Russian physiologist Ivan Pavlov observed that dog saliva secretion is a reaction to food. He also found that if the dog is repeatedly stimulated by the bell with food, only the bell without food will make the dog salivate, which is a conditioned reflex.
(1) The temptation of ringtones
Acquisition, reinforcement and generalization
Dogs will secrete saliva due to their natural physiological reaction when eating, which is an unconditional reflex. Food is an unconditional stimulus, and the dog's response is an unconditional reflex. When the dog hears the bell, it will not cause saliva secretion, and the bell has nothing to do with saliva secretion, which is called unconditional stimulation; For example, listen to the bell before feeding the dog every time. After repeated several times, the dog will salivate as soon as the bell rings. At this time, the bell has become a signal of eating, that is, conditional stimulation; Conditioned reflex is learned when the bell alone causes saliva secretion. The combination of irrelevant stimulus and unconditional stimulus in time is called reinforcement, and increasing the number of reinforcement can consolidate conditioned reflex. Conditional stimulation is not limited to auditory stimulation. All effective stimuli from inside and outside the body, as long as they are combined with unconditional stimuli in time, can become conditioned stimuli and form conditioned reflex. When one conditioned reflex is consolidated, another new stimulus can be combined with conditioned reflex to form a second-order conditioned reflex or a third-order conditioned reflex. After the establishment of conditioned reflex, there is a certain degree of conditioned stimulus effect similar to conditioned stimulus, which is conditioned reflex generalization.
Fading and differentiation
If conditioned reflex is not strengthened, conditioned reflex will be inhibited, mainly regression inhibition and differentiation. If we only do conditioned stimulation for many times without unconditional stimulation, the reaction intensity of conditioned reflex will gradually weaken until it disappears, that is, conditioned reflex will fade away. For example, dogs only produce conditioned reflex of food secretion to frequently intensified stimuli, but have inhibitory effect on other similar stimuli, which is the differentiation of conditioned reflex.
According to Pavlov, the reason of degeneration is that the conditioned stimulus that can produce excitement in the cortex has become the stimulus that causes inhibition. This kind of inhibition becomes regression inhibition, which makes the cerebral cortex produce active inhibition process. If the subsided conditioned reflex is left for a period of time without experiment, it can be recovered naturally; Similarly, if the conditioned stimulus is strengthened again, the conditioned reflex will be restored. Therefore, the regression of conditioned reflex is not the disappearance of the existing temporary connection, but the suppression of the temporary connection. Generally speaking, the fading speed is directly proportional to the stability of conditioned reflex.
(2) Learning addiction in "Skinner's Box"
Skinner is a famous American educational psychologist. He established the learning theory of operational behaviorism through animal experiments, which had a wide impact on primary and secondary education in the United States and even the world in the 1950s. Skinner's theoretical discovery began with the experiment of animal learning. He designed an experimental device called "peeling box".
Skinner's box
Skinner's Box is a metal box with sound insulation board around it and automatic recording device inside. There is a hungry mouse and a button in the box. When the mouse in the box is familiar with this new environment, it will always accidentally touch this button. Every time it touches this little button, a small piece of food will fall into the box. After repeated several times, it will press the button and get food. In order to solve the hunger problem, it will "consciously" press the button, which is a "learning" behavior.
Skinner also found that if the experimental mouse can't get food by pressing the button several times, it will stop; However, if you drop a grain of food every once in a while or irregularly after pressing the button, it will work harder than before. Therefore, Skinner added a conditional stimulus: after the mouse established the connection between the button and the food, put a small light in the box. When turning on the light, press the button and the mouse can get food; In the dark, no matter how the mouse presses the button, it can't get food. As a result, the mouse quickly learned to press the button only when the light was on.
Working condition action theory
This "learning" behavior measured in the experiment designed by Skinner is called "conditioned reflex". Reinforcement refers to stimulation that increases the probability of response or maintains a certain level of response. During the experiment, Skinner used food and small lights to strengthen the behavior of mice. Skinner distinguished two types of reinforcement: positive reinforcement and negative reinforcement. The former is that when some stimulus is added to the environment, the probability of the body responding increases; The latter is that when a stimulus disappears in the biological environment, the response probability decreases. Skinner also distinguished two sources of reinforcement: primary reinforcement and secondary reinforcement. The former is all the stimuli that can be strengthened without any study, such as food and water, to meet basic physiological needs; The latter includes those stimuli that are not strengthened at first, such as power, wealth, social status and so on.
(3) Turn on the "Thorndike Lantern"
Thorndike, an American psychologist, studied animal psychology by experimental methods and founded the connectionism theory of learning psychology. In the experiment of "The Hungry Cat Escaped from the Cage", Thorndike didn't train animals to complete some actions through guidance as before, but let them learn to open the cage by themselves.
Open the mysterious cage
Thorndike designed a cage, which was later called "Thorndike Puzzled Cage". He put a hungry cat in the cage and put the food outside the cage. To open the jigsaw puzzle cage, you need to press a hinged bed board, so that the two latches will be lifted and the slats of the door will turn to the vertical position. The hungry cat that has just been put into the cage always shows instinctive reaction, trying to escape from the cage by scratching, biting, drilling and squeezing. Through these constant efforts and attempts, it may accidentally touch the latch or step on the bedplate and crossbar to open the door to eat fish. After this situation appeared many times, the invalid action of the hungry cat gradually decreased, and she learned the method of opening the door as soon as she entered the cage. This process of trying and eliminating mistakes and finally learning an action is called trial and error learning by Thorndike.
Trial and error theory
Thorndike believes that animals will establish a stimulus-response relationship after each attempt, in which the successful response is retained and the ineffective response is excluded, which is the essence of learning. Through experiments and research on animal psychology, Thorndike put forward three laws about anthropology.
1) preview law: learners need to preview before they start learning, which not only enhances their learning motivation. If learners follow the prepared steps, they will feel satisfied in the learning process; If learners are fully prepared, but they don't follow the preparation, they will feel annoyed; If learners are forced to engage in certain activities without preparation, they will feel disgusted.
2) Practice: If you can get a reward stimulus, then the learner will repeat the learned response to enhance the connection between the stimulus and the response.
3) Rule of Effect: Any behavior that leads to satisfaction will be strengthened, while the behavior that leads to disgust will be weakened or abandoned. When learners make different responses in the same situation, those responses that are satisfied or those that follow satisfaction will be more firmly linked to this situation under the same other conditions.
(4) Epiphany of orangutans
When people encounter setbacks in the process of learning, epiphany often visits, casting the light of "inspiration" in the shadow of thinking, and bringing people hard-thinking answers. Not only do people have epiphany, but psychologist Kohler found that chimpanzees on African coastal islands also have epiphany.
The problem of obtaining bananas
At the invitation of Prussian Academy of Sciences, Kohler, a German psychologist, went to Tenerife Island, a Spanish territory off the coast of Africa, to study the behavior of orangutans 19 13 to 17. 1925, he published the book The Wisdom of Orangutans, in which the experiment of "taking bananas" was very famous.
The experiment of taking bananas was carried out in a house. There is a bunch of bananas hanging on the roof, which the orangutans can see but can't reach. There are several boxes on the ground. Kohler observed: At first, the orangutan tried to jump up and catch the banana, but it couldn't reach it, so it stopped jumping and walked around the room as if observing the things in the room. After a while, the orangutan suddenly came to the box, motionless, and after a while, it moved the box under the banana and stood on the box to catch the banana. When a box is not high enough, orangutans will also fold two or more boxes.
Epiphany learning
Koehler concluded that orangutans learned to pick bananas not by trying the wrong method, but suddenly. This learning behavior can be explained by the theory of "perceptual reorganization": the orangutan suddenly discovered the relationship between bananas and boxes, so he reassembled the existing knowledge and experience in his knowledge structure and found a new way to solve the problem. This is epiphany learning.
The causes of epiphany need to be studied. The existing viewpoints are as follows: first, epiphany depends on the situation, and epiphany is possible only when the relationship between the answer and the current situation is easy to perceive. For example, in the experiment of taking bananas, orangutans will only consider taking bananas close to the box; Secondly, after an epiphany, it can be repeated. For example, after orangutans learn to fold boxes, they will try to fold more boxes to get bananas. Therefore, Kohler believes that the learning behavior of orangutans is not to establish a specific connection between stimulation and response, but to form a cognitive relationship between a certain means and a specific purpose.