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Excerpt:
Wolf Singer: "The hierarchy of the senses"p. 62 "That leads me to the question whether our senses, that transmit our primal perception, differ in respect to our persuasiveness. Do we trust our eyes more than our sense of haptics or sense of hearing? It appears to me that the greatest reliability is allowed our sense of haptics, or tangible perception. What we can grasp is perceived as real, therefor our term "grasping" (begreifen). After all all our experience regarding the body is grounded in this sensorial system.
There are topographical maps in our brain that depict the space around us. These maps are supplied with information by our visual and our auditory system. These two maps have to precisely cover each other to locate the origin of a sound auditory as well as visually and to align the two. If we would not align these two maps with each other, it could happen that we see a dog to our right but would hear its barking from the left, which would confuse us tremendously.
Now the alignment of different sensorial maps is not a trivial problem, from a perspective of evolutionary biology (entwicklungsbiologisch). These maps develop independently from one another and have to be adapted later. This adaptation evolves through experience. Babies learn over time to align the different maps of their sensory perception. Now we could ask: Which adapts to which, the acoustic map to the visual or vice versa? It is considered as true (?evident?safe?) that the visual map is established first and the acoustic map is adapted later. Through this we may derive that greater reliability is accredited to the visual system and the acoustic system has to adapt itself to it."
Ventriloquist:
" ... the listener has the convincing impression that my speech came from the location where the motion is created. That is because our nervous system aspires to align the different sensorial modalities with each other and associates the source of speech to the kinetic movement and rightly so . One does not only think that the source of sound is at the location of movement, but in fact does hear speech emanate from there."
To the organisation of our cerebral cortex.
"Now there are different positions, neurobiological equivalents that our different systems of senses take upon a "gamut of trustability" (Überzeugungsskala)? Here the organisation of our senses on the level of our cortex is especially interesting as this is the structure responsible for all our higher cognitive achievements.
We are talking about the 2 Millimetre thin coat of cells that covers our cerebral cortex. It consists of densely packet nerve cells of which 60 000 are to be found on one cubic Millimetre. Each of these cells is connected to about 20 000 other cells. Nerve cells communicate most intensely with their immediate neighbours but they also provide connections to nerve cells in other far away regions of the brain."
(...)
p.68 "Where does the brain takes the sureness?? that what it perceives is in fact what is being transmitted by the sense organs?"
p.68 "If it is possible to achieve by artificial or manipulative actions that different signals of the senses were perceived as aligned, then the brain has no chance of distinguishing that it has been tricked. Systems that create virtual realities proof this in impressive manner. A pilot in a flight simulator experiences visual impressions just as if he was flying. He also perceives sounds and feels vibrations and accelerations as if he was sitting in a plane. After a few seconds the awareness of sitting on the firm earth and not being exposed to any dangers is suppressed. The pilot reacts to crises with the same dismay as he would do in reality. Many may have made the same experiences in IMAX-cinemas. When many systems of senses affirm the same, one becomes convinced that it is so."
(...)
p.71 Where is the central switchboard?
"Only a small percentage of cells in the primary sensorial areas receives signals from the sensorial organs. The cortex is obviously primarily busy with itself." Signals from the environment are only loosely interlinked. Every single one of the many areas works on different parts of aspects and sends the results of the individual operations to others."
The bonding problem:
"How can a system of such distributive organisation create coherent images of the world? How does it manage to organise the multitude of partial results to a whole? We describe this problem as the "bonding problem" and we do not have reached a solution providing consensus."
Laws of Gestalt: Closure, continuity, coherent movement and similarity." The text continiues on pattern recognition.)
Conclusive remarks:
p.75 "The brain is a highly active self referential system that falls back upon innate (internal) knowledge; that, based upon stored information - genetical as well as those acquired during biological evolution - creates a coherent image of the world - from the little that is supplied by the sensorial system.
The brain creates models of the world, compares the incoming signals with these models and searches for the most probable solutions.
Those models do not necessarily have to agree with physical reality - and in fact do not in many cases - , then it depends upon evaluating variables that are relevant for behaviour and beneficial for survival. It is of importance to be thereby as fast as possible. Our cognition is grounded in probability calculations and inferences (?).
Most intriguing is that we take the result of this interpretative action for reality. We do not realise that we construct but we believe that we picture (? reproduce). It is one of the many illusions we succumb to. Another concerns the belief that we have a centre of command in the brain that resides and assess, decided and orders. Instead we have to imagine the self (Ich) as a spatially distributed state of self organisation - something that appears neither easy nor appealing.
Additionally there is our discomfort between the incompatibility of our self-awareness (how we perceive ourself) and the natural-scientific image of ourselves. Subjectively we experience ourselves as autonomous, mental actors equipped with a free will, that decide themselves what they want to do, and that transfer this decision into neural activity, to make happen what they imagined. This point of view is less and less conformable with the results of neurobiological research. Thus we are living in two parallel worlds. In the one, that we experience subjectively we take our perceptions for reality and do not realise that we are constructing - suspecting our self at a singular location and have confidence that it is able to do as it pleases. yet from a neurobiological perspective we have to realise that these estimates and beliefs are implausible to a high degree. The future will tell how these deeper insights will be able to affect our self-perception (Selbstbild)."
Sorry for the poor quality of this quick & dirty translation.
(Another title that Nick Roericht made me read. Thanks Nick!)
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