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Cognitive science

From Academic Kids

Cognitive science is usually defined as the scientific study either of mind or of intelligence (e.g. Luger 1994). Practically every introduction to cognitive science also stresses that it is highly interdisciplinary; it is often said to consist of, take part in, and collaborate with psychology (especially cognitive psychology), artificial intelligence, linguistics and psycholinguistics, philosophy (especially philosophy of mind), neuroscience, logic, robotics, anthropology and biology (including biomechanics).

Contents

Overview

Cognitive science tends to view the world outside the mind much as other sciences do; thus it has an objective, observer-independent existence. Cognitive science is usually seen as compatible with and interdependent with the physical sciences, and makes frequent use of the scientific method, as well as simulation or modeling, often comparing the output of models with aspects of human behavior. Still, there is much disagreement about the exact relationship between cognitive science and other fields, and the inter-disciplinary nature of cognitive science is largely both unrealized and circumscribed.

Cognitive science has much to its credit. Among other accomplishments, it has given rise to models of human cognitive bias and risk perception, and has been influential in the development of behavioral finance, part of economics. It has also given rise to a new theory of the philosophy of mathematics, and many theories of artificial intelligence, persuasion and coercion. It has made its presence firmly known in philosophy of language and epistemology - a modern revival of rationalism - as well as constituting a substantial wing of modern linguistics.

Cognitive science?

The term "cognitive" in "cognitive science" is "used for any kind of mental operation or structure that can be studied in precise terms." (Lakoff and Johnson, 1999) This conceptualization is very broad, and should not be confused with how "cognitive" is used in some traditions of analytic philosophy, where "cognitive" has to do only with formal rules and truth conditional semantics. (Nonetheless, that interpretation would bring one close to the historically dominant school of thought within cognitive science on the nature of cognition - that it is essentially symbolic, propositional, and logical.)

The earliest entries for the word "cognitive" in the OED take it to mean roughly pertaining to "to the action or process of knowing". The first entry, from 1586, shows the word was at one time used in the context of discussions of Platonic theories of knowledge. Most in cognitive science, however, presumably do not believe their field is the study of anything as certain as the knowledge sought by Plato.

Philosophy

Missing image
Thomas_Hobbes_(portrait).jpg
"By ratiocination, I mean computation." -Thomas Hobbes (1651)

Many but not all who consider themselves cognitive scientists have a functionalist view of mind/intelligence, which means that, at least in theory, they study mind and intelligence from the perspective that these attributes could perhaps (at least someday) be properly attributed not only to human beings but also to, say, other animal species, alien life forms or particularly advanced computer sytems. This perspective is one of the reasons the term "cognitive science" is not exactly coextensive with neuroscience, psychology, or some combination of the two.

Theories

Mind/brain identity theory

The mind/brain identity theory is the idea that, whatever "mind" and "intelligence" are, they are rooted strictly in the brain, and do not make use of, depend on, or interact with anything non-physical. Nonetheless, there is reasonable consensus that there is sense in talking about the organization of the mind without talking about the organization of the brain, and that cognitive scientists are not simply neuroscientists. Often the justification for this takes place by reference to different levels of analysis. A cognitive scientist is likely to assert that what he says about reasoning is true at the symbolic level of abstraction, while what the neuroscientist says is true at the physical level implementing the symbolic level (much like a computer as a physical object implements a virtual machine on which a word-processor runs). An exploration of this is found in the Chinese Room argument, which proposes a gedanken experiment to elucidate potential loci for "cognition".

Quantum mind theory

There exist several different quantum models of mind. In one class, the brain is considered a quantum machine; in another, the brain is a classical machine that reduces the universal consciousness function.

Psychology

Rendering of human brain based on MRI data
Rendering of human brain based on MRI data

Particular subtopics of cognitive science arguably include perception, attention, consciousness and memory. However, these are all long established fields within psychology, and there is a constant risk that cognitive scientists will merely reinvent discarded psychological analyses under a new vocabulary.

As described, cognitive science is an expansive field. However, it should be recognized that cognitive science is not equally concerned with every topic which might bear on the nature and operation of the mind or intelligence. Social and cultural factors, emotion, consciousness, animal cognition, comparative and evolutionary approaches are frequently de-emphasized or excluded outright, often on the basis of key philosophical conflicts. Some within the cognitive science community, however, consider these to be vital topics, and advocate the importance of investigating them.

Experimental methods

  • Reaction time: The time between the presentation of a stimulus and an appropriate response can indicate differences between two cognitive processes, and can indicate some things about their nature. For example, if in a search task the reaction times vary proportionally with the number of elements, then it is evident that this cognitive process of searching involves serial and not parallel processing.
  • Psychophysics: Psychophysical experiments are an old psychological technique which have been adopted by cognitive psychology. They typically involve making judgements of some physical property, e.g. the loudness of a sound. Correlation of subjective scales between individuals can show cognitive or sensory biases as compared to actual physical measurements.
    • sameness judgements for colors, tones, textures, etc.
    • threshold differences for colors, tones, textures, etc.
  • Brain imagery: analyzing activity within the brain while performing various cognitive tasks. Different types of imaging techniques vary in their temporal (time-based) and spatial (location-based) resolution.
    • EEG: Electroencepholography (EEG) measures the electrical fields generated by large populations of neurons in the cortex by placing a series of electrodes on the scalp of the subject. This technique has an extremely high temporal resolution, but a relatively poor spatial resolution.
    • fMRI: fMRI measures the relative amount of oxygenated blood flowing to different parts of the brain. More oxygenated blood in a particular region is correlated with an increase in neural activity in that part of the brain. This allows us to localize particular functions within different brain regions. fMRI has moderate spatial and temporal resolution.
    • Positron emission tomography PET uses a radioactive isotope, usually in the form of glucose, which is injected into the subject's bloodstream and taken up by the brain. By observing which areas of the brain take up the radioactive isotope, we can see which areas of the brain are more active than others. PET has similar spatial resolution to fMRI, but it has extremely poor temporal resolution.
    • Optical imaging: This technique uses infrared transmitters and receivers to measure the amount of light reflectance by blood near different areas of the brain. Since oxygenated and deoxygenated blood reflect light by different amounts, we can study which areas are more active (those that have more oxygenated blood). Optical imaging has moderate temporal resolution, but poor spatial resolution. It also has the advantage that it is extremely safe and can be used to study infants' brains.
  • Scores/wins/losses in games
  • Recording bodily movements in response to a task (e.g. walking towards an object)
  • Eye tracking: This methodology is used to study a variety of cognitive processes, most notably visual perception and language processing. The fixation point of the eyes is linked to an individual's focus of attention. Thus, by monitoring eye movements, we can study what information is being processed at a given time.

Key findings

(partial list)

Discovery of systemic human cognitive bias, usually credited to Amos Tversky and Daniel Kahneman, 1967. Basis of behavioral finance.

Assertion of equivalence of Euler's identity (basis of complex analysis in mathematics) with basic cognitive processes, George Lakoff and Rafael E. Nez, 2000. Basis of the cognitive science of mathematics.

Theories

Linguistics

Linguists find on one hand that humans—even the young and the uneducated—form sentences in ways apparently governed by very complicated rule systems. On the other hand, the same people are remarkably inept at identifying the rules that lie behind their own speech. Thus, linguists must resort to very indirect methods to determine what those rules might be. If speech is indeed governed by rules, they appear to be opaque to any conscious consideration.

The primary basis of Chomskyan psycholinguistics is the grammaticality judgement. A native speaker of a language is asked if a sentence is grammatically correct, independent of whether or not it makes sense. For example, the sentence 'colorless green ideas sleep furiously' is nonsensical, but is felt by native speakers of English to be grammatically correct. Collections of these grammaticality judgements are used to generate putative formal (purely syntactic) descriptions of human languages in terms of grammars. (For details, see formal language, Chomsky hierarchy.) These grammars, in turn, are held to describe the speaker's linguistic competence.

Other approaches to language - notably those known as functional-cognitive linguistics - have characterized this approach as too artificial (at least as an exclusive linguistic program), questioning the meaning of grammaticality judgements, a much too frequent emphasis on the English language, and the exclusive use of orthographic (written) rather than verbal sentences. Cognitive linguists argue that linguistic knowledge is no different from any other type of cognitive system and is subject to the same conceptualization processes; and that linguistic knowledge is acquired just like any other type of human knowledge - namely, through experience.

As of today cognitive linguistics is considered a proper cognitive approach to language rather than Chomsky's.

Artificial intelligence

Main article: Artificial intelligence

Goals

Strong AI versus Weak AI

  • simulation vs recreation

Turing test.

Theories

Symbolic vs Connectionist approaches There is some debate in the field as to whether the mind is "best" viewed as a huge array of small but individually feeble elements (i.e. neurons), or as a collection of higher-level structures, such as "symbols", "schemas", "plans", and rules. One way to view the issue is whether it is possible to accurately simulate a human brain on a computer without accurately simulating the neurons that seem to make up the human brain.

Symbolicism/GOFAI

Artificial intelligence. Turing machine. Chinese Room. Minds, Machines and Gdel.

Connectionism

Connectionism. Neural nets.

Dynamical systems

Dynamical systems theory of cognition (special application of dynamical systems theory).

Universalist Tendency

is also a proposed theoretical tendency, suspected to become prominent over the next century, in which people are expected to create overarching theories of everything that attempt to combine findings from various disciplines to explain the deeper processes of life.

Notable researchers in cognitive science and related fields

See also

External links

Definitions

List of People

Institutions

References

  • George Lakoff and Mark Johnson. Philosophy In The Flesh. Basic Books, 1999.
  • Luger, George. Cognitive science : the science of intelligent systems. San Diego : Academic Press, c1994
  • Bechtel, W. et. al. Ed. (1999). A Companion to Cognitive Science. Blackwell Companions to Philosophy. Malden, Massachusetts. Blackwell Publishers.
  • Gardner, Howard. (1985). The Minds New Science. Basic Books.
  • Baumgartner, P., et. al. Eds. (1995). Speaking Minds: Interviews With Twenty Eminent Cognitive Scientists. Princeton, New Jersey, Princeton University Press.
  • Damasio, A. R. (1994). Descartes' Error: Emotion, Reason and the Human Brain.
  • Gazzanija, M. S., Ed. Conversations in the Cognitive Neursciences. New York, THe MIT Press.de:Kognitionswissenschaft

fr:Sciences cognitives it:Scienze cognitive li:Cognisieweitesjap ms:Sains kognitif nl:Cognitiewetenschap ja:認知科学 pl:Kognitywistyka pt:Cincia cognitiva simple:Cognitive science sr:Когнитивна наука fi:Kognitiotiede sv:Kognitionsvetenskap zh:认知科学

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