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2007-9-26
Conditional Reflex is formed based on the Unconditioned Reflex in individual life, or trained through experiments. For example, that a dog secretes salivary when feeding him is called Unconditioned Reflex, and food is the unconditioned stimulus . Use bell rings stimulus to a dog, saliva is not secreted at all because the bell ring has nothing to do with feeding which is called indifferent stimulus. But use ring stimulus first and then distribute the food before feeding, and repeat it time and again, you will find the dog also secretes saliva when using bell ring separately. After repeated tests combining bell ring and food, the indifferent stimulus of the bell ring that replaces the signal of food, has turned conditional stimulus. And the reflex caused is called conditional reflex. In daily life, frequent combination of indifferent stimulus and unconditioned stimulus can lead to conditional stimulus and thus establish conditional reflex, which is called reinforcement. When the Conditional Reflex is set up, impose frequent conditional stimulus instead of the reinforcement of the unconditioned stimulus, the Conditional Reflex shall gradually get weakened and even deprived of, which is called the retrogression of Unconditioned Reflex. The newly built Conditional Reflex is easy to retrogress without consolidation, which requires constant reinforcement to stabilize. It's the same with the learning process of the human being. We need to repeatedly review and strengthen what weĦŻve learned and able to obtain solid knowledge.
We still have no clear idea of the forming mechanism of the conditional reflex, and it's supposed that the signals of unconditioned stimulus and conditional stimulus transmitted have set up temporarily functional relations among the centers at each level. Such relations in human and some intelligent animals can be built through the cerebral cortex.
Reflex is generally classified into two major categories, Unconditioned Reflex and conditional reflex. Conditional Reflex is also divided into First Signal System Reflex and Second Signal System Reflex pursuant to the nature of the signal system.
Unconditioned Reflex is the congenital reflex from birth, which is a comparatively inferior nervous activity completed and participated by the nerve center (such as spinal cord, cerebrumstem) under cerebral cortex. Knee jerk reflex, blink reflex, withdrawal reflex, sucking reflex, micturition reflex, etc. are all included into Unconditioned Reflex. Plum is a sour fruit that enables to secrete salvia at one bite. Such reflex is innate and self-taught, which belongs to Unconditioned Reflex.
Conditional Reflex is acquired in daily life after birth, which is a superior nerve activity based on Unconditioned Reflex, completed and participated by cerebral cortex after a certain progress. It is the basic means of higher nervous activities. One who regularly eats plum will secrete salvia when he sees it. This is what he completes based on the experience of eating plum, which is classified as Conditional Reflex. Just imagine what would happen if Cao Cao's soldiers had never eaten plum and not been told they were sour.
Based on the types that cause Conditional Reflex, it can be divided into First Signal System Reflex and Second Signal System Reflex. Reflexes caused by specific signals of visual, acoustic, tactile, olfactory, gustatory senses, are called First Signal System Reflexes, which jointly owned by human and animals.
During the struggle between mankind and the nature, with language developed in races and cerebrum evolved, the speech center was formed in cerebral cortex. As a result, Conditional Reflex is built on some abstract speeches and letters, which characterizes the mankind and belongs to Second Signal System Reflex. The saying "quench one's thirst by thinking of plums" is a typical example.
The process of building Conditional Reflex is like this: singly impose the indifferent stimulus (such as bell ring) for a few seconds, then combines the unconditioned stimulus (such as feeding) to jointly work for a certain duration. After several repetitions, the sing use of the indifferent stimulus can trigger the reaction caused by unconditioned stimulus (such as salvia secretion). Now the bell ring has become the conditional stimulus of salvia secretion, which constitutes the Conditional Reflex.
Unconditioned Reflex is the basis of Conditional Reflex. Conditional Reflex enhances the adaptability of animals accustomed to the nature. The more advanced the cerebrum is, the more complicated Conditional Reflex is built.
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Organizer:
Beijing Municipal Association for Science & Technology
Undertaker: Beijing Science & Technology
Consulting Center,
Information Center of Beijing Municipal Association for
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