Human Cognition — Ch. 1 (Guenther)

Guenther, R.K. (1998). Human Cognition. Upper Saddle River, NJ: Prentice Hall. (Chapter 1)

This chapter provides a nice overview of relevant historical and contemporary theoretical perspectives on what constitutes the mind and how we acquire and react to stimuli. Initially, scientists and philosophers assumed there was a supernatural or spiritual quality to the mind (vitalism, dualism), but discoveries made in neurophysiology and the acceptance of the theory of evolution provided evidence for a more materialistic view of mind and thinking. Once scientists believed that the mind was governed by biological/physiological processes, it allowed them to investigate “thinking” through empirical research and hypothesis testing. Up sprang various fields of study, all falling under the umbrella of “cognitive science”: cognitive and developmental psychology, cognitive neuroscience, cultural anthropology, physical anthropology, linguistics, artificial intelligence, etc. Work in AI had a profound effect on the direction of cognitive science, as many computer scientists sought to model thinking and consciousness, promoting an information processing approach to cognition.

More recently, “biologically-realistic” models of human cognition have been proposed — neural net models, connectionist models, and parallel distributed processing models. They all incorporate the anatomy of the brain, with its complex network of neurons. Such a model aligns with various observable aspects of cognition, such as late-onset dementia and the limits of working memory. This “external stimuli-internal response” paradigm led to a strong behaviorist movement. Behaviorists did not bother themselves with internal mental processes. However, it turns out that examining such internal processes (i.e., adopting a mechanical view of causality) does appear to be necessary in order to fully understand and describe cognition.

[*Note: Much of the following material was excerpted from the chapter…]

Human cognitive psychology – an inquiry into how people acquire and use knowledge.

1543 – beginning of the demise of the supernatural viewpoint. Polish astronomer Nicolaus Copernicus (1473-1543) published thesis that the sun, not the earth, is the center of the solar system (heliocentric theory). About a century later, Galileo (1564-1642) championed the heliocentric theory.

Isaac Newton (1642-1727) discovered the laws of motion, which he described with mathematical equations, and speculated about the cosmic machine. Newton, and others before him, notably Johann Kepler (1571-1630), imagined that the cosmos ran something like a giant clock that, once wound, was self-regulating and so could run itself without the need for divine intervention. James Hutton (1726–1797) applied Newtonian principles to the geology of the earth and concluded that natural
forces, like erosion or the gradual uprising of land formations, shaped our world’s landscape. The earth’s present-day features have their origin in natural, not supernatural, forces. And so the physical, inorganic universe became natural, and humankind’s place in that universe became ordinary.

The 1800s saw an explosion of knowledge about biology and physiology. Hermann von Helmholtz (1821-1894), one of the founders of modem experimental physiological psychology, argued against a widely held view called vitalism that maintains that life requires the presence of a life force whose nature is not physical but spiritual. Helmholtz was able to demonstrate that food and oxygen consumption could account for all the energy an organism is able to expend.

Arguably the most important biological insight of the 1800s was the theory of evolution proposed by people like Chevalier de Lamarck (1744-1829), Alfred Wallace (1823-1913), and Charles Darwin (1809-1892).

Might it be the case that the rest of the biological world and even human bodies are governed by natural,
physical processes, but human minds remain outside the natural realm? Most famous proponent of this view was the  French philosopher and scientist Rene Descartes (1596-1650).

Dualism — reality consists of two parts: (1) ordinary matter that occupies space and behaves according to physical laws; and (2) a radically different substance that does not obey ordinary physical laws and does not occupy space but, instead, has as its main feature the capacity to think.  The brains and bodies of humans and other animals are made of matter and so may be regarded as physical mechanisms. What we
call the human mind is made of this nonspatial thinking substance. Thus, human mental phenomena are caused not by physical processes in the brain but by the autonomous actions of a nonmaterial, spiritual substance that has the capability of affecting the human brain. The brain is only the medium through which the thoughts of the mind affect the material world.

Descartes’s version (also called substance dualism), claims that the mind-substance can exist independently of the body.

Property dualism – complex brain brings into existence the mind, which then has emergent properties
unlike those that characterize the physical world. A mind cannot exist independently of a brain.

All versions of dualism make the important claims that the mind is fundamentally nonmaterial, does not obey physical laws, and can serve as the original cause of actions taken by the body.

Descartes believed that the apparent ability of the mind to initiate actions on its own, independently of the body, is the most important dissimilarity between the mind and physical processes. A physical process never really initiates action. There must always be an antecedent physical process that gives rise to it. “I think, therefore I am.” The body’s existence can be doubted but the mind’s existence cannot be
doubted, therefore the body and the mind must constitute different realms of reality.

Dualistic views of the relationship between the mind and the body seem to provide a kind of loophole for the supernatural perspective on the human mind. The entire universe, even the human body, may be properly regarded as natural, but not the human mind, which is not part of the physical world and so not governed by natural law. Thus dualism denies the possibility of a cognitive science that is in any way analogous to the physical or biological sciences.

But a belief in dualism introduces a perplexing complication. It is obvious that events in the physical world can affect a person’s mental state. One response a property dualist might make is to concede that the brain causes the nonphysical mind to come into existence; consequently, if the brain is degraded by
damage, it would follow that the mind would be degraded as well. But there still remains the problem of how a nonphysical mind can affect the brain. If the mind is nonphysical, what gives it the capability of interacting with the physical world of neurons and muscles? This is the problem of mind-body interaction and it is one that Descartes and other dualists have never been able to solve to the philosophical community’s satisfaction (Churchland, 1988).

Discoveries in the field of neurophysiology and the doctrine of evolution spawned a widespread rejection of dualism and a growing consensus favoring materialism – the mind is simply a label for the way the brain functions. The materialist sees no reason to claim that there is a separate realm of reality called the mental realm that stands apart from the physical realm; instead, there is only the physical brain whose function
it is to do things we label mental.

Cognitive science – the mind reflects only the physical processes of the brain, so that the methods of hypothesis testing and experimentation that have proven fruitful in other sciences are useful for the study of human mental life as well. Cognitive science, the scientific study of mental processes, is really an umbrella term subsuming several allied approaches to the study of human mental life.

Psychologists working in the 1800s became especially interested in developing a connection between neural and cognitive processes. Much of this work was (and still is) done in the area of perception.

Cognitive psychology – study of the functional properties of human cognition.

Cognitive neuroscience – study of the physiological underpinnings of cognitive phenomena.

Franciscus Danders (1818 – 1889) — decision “subtraction tests”

Hermann Ebbinghaus (1850 – 1909) — fxnal properties of memory

Sigmund Freud (1856 – 1939) — psychodynamic psychology

20th century: great advances have been made in our understanding of how different portions of the brain contribute to perception, the control of sleep and wakefulness, control over voluntary movements, memory, motives, emotions, and the use of language. Much of the progress in cognitive neuroscience has been due to the development of new technologies such as the electroencephalogram (EEG), recording
of the electrical activity of single neurons, the deliberate destruction of small sections of the brains of animals, and the imaging of blood flow in the waking brain.

Cultural anthropologists like Claude Levi-Strauss and Stephen Tyler began the study of the relationship between culture and mental processes as revealed in cultural metaphors, classification schemes, and folk stories.

Physical anthropologists like Louis Leakey (1903 to 1972), his wife Mary Leakey, and their son Richard, relying on new techniques like radioactive dating of fossils and artifacts, began to reconstruct in some detail how humans and human cognitive traits evolved from the more apelike species that lack many of our cognitive capabilities.

Linguists Noam Chomsky and Edward Sapir (1884 to 1939), began to develop detailed models of the grammars of the world’s languages; models of how people learn, use, and understand language; and models of the relationship between grammar and the thought processes of the language user.

Developmental psychologists began to study how a child acquires cognitive skills. The 20th century’s most influential developmental cognitive psychologist was Jean Piaget (1896 to 1980), who claimed that cognitive development proceeds through a series of distinct stages.

The invention of the programmable computer inspired another approach to cognitive science, usually called artificial intelligence or AI. AI also helped shape a theoretical approach to cognitive psychology called information processing. The idea that human thought processes are like the transmission of information in artificial devices is known as the information processing approach to human cognition.

Four claims of information processing:

  • any cognitive process consists of the transmission of information through a series of stages in which the information is transformed, in order to achieve some goal.
  • higher mental processes, like reasoning or language, can be understood as the collective action of a set of very elementary operations.
  • human cognition has a limited capacity for storing and transmitting information.
  • there are especially apt analogies between human thought processes and digital computers. Humans, like computers, require for their intelligence the activation of rules that manipulate symbols.

Biologically realistic models of human cognition are variously called neural net models, connectionist models, and parallel distributed processing models. The input units often correspond to perceptual neurons that detect physical features of stimuli (e.g., the bitterness in beer), the output units correspond to motor neurons that control movements (e.g., drinking the beer), and the hidden units correspond to association neurons that intervene between perceptual and motor neurons. Sometimes the output units correspond to making a decision, such as deciding whether a face is male or female or whether a beer is an ale or porter.

Neural net models can be used to explain various aspects of human cognition, such as how we remember and sometimes forget past events and why the capacity to process information is limited.

A neural net model, like a real brain, has no program that controls what the model does, nor does it have a central processing unit (CPU) that carries out the symbol manipulations that constitute the program. Instead, the behavior of a neural net model depends on the current configuration of connections among its units and not on a set of explicit rules. To put it another way, symbols and rules are replaced by the overall pattern or configuration of connection strengths among a network of units. The behavior of a neural net model, like that of a real brain, is not radically altered by the malfunctioning of one or a few units. That is because neural net models contain a large number of units acting to simulate the large number of neurons in the brain. Neural net models are said to degrade gracefully. On the other hand, the loss of the CPU or of one of the rules contained in a program of a computer would ordinarily be catastrophic for the computer system.

Probably the most important function of neural net models is that they illuminate the neural processes underlying the components that make up any information processing model. The neural net approach more directly simulates the dynamics of the interactions among neurons that give rise to a short-term memory with limited capacity.

Materialism asserts that all cognitive processes, and the behavior based on them, derive from physiological mechanisms in the body and the external stimuli that impinge on the body. One implication some psychologists have drawn from materialism is the doctrine of behaviorism – environmental stimuli control behavior, which increases in probability if reinforced. Well known behaviorists include John Watson (1878 to 1958) and B. F. Skinner (1904 to 1990). Behaviorists eschew explanations that make use of mentalistic constructs like “information manipulation,” memory,” or “feelings.”

Behaviorists feel that here is no need to postulate complicated internal mental processes in order to predict or control human behavior. Behaviorists do not deny that people have memories or other conscious experiences, but they claim that there is no point to developing models of these processes because they do not increase the ability to predict and control behavior.

The cognitive psychologist’s response to the behaviorist claims is based largely on what is called a mechanical view of causality, which specifies the mechanisms whereby stimuli force or compel behavior or outcomes. The mechanical approach usually details a chain of antecedent processes that bridge the gap between stimulus and response. The cognitive psychologist prefers the mechanical approach to causality because it seems a more satisfying and complete analysis of a phenomenon.

Furthermore, and despite behaviorist claims to the contrary, the mechanical approach yields predictions in situations in which a purely behaviorist analysis fails to produce predictions. However, sometimes, the successful prediction of the effect of a stimulus on behavior requires postulating an intervening mental process. many behaviors can be understood only if one examines the processes that intervene between stimulus and response.

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Comments
One Response to “Human Cognition — Ch. 1 (Guenther)”
  1. Brian says:

    I truly enjoyed reading this posting.Thanks.

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