Self-discovery by Vladimir Savchenko

Author:Vladimir Savchenko [Savchenko, Vladimir]
Language: eng
Format: epub
Tags: sf
Published: 1979-03-19T05:00:00+00:00

Chapter 13

In Lieu of an Epigraph

“The theme of today's lecture is: why does the student sweat at exams? Quiet, comrades! I suggest you take notes — the material is on the subject…. Thus, let us examine the physiological aspects of the situation that all of you present have had to experience. The oral exam is on. The student through various contractions of the lungs, thorax, and tongue is creating air vibrations — answering his question. His visual analyzers control the accuracy of his response by the notes in his hand and by the nods of the examiners. Let us sketch the reflex chain: the executive apparatus of the second signal system utters a phrase — the visual organs register a reinforcing stimulus, a nod — and the signal is passed to the brain and supports the stimulation of nerve cells in the proper part of the cortex. A new phrase… a nod… and so on. This is often accompanied by a secondary reflex reaction: the student gesticulates, which makes his answer all the more convincing.

Meanwhile the unconditioned reflex chains operate on their own, inexorably and unconstrainedly. The trapezoid bone and broad muscles of the back support the student's body in an upright sitting position — as natural for us as the position of walking was for our predecessors. The chest and intercostal muscles maintain rhythmic breathing. Other muscles are tensed just enough to counteract gravity. The heart beats evenly; the sympathetic nervous system has stopped the digestive process so as not to distract the student. and everything is in order.

But now the student registers a new aural stimulus through his eardrums and membranes of the ears: the examiner has asked him a question. I never tire of observing what follows — and I assure you, there is no sadism in this. It's simply pleasant to watch how quickly and clearly, taking the millions of years experience of our ancestors into account, our nervous system reacts to the slightest hint of danger! Look: new air vibrations first bring on the end of the previous activity of the unconditioned reflexes — the student stops talking, often in mid — word. Then the signals from the hearing cells reach the medulla, excite the nerve cells of the rear tubers of the lamina tecti which commands the unconditioned reflex of caution: the student turns his head in the direction of the examiner! Simultaneously the signals of the aural stimulus branch off into the diencephalon, and from there into the temporal lobes of the cortex, where a hurried meaning analysis is undertaken of the air vibrations.

I want to direct your attention to the high expediency level of the location of the analyzers of aural stimuli in the cortex — right next to theears. Evolution naturally took into account that a sound in the air moves very slowly: some 300 meters a second, almost the same as the speed of signals traveling along nerve fiber. Yet a sound could be the rustle of a lurking tiger, the hissing of a snake, or — in our times — the noise of a car careening around the corner.

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