An Introduction to Cognitive Psychology: Processes and Disorders
One example is recognition memory. If you meet a friend in the street you recognise the familiarity of their face automatically, without any apparent effort, and without needing to devote conscious attention to the task Mandler, The role played by automatic processing in familiarity judgements will be considered in more detail in Chapter 4. For example, I found during a recent car journey that instead of driving to my present house as I had intended, I had in fact driven to my previous address by force of habit. Another of my recent action slips involved absentmindedly adding instant coffee to a mug which already contained a teabag, thus creating a hybrid beverage of a highly unpalatable nature.
Action slips of this kind have been extensively documented and in most cases can be explained by the activation or perseveration of automatic processes which are not appropriate Reason, Such studies add an interesting perspective to our view of automatic processing. Automatic processes are obviously of great value to us, as they allow us to carry out routine tasks rapidly and without using up our attentional capacity.
Introduction to Cognitive Psychology - E-bok - David Groome () | Bokus
However, automatic processes lack flexibility, and when they fail to provide appropriate behaviour they need to be overridden by consciously controlled processing. There is some evidence that this override system which allows controlled processes to take over may be located in the frontal lobes of the brain, since patients with frontal lesions are often found to exhibit perseveration of automatic behaviour and a lack of flexibility of response Shallice and Burgess, a; Parkin, Frontal lobe functions will be examined further in Chapters 6 and 7.
Conscious awareness We all have conscious awareness. This means that we are aware of our perceptions, our thoughts, our memories and our actions. We can all therefore understand what is meant by the term consciousness as a subjective experience, yet no one has yet been able to provide an explanation of what conscious awareness actually is, or how it might arise from neural activity. Consciousness remains the last unexplored frontier of psychology, and arguably one of the greatest mysteries of life itself.
However, although we do not understand what consciousness is or how it arises, we are beginning to learn something about what consciousness does, and the part it plays in cognitive processes. As explained in the previous section, psychologists have recently devised methods of distinguishing between processes which are consciously controlled and those which are unconscious and automatic.
Although this research has focused mainly on the nature of automatic processes, it has also shed a certain amount of light on the conscious processes which sometimes replace them. Tests of explicit memory and implicit memory have also been used to distinguish between conscious and unconscious memory retrieval Schacter et al. The study of patients with certain types of brain lesion has provided particularly valuable insights into the nature of conscious and unconscious cognitive processes.
For example, the occurrence of blindsight in patients with occipital lobe lesions Weiskrantz, has demonstrated that some patients can detect visual stimuli at an unconscious level, despite having no conscious awareness of seeing them.
Blindsight will be examined in more detail in Chapters 2 and 3. A similar phenomenon has been observed in amnesic patients, who often reveal evidence of previous learning of which they have no conscious recollection whatsoever. These studies of amnesia will be discussed further in Chapter 5. Autism is another type of disorder which has shed light on the nature of consciousness, because autistic individuals appear to lack some of the characteristics of conscious processing.
Their behaviour tends to be highly inflexible and repetitious, and they usually lack the ability to form plans or generate new ideas spontaneously. They also tend to lack the ability to develop a rapport with others and to disregard other people, treating them as though they were merely objects. This may provide a clue about some of the possible benefits of having consciousness. Other theories of consciousness have tended to emphasise the distinction between controlled and automatic processing.
It is argued that consciousness provides us with some extra level of flexibility and control over our cognitive processes, whereas unconscious automatic processes tend to be rigid and stereotyped. Norman and Shallice suggest that automatic processes can provide adequate control of our neural functions in most routine situations without needing to use up our attention, but they must be overridden when more complex tasks require the flexibility of conscious control.
Crick and Koch argue that the flexibility of this conscious control system stems largely from its capacity for binding together many different mental activities, such as thoughts and perceptions. Baddeley suggests that conscious control may reside in the central executive component of the working memory see Chapter 4 , which is largely associated with frontal lobe function.
Johnson-Laird compares consciousness with the operating system which controls a computer. He suggests that consciousness is essentially a system which monitors a large number of hierarchically organised parallel processors. On occasion these processors may reach a state of deadlock, either because the instructions they generate conflict with one another, or possibly because they are mutually dependent on output from one another.
Our understanding of consciousness is still very limited. However, the little knowledge we do have about consciousness provides an excellent example of the integration of ideas from all three of the main approaches to cognitive psychology. Integrating the main approaches to cognition The three main approaches to cognition are experimental psychology, computer modelling and cognitive neuropsychology. However, it is the integration of these three approaches that has led to the emergence of the modern science of cognitive psychology.
The combination of these three related approaches provides the subject matter of the rest of this book, and will be applied to each of the main areas of cognitive processing in turn. These areas are perception, memory, thinking and language, and there will be a separate chapter on each of these processes. A unique feature of this book is that each chapter on a particular cognitive process will be followed by a chapter dealing with disorders of that process.acponfeme.tk
An introduction to cognitive psychology: processes and disorders. 2nd edition
In this way it is intended that the relationship between normal cognition and cognitive disorders can be fully explored. It includes the study of perception, learning, memory, thinking and language. They are experimental cognitive psychology, computer modelling of cognitive processes, and cognitive neuropsychology.
Further reading Neisser, U. Cognitive Psychology. New York: Appleton-Century-Crofts. This book provided the main starting point for modern cognitive psychology. Obviously well out of date now, but still of historical interest. Payne, D. Boston, MA: Houghton Mifflin.
A book on normal cognition, but rather unusual in that it includes several mathematical approaches to cognition, such as signal detection theory. Parkin, A. Explorations in Cognitive Neuropsychology. Oxford: Blackwell. A detailed yet readable account of the main forms of cognitive disorder, with chapters on aphasia, agnosia and amnesia. Gives fairly thorough coverage of recent research in these areas.
Crick, F. London: Francis Crick embarks on a scientific search for the soul. Despite the whimsical title this is a very scientific account of the study of consciousness, and it is by no means an easy read. Chapter 2 Perception and attention 2. Perception progresses from sensation i. In addition, the perceptual system needs to be directed in some way towards those stimuli in the external world which need to be selected for further processing.
The inherent limitations on our cognitive processing abilities, coupled with the great richness of the environment in which we live, makes it impossible for us to fully process all of the objects that may impinge on our sense organs. This selection process is referred to within psychology as attention, and this topic is considered in this chapter alongside perceptual processing.
For the purposes of the present discussion, visual processing is emphasised. To some extent this reflects the inherent bias of the human brain which devotes far more capacity to vision than it does to any of the other senses. However, clear analogies exist between visual perception and perception in those other sensory modalities.
The visual system The general structure of the visual system is illustrated in Figure 2. The starting point for the visual system is the eye which, in principle, is very similar to a camera. The receptor cells are far too numerous to each send their own axon to the brain. Instead, groups of receptor cells are gathered together to form overlapping, differently sized receptive fields. All retinal cells project to the optic disk at the back of the eye where they join with other axons to form the optic nerve.
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The optic nerves of each eye converge at a point called the optic chiasm. The optic chiasm organises the flow of information from the left and right halves of the visual world, referred to as the left visual field LVF and the right visual field RVF respectively. Fibres then project along the optic tracts to the lateral geniculate nucleus LGN of the thalamus. From here axons are sent along the optic radiations to the visual cortex. All the sensory systems, with the exception of olfaction smell , synapse initially in the thalamus.
This large brain structure is thought to have, amongst other functions, a key role in causing the organism to orient, or attend, to a particular stimulus. The LGN of the thalamus has two types of cells in layers called the parvocellular layers and the magnocellular layers because they contain small and large cells respectively. Receptive fields that connect to the parvocellular layers are called the P pathway, whilst receptive fields that connect to the magnocellular layers are called the M pathway.
These two pathways have functional as well as structural differences. M pathway neurons are mainly sensitive to movement and direction, whereas P pathway neurons are mainly sensitive to colour. Each type of cell responds to a particular stimulus so that parallel processing of multiple attributes of stimuli, such as movement, detail and colour, starts to occur very early on in visual processing. Damage to the visual pathway Damage can occur at any level in the visual system.
Referring to Figure 2. Individuals with visual field impairments may be aware of what they see because involuntary eye movements nystagmus occur and these cover for the blindspots. Cortical blindness results from damage to the primary visual cortex of the brain. It can result in the inability to distinguish forms and patterns but the patient may still have awareness of light. Primary visual processing Primary visual processing occurs in the primary visual cortex which is in the occipital lobe of the brain.
It is also referred to as striate cortex. Hubel and Wiesel , discovered cells of the visual cortex that respond preferentially to stimuli with linear properties lines and bars. Simple cells are smaller than the other types of cells and are excited by lines in a particular orientation, the images of which fall on a particular part of the retina. The larger, complex cells respond to the position and movement of a stimulus as well as to lines of particular orientations, in this case anywhere on the retina. Most complex cells are binocularly driven.
Hypercomplex cells respond to more complex features such as corners and junctions. Columns of cells in the primary visual cortex respond best to lines of a similar orientation so, for obvious reasons, are referred to collectively as orientation columns. However, orientation of lines is not the only feature of a stimulus that is analysed in early visual processing; we have seen that processing of colour and movement also starts early on.