Introduction
Imagine a young man, Knut, sitting at his desk, with his tired eyes staring at a monitor, surfing around, trying to find some worthy articles for his psychology homework. A cigarette rests between the middle and index fingers of his left hand. Without looking, he stretches out his free hand and grabs a cup of coffee located on the right of his keyboard. While sipping some of the cheap discounter blend, he suddenly asks himself: "What is happening here?"
Around the beginning of the 20th century, psychologists would have said, "Take a look into yourself, Knut, analyse what you're thinking and doing," as analytical introspection was the method of that time.
A few years later, J.B. Watson published his book Psychology from the Standpoint of a Behaviorist, from which began the era of behaviourism. Behaviourists claimed that it was impossible to study the inner life of people scientifically. Their approach to psychology, which they assumed to be more scientific, focussed only on the study and experimental analysis of behaviour. The right answer to Knut's question would have been: "You are sitting in front of your computer, reading and drinking coffee, because of your environment and how it influences you." Behaviorism was the primary means for American psychology for about the next 50 years. One of the primary critiques and downfalls of behaviorism was Noam Chomsky's 1959 critique of B.F. Skinner's "Verbal behaviour". Skinner, an influential behaviourist, attempted to explain language on the basis of behaviour alone. Chomsky showed that this was impossible, and by doing so, influenced enough psychologists to end the dominance of behaviorism in American psychology.
As more researchers were once again concerned with processes inside the head, cognitive psychology arose on the landscape of science. Their central claim was that cognition was information processing of the brain. Cognitive psychology did not dispose the methods of behaviourism, but rather widened their horizon by adding levels between input and output.
Modern technology and new methods enabled researchers to combine examinations of public actions (latencies in reaction time, number of recalls) with physiological measurements (EEG and event-related potentials, fMRI). Such methods, in addition to others, are used by cognitive science to collect evidence for certain features of mental activity. From this, references and correlations between action and cognition could be made.
These correlations were inspiration and thenceforwards the main challenge for cognitive psychologists. To answer Knut's question the cognitive psychologist would probably first examining Knut’s brain in that specific situation. So let's try this!
Knut has a problem, he really needs to do his homework. To solve this problem, he has to perform loads of cognition. The light is gleaming into his eyes, transducing it from his retina into nerve signals by sensory cells. The information is passed on through the optic nerve, crosses the brain at the lateral geniculate nucleus to arrive at the central visual cortex. On its journey, the signals get computed over complex nets of neurons; the contrast of the picture gets enhanced; irrelevant information gets filtered
out; patterns are recognized; stains and lines on the screen become words; words get meaning, the meaning is put into context, analyzed on its relevance for Knut's problem, maybe stored in some part of memory. At the same time an appetite for coffee is creeping from Knut's hypothalamus, a region in the brain responsible for controlling the needs of an organism. The appetite, encoded in patterns of neural information, makes its way to the motor cortex where it is passed on to the muscles into Knut's arm.
A lot more could be said about this, and Knut's question remains unanswered, but this should be enough to point out the complexity of cognition and the brain's importance. In this chapter, we are going to dig deeper into the question of what cognitive psychology is and how it became this way, and then draw connections to the brain and explain some of its most important parts.
Defining Cognitive Psychology
Cognitive Psychology is a psychological science which is interested in various mind and brain related subfields such as cognition, the mental processes that underlie behavior, reasoning and decision making.
In the early stages of Cognitive Psychology, the high-tech measuring instruments used today were unavailable. The idea of scientifically scrutinizing what was going on in a human mind was first established during the late 19th century.
Psychology Laboratories were based on measuring observable features such as reaction time. Nonetheless, there was a technique developed called analytic introspection. The latter is a method that focusses on the subject’s inner processes. Here, the subject has to give precise reports about his or her mental activity.
During the first half of the 20th century and naturally parallel to behaviorism, the behavioristic approach became the main issue in psychology. The main emphasis was the examination of outer expression of inner processes, rather than the mind itself.
Even though behaviorism had established itself as the mainstream, curiosity about the mind was not diminished. In the 1950s, this inquisitiveness was released in a new science named Cognitive Science. Cognitive Psychology became one of its subfields. The interdisciplinary approach of Cognitive Science enabled the use of modern technology and new methods to combine examinations of public actions (latencies in reaction time, number of recalls) with physiological measurements (EEG and event-related potentials, fMRI).
Hereby, references and correlations between action and cognition could be made. Cognitive Psychology is using these methods and additional ones such as Single and Double Dissociation and brain lesioning to collect evidence for certain features of mental activity. Because of those correlations that were found, the examination of the human brain and its functions has become one of the main challenges to Cognitive Psychology.
Chapter 1
The role of the brain
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Examination of brain damage has a long tradition. The Ancient Romans observed that gladiators with head injuries often lost their mental skills, whereas injuries to other parts of the body did not have such an effect. It was inferred that there was a possible link between the mind and brain. Today, the assumption that the mind is somehow implemented in the brain is taken for granted, and even the common-sense understanding presupposes a relation between mental and neuronal processes. Subsequently, research on the brain became more and more important, and the psychological methods being used shifted to systematic scientific examination of the brain. The crucial question then became: How is this e^ relation realized, and what properties of the brain wmreshold (-55 mV) is passed, the cell depolarizes and
capable of causing mental and cognitive events? the polarity reverses up to +40 mV. Subsequently the
cell hyperpolarizes and the voltage becomes more As it is not possible, in this introductory passage, to negative than the resting potential for a short period. cover the entire configuration of the brain in an appropriate manner, we will just give a brief summary of the concepts behind neural signal transduction, and smoothly switch over to the anatomy of the brain. This in turn will then serve as background information in the attempt to link cognitive functions to brain structure.
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1.1 - The resting potential is initially around -70 relative to the outside of the cell. Once the
In principle, there are two classes of cells in the human brain: neurons and glia. Both are approximately equal in distribution, though neurons seem to play the main role in information processing. The actual signal transduction takes place in different ways. On the one hand, there is mean electrical conduction, and on the other hand, there are complicated biochemical cascades which transmit the data. Both variants can be subsumed to the concept of action potentials (Figure 1.1), which generally carry out the signal transduction from one nerve cell to another.
For better conduction, the axons of the neurons are insulated by a so-called myelin sheath. The myelin in the human brain is produced by a certain class of glial cell, the oligodendrocytes. This is important because the decomposition of the myelin sheath is involved in diseases, such as as multiple sklerosis.
Once the information perceived by the sensory organs is transformed into a sequence of action potentials the data is, in a way, neutral, since it has no specific qualitive properties which indicate from which sense the signal was original initiated. But how is the information encoded? In other words, how can the variety of our conscious experience be caused by simple inhibition and excitation of nerve cells embedded in an admittedly complex system? Because of the lack of better metaphors, the answer is often given by comparing the brain to a modern digital computer. Parsing the world into objects, making inferences, having associative memory and the like can be analyzed by developing computational models. The underlying paradigm is that the information is represented by the rate of action potential spikes. How this is exactly realized is the aim of research of biophysics, a subdiscipline of neurobiology.
In cognitive psychology, however, the methods used differ. This is because the main interest is not devoted to the organization of single neuron circuits, but rather to the larger, functional units in the
network.
References
• M. S. Gazzaniga, R. B. Ivry, and G. R. Mangun, Cognitive Neuroscience, Norton & Company, 1998, ISBN 0393972194
• E. Br. Goldstein, Cognitive Psychology, Wadsworth, 2004, ISBN 0534577261
• M. W Eysenck, M. T. Keane, Cognitive Psychology, Psychology Press, 2005, ISBN 1841693596
• M. T. Banich, The Neural Bases of Mental Function, Houghton Mifflin, 1997, ISBN 0-395-66699-6
• E. R. Kandel, J. H. Schwartz, T. M. Jessell, Principles of neural science, 2000, ISBN 0-07-112000-9
Links
• PDF file of the "ethics code" of the American Psychological Association
• Cognitive Psychology miniscript by Fabian M. Suchanek
• Famous papers in the history of cognition
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