Experimental Cognitive Psychology - Essay Example

Outline the assumptions, advantages and disadvantages of the following methods and evaluate their contribution to the study of human cognition: experimental cognitive psychology; cognitive neuropsychology; computational modeling. During the past few years remarkable progress has been made in the science of human cognition, the branch of psychology that studies perceptions, memory, and thinking. The greatest strength of cognitive psychology is the fact that it makes use of experimental research, studies-or brain damaged patients, computer simulations, and advanced techniques for studying the brain. Cognitive psychologists have made numerous contribution to the study of understanding the process and structures involved in perception, attention and performance, memory, language and thought. These contributions have taken various forms, leading researchers to identify three main strands in the cognitive psychology : Experimental cognitive psychology: This approach relies largely on laboratory - based studies of cognition in human individuals. Cognitive neuropsychology: This approach involves studying cognitive processes in brain-damaged patients to understand the workings of the cognitive system. Computational modeling: This approach involves producing computer programs to mimic the processes and outputs of the human brain; it is a very precise approach, because full details of how a cognitive task is performed need to be spelled out in the program. Here we would be discussing each of the above mentioned methods: their assumption, merits, demerits and their contribution to the study of human cognition. Experimental Cognitive Psychology: For many years, nearly all research in cognitive psychology involved carrying out experiments on healthy individuals under laboratory conditions. Researchers have shown great ingenuity in designing experiments revealing the processes involved in attention, perception, learning, memory and so on. As a result, the findings obtained by experimental cognitive psychologists have played a major role in the development and subsequent testing of most theories in cognitive psychology. Experimental cognitive psychology was for many years the engine room of progress in cognitive psychology as a whole, and other approaches have derived benefit from it. Moreover, the selection of tasks by cognitive neuroscientists for their brain imaging studies is influenced in part by the theoretical and empirical efforts of experimental cognitive psychologists. A striking success of experimental cognitive psychology has been the way its approach has influenced several areas of psychology. For example, social, developmental and clinical psychology has all become decidedly more "cognitive" in recent years. Finally, the methodological contributions of experimental cognitive psychology should not be under-emphasized. Experimental cognitive psychologists possess many well-worked-out empirical methods built up over 100 years of experimentation. In spite of its numerous successes, experimental cognitive psychology possesses various limitations, few of these would be considered here. The greatest limitation of experimental cognitive psychology is that it is often rather artificial. This occurs because most experiments are carried out under highly controlled conditions in a laboratory. As a result, such experiments often lack ecological validity, meaning that they cannot be applied to everyday setting. Besides, experimental cognitive psychologists obtain measures of the speed and accuracy of task performance. These measures provide only indirect evidence about the internal processes involved in cognition and about their relationship to each other. Moreover, if we are to understand human cognition fully, we need to know what is happening in the brain. This cannot be achieved by experimental cognitive psychology on its own, because it lacks the techniques to study the brain directly. Experimental cognitive psychologists have often put forward theories expressed only in verbal terms. As a result, these theories tend to be somewhat vague, making it hard to know precisely what predictions follow from them. Another limitation of experimental cognitive psychology is the reluctance to take individual differences seriously. The typical research strategy involves using analysis of variance to assess statistically the effects of various experimental manipulations on cognitive performance, with individual differences being related to the error term. Cognitive Neuropsychology: Cognitive neuropsychology is concerned with the patterns of cognitive performance (intact and impaired) shown by brain-damaged patients. According to cognitive neuropsychologists, the study of brain-damaged patients can tell us much about normal human cognition. Human cognitive neuropsychology is, however, much more than catalogue of different problems that brain injury can give rise to. As an approach to understanding the mind and the brain, cognitive neuropsychology is both old and new- old to the extent that the issues it addresses are ones which have exercised the mind of philosophers, psychologists, neurologists and others for hundreds, even thousands, of years; and new because it is only within the last fifteen years or so that cognitive neuropsychology has become established and has articulated its distinctive approach. The philosopher of science, Imre Lakatos, has argued that every science has at its core a set of assumptions which are not directly testable (Lakatos, 1980). These assumptions may be right or they may be wrong - the only way that the scientist working in a particular area will know whether the whole approach advances or flounders. As cognitive neuropsychology has become established in recent times, so its practitioners have sought to identify some of the core assumptions upon which it rests. Modularity is one of the core assumptions of cognitive neuropsychology - something which can never be ultimately proved or disproved, but upon whose validity the enterprise as currently articulated rests. Another key assumption, following Shallice (1988) is isomorphism. This is the assumption that there is some correspondence between the organization of the mind and the organization of the brain. In the words of Michael (2000): " the discovery that the various capacities which independently contribute to intellectual performance do correspond to the spatial distribution of cerebral mechanisms represents a step towards the recognition of similar organization in neurological and mental events". However this assumption is not the one that neuropsychologists in all periods have been willing to make. Another assumption of cognitive neuropsychology is the assumption of transparency, which requires that " the pathological performance observed will provide a basis for discerning which component or module of the system is disrupted" (George, 1985). That is, careful analysis of intact and impaired performance and the pattern of errors shown by a patient after brain injury must be capable of leading us to valid conclusions about the nature and functions of the impaired processing components. The important assumption that the performance of a brain-injured patient reflects the total cognitive apparatus minus those systems which have been impaired is termed as the assumption of subtractivity. In most areas of cognitive neuropsychology, it has proved possible to find a number of patients exhibiting rather similar patterns of impairment. It is then possible to replicate findings from a single case or patient by using further single cases. This approach provides more convincing evidence than can be obtained from a single patient. The findings from individuals patient differ from each other is an advantage in some ways, because it means that the underlying theory is exposed to different tests. Few of the limitations of neuropsychology are discussed below. It is typically assumed that the cognitive performance of brain-damaged patients provide reasonably direct evidence of the impact of brain damage on previously normal cognitive systems. However, some brain-damaged patients may have had somewhat unusual cognitive systems prior to brain damage. In order for cognitive neuropsychology to make rapid progress, it would be ideal to find patients in whom brain damage had affected only one module. In practice, brain damage is typically much more extensive than that. When several different processing modules are damaged, it is often hard to interpret the findings. Moreover, the modular approach may exaggerate the extent to which cognitive functions are localized within the brain. Therefore, even complex cognitive functions for which a modular description seems apt rely on a number of interconnected brain regions or systems. The entire cognitive neuropsychological approach is very complex, because there are often large differences among individuals having broadly similar brain damage. Prior to brain damage these individuals may have had diverse life experiences. Afterward there life experiences likely vary too, depending on the type of rehabilitation they receive, there attitudes towards therapy and recovery and their social support network. Finally cognitive neuropsychology has often been applied to relatively specific aspects of cognitive functioning. There has been a substantial amount of work on the reading and spelling of individual's words by brain damaged patients, but rather little on the comprehension of texts. Computational Modeling: Computational Modeling involves programming computers to model or mimic some aspects of human cognitive functioning. Computational cognitive scientists develop computational models to understand human cognition. A good computational model can how us that a given theory can be specified and allow us to predict behavior in new situations. Computational modeling is based on three different types of theories define by computational psychologists. First, computational psychologists adopt a functionalist approach to the mind, in which mental states are abstractly defined in terms of their causal role (with respect to other mental states and observable behavior). Second, computational psychologists conceive of the mind as a representational system, and see psychology as the study of the various computational processes whereby mental representations are constructed, organized, interpreted and transformed. And third they think about the neuroscience in a broadly computational way, asking what sorts of logical operations or functional relations might be embodied in neural networks. These three process oriented characteristics constitutes a minimal definition of "computational psychology". One of the major benefits of the computational models developed in computational cognitive science is that they can provide a explanatory and a predictive basis for a phenomenon. Cognitive scientists use flowcharts as a sort of plan or blueprint for a program, before they write the detailed code for it. This overcomes the limitations of experimental cognitive where the theories are stated in vague verbal statements. The computational modeling of psychological theories provides a strong test of their adequacy, because of the need to be explicit about every theoretical assumption in a computational model. Another advantage of computational modeling is that it supports the development of more complex theories in cognitive psychology. In many cognitive theories, theorists can rapidly reach a point where the complexity of the theory makes it very hard to say what the theory might predict. If you have developed a computational model, then the predictions can be generated rapidly and easily by simply running the model with the target stimuli. Another advantage to the computational models have been proposed as general cognitive architectures that can be applied to the understanding of all cognitive functioning modeling is the clarity it can bring to the comparison of theories. Cognitive science is perhaps the fullest expression of the computational metaphor of the mind. However, there are many individuals who oppose it on certain basis. It is argued that, computational models are rarely used to make predictions; they are produced as a prop for a theory, but have no real predictive function. For any given theory, there are a large number of possible models and these variations are rarely explored. It is a matter of some concern that findings obtained from neuroimaging studies sometimes seem inconsistent with those obtained by cognitive neuropsychologists with brain - damaged patients. The techniques for measuring brain activity used by cognitive neuroscientists have become progressively more sophisticated and sensitive. These advances have sometimes had the paradoxical effect of making it harder to decide which areas of the brain are most involved in specific functions. CONCLUSION : The greatest strength of cognitive psychology is the fact that it makes use of experimental research, studies on brain-damaged patients, computer simulations, and advances techniques for studying the brain. In general terms, looking at human cognition from four different angles is likely to increase our understandings much more likely at it from only one angle. In addition, it is reassuring to discover that many key assumptions of cognitive psychology have been confirmed by all approaches. However, there are few limitations to each of these approaches. REFERENCES : Booth Paul, 1989: Introduction to Human-Computer Interaction, pg 216. Psychology Press (UK) Ellis Andrew & Young Andrew, 1996: Human Cognition Neuropsychology, pg 117. Psychology Press (UK). Eysenck Michael, 2000: Psychology: A Students Handbook, pg 32. Psychology Press (UK). Knapp Terry, 1986: Approaches to Cognition, pg16. Lawrence Erlbaum Associates Lakatos Imre, 1980: The Methodology of Scientific Research Programmes, pg 91. Cambridge University Press. Mandler George, 1985 : Cognitive Psychology: An Essay in Cognitive Science, pg 17 Lawrence Erlbaum Associates. Parkin Alan J, 1996 : Explorations in Cognitive Neuropsychology, Psychology Press (UK). Shallice Tim, 1988: From Neuropsychology to Mental Structure, pg 7. Cambridge University Press. Temple Christine,1997: Developmental Cognitive Neuropsychology, Psychology Press (UK). Tomasello Michael, 2001: The Cultural Origins of Human Cognition, pg 72. Harvard University Press. Read More