A frontier discipline that studies people's cognitive process.
It is formed by the mutual infiltration and influence of thinking science, psychology, computer science, anthropology and philosophy.
It mainly studies the nature, acquisition and structure of knowledge.
The understanding of the scope of cognitive science can also be seen from the content of cognitive science. So far, the main contents involved in cognitive science include sensory perception (including pattern recognition), attention, memory, language, thinking and representation, consciousness and so on. This seems to be a concern of psychologists, but it is also a concern of philosophers, linguists, computer scientists, neurophysiologists and anthropologists. It's just that researchers with different professional backgrounds have adopted different specific research methods for these same problems. Li Boyue, a scholar in China, pointed out that artificial intelligence, cognitive psychology and psycholinguistics are the core disciplines of cognitive science, while neuroscience, anthropology and philosophy are the peripheral disciplines of cognitive science.
Because of the complexity of cognitive system, it needs to be studied in many dimensions, and cognitive science needs to use tools and methods used in many disciplines to conduct a comprehensive study of cognitive system in a complete sense. It can be said that the achievements of cognitive science so far are closely related to its interdisciplinary research methods. However, interdisciplinary research methods have also brought many problems and challenges to cognitive science.
Cognitive science is a science that studies the information processing process of human perception and thinking, including the input of emotion to solving complex problems, the intelligent activities from human individuals to human society, and the essence of human intelligence and machine intelligence. Cognitive science is the result of the cross-development of modern psychology, information science, neuroscience, mathematics, scientific linguistics, anthropology and even natural philosophy.
The rise and development of cognitive science indicates that the research on human-centered cognitive and intelligent activities has entered a new stage. The study of cognitive science will enable human beings to know and control themselves and raise their knowledge and intelligence to an unprecedented height. The phenomenon of life is complicated, many problems have not been well explained, and there are many things to learn from. How to extract the most important and key problems and corresponding technologies from them is a long-term goal pursued by many scientists. In order to solve many difficulties faced by human beings in the 2 1 century, such as massive demand for energy, environmental pollution, resource depletion and population expansion, it is not enough to rely solely on existing scientific achievements. We must learn from biology and find new ways to develop science and technology. The expression of perceptual information is the basic problem of perceptual research, and it is also the basis of studying other cognitive processes at all levels. Where does the perception process begin? What variables in the external physical world have psychological perception significance? As a computational model of perception, what is the object of calculation? These questions about the expression of perceptual information are the first questions that both people and computers must answer when establishing any theory and theoretical model related to perception. The study of perceptual information expression can have different levels of problems, including perceptual organization, perceptual learning, perceptual dynamic memory and face recognition.
Combining the experimental research of cognitive neuroscience with the research of computer vision in computational theory, the knowledge expression and computer realization of the brain will put forward brand-new theories (or ideas) and solutions to the above scientific problems. Learning is a basic cognitive activity, a process of accumulating experience and knowledge, and a process of grasping and understanding external things in order to improve the performance of system behavior.
The neurobiological basis of learning is the plastic changes of the connection structure between nerve cells and synapses, which has become a very active research field in contemporary neuroscience. The condition of synaptic plasticity is that when presynaptic fibers and related postsynaptic cells are excited at the same time, synaptic connections are strengthened. 1949, Canadian psychologist Hebb put forward Hebb's learning rules. He hypothesized that the related synapses changed during the learning process, which led to the enhancement of synaptic connections and the improvement of transmission efficiency. Hebb learning rules become the basis of connected learning. Neural network is a widely parallel internet composed of adaptive simple cells. Kohonen proposed a self-organizing mapping network. According to the law that cooperation forms structure and competition promotes development, Harken organically combines cooperative nonlinear dynamics theory with neural network and puts forward cooperative associative memory network. Amari proposed to use differential manifold and statistical reasoning to study neural networks. On the basis of Amari theory, Shi Zhongzhi and others put forward a neural field model, which consists of a field organization model and a field effect model.
Perceptual learning is learning at the perceptual level, which mainly studies how to obtain relevant abstract data from the raw data input by low-level sensors. Perceptual learning mainly considers the method of transforming unstructured and semi-structured information into structured information through visual and auditory learning, the semantic description of images and its rapid extraction technology, as well as the attention mechanism and metacognition in perceptual learning.
Cognitive learning theory holds that there is a corresponding thinking process behind people's behavior, and we can observe the changes of behavior and infer the inner activities of learners through the changes of behavior. In cognitive learning theories, such as Ausubel's meaningful learning theory (also known as assimilation theory), the core idea is that obtaining new information mainly depends on the existing concepts in cognitive structure; Meaning learning can only occur through the interaction between new information and existing concepts in learners' cognitive structure; Because of this interaction, the meaning of old and new knowledge is assimilated. Gagne's information processing learning theory compares the learning process to the information processing process of a computer. The learning structure consists of sensory register, short-term memory, long-term memory, controller and output system. Cognitive processes can be divided into selective acceptance, monitoring, adjustment, repetition and reconstruction. In this information processing process, the key part is to implement control and expectation. Executive control refers to the influence of existing learning experience on the current learning process, and expectation refers to the influence of motivation system on the learning process. The whole learning process is carried out under the action of these two parts.
Introspective learning is a learning process of self-reflection, self-observation and self-knowledge. With the support of domain knowledge and case base, the system can automatically select and plan machine learning algorithms to better discover knowledge in massive information.
Implicit learning is a process of unconsciously acquiring complex knowledge of stimulating environment. In implicit learning, people will not realize or state the rules that control their behavior, but they will learn these rules. Since the mid-1980s, implicit learning has become the hottest and most concerned topic in the field of psychology, especially in the field of learning and cognitive psychology, and it has become one of the most important topics that will have a far-reaching impact on the development of cognitive psychology. Implicit learning has the following three characteristics:
Tacit knowledge can be generated automatically without consciously discovering the explicit rules of task operation;
Implicit learning is universal and can be easily extended to different symbol sets;
Implicit learning is unconscious, and the knowledge gained by implicit learning cannot be expressed by language system. In the process of human evolution, the use of language has divided the functions of the two hemispheres of the brain. The emergence of the language hemisphere makes human beings obviously different from other primates. Studies have shown that the left hemisphere of the human brain is related to serial, sequential and logical information processing, while the right hemisphere is related to parallel, visual and non-sequential information processing.
Language is a system with pronunciation as its shell, vocabulary as its material and grammar as its rules. Languages are usually divided into spoken and written languages. The expression form of spoken language is sound, and the expression form of words is image. Spoken language is far older than written language. Individuals learn spoken language first and then written language.
Language is the most complex, systematic and widely used symbol system. Language symbols not only represent concrete things, states or actions, but also represent abstract concepts. Chinese is obviously different from Indo-European language family because of its unique lexical syntax system, writing system and phonetic tone system, and has a unique style of closely combining sound, form and meaning. Concept is a form of thinking that reflects the unique attributes of things, and concept is closely related to words. The emergence and existence of concepts must be attached to words. Words can express other things because people have corresponding concepts in their minds. Therefore, words are the linguistic form of concepts, and concepts are the ideological content of words.
Learning Chinese from nerve, cognition and calculation gives us an excellent opportunity to open the door to intelligence. The study of cognitive psychology in China has a history of many years, and has achieved world-class research results. However, most of these studies focus on Chinese characters and vocabulary, and further discussion is needed in higher-level syntax and sentence processing. The research on the whole speech chain is not systematic enough, especially the language processing mechanism of the brain is not well known. In the field of intelligent systems, China attached great importance to Chinese computer information processing, invested a lot of money to support the research and development of computational linguistics, machine translation and natural language understanding system, and achieved a lot of important results. However, on the whole, there are still many unsolved problems in the intelligent processing of language information, and its solution must be based on the research of cognitive science and guided by new theories in order to make a breakthrough.
In 199 1, Mayeux and Kandel proposed a new language information processing model based on Wernicke-Geschwind model. The linguistic information of auditory input is transmitted from auditory cortex to angular gyrus, then to Wernicke's area and then to broca's area. The language information of visual input is directly transmitted from visual joint cortex to Broca area. Visual perception and auditory perception of a word are processed independently by channels with different sensory modes. These channels independently reach Broca area and higher-level areas related to language meaning and expression. The working mechanism of each step of language processing pathway in the brain needs further study.
Using mathematical methods to study language and find the forms, patterns and formulas of language structure can make the grammatical rules of language as systematic and formal as mathematical symbols and formulas, and can be used to generate infinite sentences. Chomsky, a famous American linguist, put forward the formal grammar of language in 1956, which laid a theoretical foundation for language information processing. In 1996, Yip and Sussman put forward the use of two-way constraint propagation mechanism in phonetics rules, which can explain how auditory signals at the nerve level correspond to symbols at the thinking level.
It is worth mentioning that machine translation involves linguistics, computer science, cognitive science, mathematics and other disciplines, and it is a frontier interdisciplinary subject. This challenging research field is listed as the top ten scientific and technological problems in the world in 2 1 century. However, as far as the achievements are concerned, the translation quality of machine translation system is far from the ultimate goal; The quality of machine translation is the key to the success of machine translation system.
Professor Zhou Haizhong, a mathematician and linguist in China, once pointed out in the article "Fifty Years of Machine Translation": To improve the quality of machine translation, the first thing to be solved is the language itself rather than the programming problem; It is certainly impossible to improve the quality of machine translation by relying on several programs to make a machine translation system. In addition, it is impossible for machine translation to reach the level of "faithfulness, expressiveness and elegance" before human beings understand how the human brain makes fuzzy recognition and logical judgment on language. These are the bottlenecks that restrict the improvement of machine translation quality. Memory is a reflection of what happened in the past experience and a maintenance of newly acquired behavior. Because of memory, people can keep their reflections on the past, make their reflections on the present on the basis of previous reflections, and make their reflections more comprehensive and profound. That is, with memory, people can accumulate experience and expand experience.
There are three types of human memory: sensory memory, short-term memory and long-term memory. After the stimulation stops, its influence does not disappear immediately, and an afterimage can be formed. The visual afterimage is the most obvious. After-image can be said to be the most direct and primitive memory. After-image can only exist for a short time, for example, the most vivid visual after-image only lasts for tens of seconds, which is sensory memory. The time interval of short-term memory is longer than that of sensory memory. The time for storing materials is only about one minute, or even shorter. Long-term memory refers to the storage of information that lasts more than one minute. Human memory can be divided into process memory and propositional memory. Process memory is a skill to maintain related operations, which is mainly composed of perceptual motor skills and cognitive skills. Propositional memory is to store knowledge represented by symbols and reflect the essence of things. Propositional memory is further divided into situational memory and semantic memory. The former is a form of memory that stores personal events and experiences. The latter is to store the knowledge of the nature of events that individuals understand, that is, to remember the knowledge about the world.
1974, Baddeley and Hitch put forward the three-system concept of working memory based on the experiment of simulating short-term memory disorder, and replaced the original concept of short-term memory with "working memory". Baddeley thinks that working memory refers to a system, which provides temporary storage space and necessary information for complex tasks such as phonetic understanding, learning and reasoning. Working memory system can store and process information at the same time, which is different from the concept of short-term memory that only emphasizes the storage function. Working memory is divided into three sub-components, namely, central executive system, visual space preliminary processing system and voice circuit. A great deal of evidence from behavioral research and neuropsychology shows the existence of three sub-components, and the understanding of the structure and functional form of working memory is constantly enriched and improved. People find that working memory is closely related to language understanding, attention and reasoning, and it contains the mystery of intelligence. Since the mid-1950s, with the rise of cognitive psychology, people have re-recognized the importance of attention in human brain information processing, and put forward several attention models. Among them, the filtering model and attenuation model of attention are representative and belong to perceptual selection model. These two models locate the attention mechanism in the perceptual stage of information processing and realize the information selection before recognition. Contrary to the perceptual choice model, the response choice model holds that the function of attention is not to choose stimuli, but to choose responses to stimuli. The model holds that all information can enter the advanced processing stage, but only the most important information will cause the reaction of the central system. The two models have different emphases. Perceptual choice model emphasizes concentrated attention, while response choice model emphasizes distracted attention. The focus of their argument is the position of attention mechanism in information processing. The central energy model of attention is produced under this background. The theoretical basis of this model is the limited processing capacity of information system. The problem of the location of attention mechanism in information processing is avoided, and the experimental results of perceptual choice model and response choice model are unified in form. But the disadvantage is that it does not reveal the information processing process involved in attention.
With the rapid development of brain imaging technology and neurophysiology research, it has become a reality to separate attention network from other information processing systems. Using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), we can accurately measure the changes of cerebral blood flow (rCBF) in different regions of the brain when completing specific attention tasks, thus determining the functional structure and anatomical position of each attention sub-network. In the early 1980s, Tresman's feature integration model closely combined the internal processes of attention and perceptual processing, and vividly compared the spatial selectivity of attention with the "spotlight". According to this model, the visual processing process is divided into two interrelated stages, namely, the pre-attention stage and the concentrated attention stage. In the former, simple features such as color, orientation and movement of visual stimuli are processed quickly and automatically in parallel, and various features are coded in the brain respectively to generate corresponding "feature maps". Each feature in the feature map constitutes the appearance of pre-attention Pre-attention processing is a "bottom-up" information processing process, which does not require concentrated attention. The position of each feature in the feature map is uncertain. In order to obtain the object perception, it is necessary to concentrate on scanning the "position map" through the "spotlight", organically integrate all the features belonging to the searched target, and realize the dynamic assembly of features. In 1989, Gray pointed out that concentration can cause synchronous discharge of neurons related to observed events, which usually shows synchronous oscillation for about 40 weeks. This discovery provides neurophysiological evidence for the feature integration model of attention.
According to the existing research results, Posner divides attention network into three subsystems: pre-attention system, post-attention system and alarm system. Anterior attention system mainly involves frontal cortex, anterior cingulate gyrus and basal ganglia. The afterattention system mainly includes parietal cortex, thalamic occipital nucleus and superior colliculus. The alert system mainly involves the input of norepinephrine from the locus coeruleus of the right frontal lobe to the cortex. The functions of these three subsystems can be summarized as direction control, guiding search and keeping alert respectively. Consciousness is perhaps one of the greatest mysteries and highest achievements of the human brain. Since the establishment of 1879 modern psychology, consciousness has become the main research object of psychology. James believes that psychology is the science of studying consciousness. However, due to methodological problems, it is impossible to conduct specific scientific research on consciousness. Behavioral psychology, which arose in the 1920s, denied the existence of consciousness. Cognitive psychology, which appeared in 1950s, once again raised the issue of consciousness, and studied consciousness from the perspective of perception and consciousness. Great progress has been made in the study of perception, but the study of consciousness and other issues is still in its infancy.
At present, it is difficult to give a unified and accurate scientific definition of consciousness. Different fields have different understandings of consciousness. Nobel Prize winner Crick believes that consciousness involves the neural mechanism of combining attention with short-term memory and can be studied by scientific methods [4]. Crick's amazing hypothesis of consciousness and his concrete suggestions on studying visual consciousness through visual attention and short-term memory have aroused the extensive interest of a large number of cognitive psychologists, neuroscientists and computational neuroscientists.
In the late 1980s and early 1990s, there was an important discovery in the study of visual physiology: synchronous oscillation was recorded from the release of different neurons. This synchronous oscillation phenomenon of about 40Hz was considered as a neural signal linking different image features. Crick and Koch put forward a 40Hz oscillation model of visual attention. It is speculated that the 40Hz synchronous oscillation of neurons may be a "binding" form of different features in vision. As for "free will", Crick believes that it is related to consciousness and involves the execution of behavior and plans. Eccles, another Nobel Prize winner, is keen on the study of consciousness. He published the philosophy of "Three Worlds" in his book "Self and Brain" co-authored with the philosopher Popper. It is believed that the world 1 includes all material worlds (including the brain), the world 2 includes the spiritual world of human beings, and the world 3 includes human social, linguistic, scientific and cultural activities. In his later works, according to the structure and function of nervous system, he put forward the hypothesis of "dendrite", which is the basic structure and functional unit of nervous system and consists of about 100 apical dendrites. It is estimated that there are 400,000 dendrites in human brain. He further put forward the hypothesis of "psychological children", and the psychological children in World 2 correspond to the tree children in World 1. Because the microstructure in dendrites is close to the quantum scale, quantum physics may be used for consciousness problems.
Consciousness is a complex problem, so it is necessary to find the breakthrough point and further study it with the available technical means. The study of consciousness can take conscious and unconscious as the starting point to find out the differences of nerve-related substances in brain activity.
In fact, there is also an emotional system, which has shown an active research trend in recent years. The immune system is also closely related to intelligence, so I won't discuss it here because of space limitations.