcomes-an example being a person
speaking while another sound covers up a word in the speaker's
sentence. We believe we heard the uttered word, though this is
not the case.
Dr. Sullivan
showed how attention and memory fit into our visual consciousness
by some additional presented images. Next we were taken through
the actual chemical/ molecular process of perceiving the environment-processes
that take in not only the rods and cones (incidentally, the location
of the light sensitive rods in the eye explain why we see shining
objects with more clarity when we look slightly off-center from
the object) but also that of photo- transduction, and chemical
changes that take place when different illumination levels or
orientations of objects are presented to the viewer. Specific
structures are in place to perceive certain types of visual information-for
instance horizontals or verticals, curves, contrasts, size, motion
and so on-all processed out of the incredible amount of visual
information being assembled out of whether cells are triggered
on or off, layer upon layer of saturation of disparate pieces
of data that become a coherent, unified visual experience. As
Sullivan said, we do not require mystical explanations for visual
consciousness; the complexity of our neurological reality is sufficient.
Each neuron-and there are as many neurons in our head as there
are stars in our galaxy-is connected to thousands of others and
these are further interconnected…the computation that takes
place in interpreting our environment is staggering to contemplate.
Simple cells adding tiny bits of information, parallel inputs
eventually resolving, all coalescing into a magnificent whole
and all seemingly effortless to us.
In our discussion
portion, we reviewed some of the information presented, including
how the components that are widely distributed throughout the
brain collectively form our consciousness. We also discussed "free
will" and the evolutionary process that would make us more
likely to perceive some things more than others, or make different
associations from the same external data than if we had gone down
a different evolutionary route. We discussed how actual brain
structure is altered from experiences as well as injury and how,
therefore, conscious interpretation of the world is also changed.
The incredible parsing of information that goes on continuously
to form consciousness was compared to the waves upon an ocean
that we readily perceive, while the vast depths are hidden from
our general awareness.
Secretary:
Charles LaRue
|
