Cohen 

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Hemispheric Asymmetries. Asymmetries between the two halves or hemispheres of the brain can be divided into two types. An example of a structural asymmetry is the fact that the right hemisphere tends to be slightly longer and heavier than the left. An example of a functional asymmetry is the fact that language abilities are usually located in the left hemisphere. Evidence for this assertion can be found from a number of sources, such as individuals with brain damage in one or other hemisphere, and 'brain mapping' techniques that can show which areas of the brain are active during particular activities. 

Modelling – theoretical, cognitive, neurological. A psychological model is a theoretical construct which aims to help psychologists understand psychological phenomena through simplification. This is done by developing a representation that aims to represent important aspects of the phenomenon through reducing it to its essential features. By ignoring the less central aspects of the phenomenon, and focussing on a few, important aspects, the model can then help psychologists think about and explain the key processes involved in the phenomenon. This definition would apply to any kind of theoretical modelling, though models can often take a mathematical form, sometimes in the shape of a computer program. In this way, computers can be used as a tool in studying psychological processes – in particular, they are often used to study cognitive processes, such as perception. \nResearchers can use models in several ways: firstly, they would use their existing knowledge to try to identify the essential features of, for example, perception or problem-solving. Initially, this might simply be put in the form of a 'flow diagram', representing the essential stages of the psychological process being studied, with arrows to show the flow of information etc. This theoretical model could then be taken a stage further through being represented mathematically, and perhaps even written as a computer program. The program could then be run to examine predicted performances, for any given input. Researchers then compare the performances of the program with human cognitive processes, to see how closely they match. Research using such models has advantages over research directly on the brain in that it is much simpler, and is also appropiate for detailed analysis (in a way we simply cannot do with the enormous complexity of the brain's network).\nThe need for precise specification in a computer program, arguably has the merit of forcing the cognitive scientist to explain clearly exactly how every aspect of their theoretical model actually operates. This has often shown just how sophisticated apparently 'simple' human activities are – such as perceiving a cup of tea and picking it up. Modelling these activities is a considerable challenge for cognitive scientists, and has been a valuable source of insight into some of the processes involved in such typical human activity.\nThe principles of psychological modelling have also been used to develop mathematical models that represent and simplify the complex interactions withina system of neurons in the brain (referred to as neural nets). Models of neural networks work on a quite different mathematical basis from cognitive models based on a precisely specifying every action taken. Models of neural networks use a more 'associative' type of model, where the patterns of interactions between different 'neurons' leads to an output which varies according to the stimulus. By being exposed to a range of stimuli, the model can go through stages of 'learning', which may shed some light on, for example, the ways in which human language is learnt. 

Neuropsychology. Theories relating mental processes to particular parts of the body go back to the Ancient Greeks – e.g. philosophers such as Empedocles and Aristotle located the mind in the heart, whereas Hippocrates located it in the brain. Modern neuropsychology examines how neurological processes affect behaviour. Essentially, the study of relationships between brain and behaviour. This involves the study of brain function, for example by examining the structure of the brain and the corresponding neural activity within it. Another approach is to examine damaged brains, looking at the consequences of the damage for behaviour, perception, language etc.. Although correlation between a particular cognitive or behavioural deficit and damage to a specific brain region cannot be taken as conclusive evidence that this part of the brain is the 'source' of this cognitive function, it clearly demonstrates that this region plays some kind of an essential role in relation to this function. Examples of this in relation to language processing were discovered in early research performed by Broca and Wernicke, in the nineteenth century. However, it has sometimes proved remarkably difficult to localize certain mental processes, in particular memory, to specific regions of the brain. This has led to a shift of emphasis, from looking for particular locations (e.g. localisation of memory functions) towards examining brain processes involved in storage and retrieval of memories.\nIn addition to examining human brains, experiments upon animal brains are also carried out by neuropsychologists, in the hope of providing insight into human brain processes. For obvious ethical reasons, deliberate damage cannot be inflicted on human brains in order to study resulting psychological deficits from particular brain lesions, whereas current ethical/professional standards do allow this with animal studies (though not without strong disagreement from a number of quarters).\nOther methods involve electrical stimulation of human brains during surgery, performed under local anaesthetic, with the patient therefore conscious and able to report any resulting sensations (it should be noted that such research is only carried out as a by-product of necessary clinical intervention). The rate of blood flow to different regions can also shed light on neuropsychological questions, as can electrical recordings of brain activity. These techniques are 'non-invasive', such as magnetic resonance imaging.\n(see also NEUROPSYCHIATRY, under PSYCHIATRY) 

The impact of new technology on psychological research (1900-2000). The technology available for psychological research can have an important impact on the type of research undertaken, and the questions posed. For instance: 1975: Development of Beta VCR system by Sony (Japan) and the VHS system by Matsushita (Japan). The development and widespread availability of video cameras and players made observation a widely available methodology for a generation of psychologists. In part this was the result of affordability and transportability – videos were cheap and relatively unobtrusive. It was also because video is relatively easy to time-stamp, rewind and fast-forward, making careful analysis possible. Andrew Whiten, in his reply to request for information to EPoCH, stated: suspect it is not well enough recognised how far video has transformed both the observational and experimental work that I and like-minded scientists have been able to undertake in the later part of the twentieth century and since. Instead of fleeting, once-only perceptions of behaviour, the luxury of repeated viewings (at different speeds if required) has allowed us to become 'superhuman' in the new depth of analysis of complex behaviour that we can achieve.\n\n1951: UNIVAC, the first commercial computer demonstrated at the US Census Bureau in Philadelphia 1965: The Minicomputer – Digital Equipment's PDP-8 1982: The personal computer: The use of computer technology in research has had a pronounced effect in a large number of areas, including the ability to conduct large scale factor analysis (something almost unimaginable when hand calculations would mean months or years of work), laboratory experiments of, for instance, reaction time measured in milliseconds by computer, and flight and driving simulators. Statistics, testing, experimental instrumentation, artificial intelligence, and teaching are some of the areas of psychology affected by the widespread availability of computers. Computers, and more specifically the Internet, have also enabled academics to communicate and collaborate more easily. The Internet is also becoming a popular laboratory for conducting research, allowing for wide sampling of a more general population than the undergraduates normally studied.\n1975–present: advances in brain imaging. At the beginning of the twentieth century, the only way to study neuropsychology was through case studies of brain damage. In a few cases, patients would present with localised brain damage, allowing the researcher to make generalisations about the functions of specific areas of the brain based on the deficits recorded in the individual patient. Later, as brain surgical techniques advanced, researchers were able to extrapolate brain function, often again from single case studies or small groups of patients, following for instance, surgical section of the corpus callosum or lobotomy. At the same time, groups of patients with neurological disorders could be tested for cognitive deficits, yielding important discoveries for neuropsychology. However, advances in scanning technology and techniques (e.g. MRI or PET scans) at the end of the 20th century have allowed researchers to pinpoint areas of brain damage, allowing more precise, and non-invasive, studies of the links between the brain and cognitive and social abilities. Developments in measures of brain activity level and location also allow for more precise study of the neurological structures underpinning psychological function in 'normal' people engaging in everyday activities. The impact of new scanning techniques for neuropsychology has been likened to the invention of the telescope on astronomy.\n2000: The mapping of the human genome. A working draft of the entire human genome sequence was announced in June 2000, which, alongside new techniques for genetic sampling, has also made possible further studies into the role of genetics in psychological characteristics and psychopathologies. Written by: Course Team 

Surveys involve the collection of much less detailed information than case studies, but include much larger samples. Survey data can be either descriptive (finding out about certain characteristics of the group being examined) or explanatory (aiming to provide information that researchers can use to look at potential cause-effect relationships). In practise, most surveys probably have elements of both the descriptive and the explanatory, though perhaps in different proportions. This is because the survey method is comparatively weak at finding out cause-effect relationships (compared with experiments, for example), and even 'descriptive' surveys will usually aim to provide some explanations for the results. Questionnaires make up the basic type of survey, which simply ask people to answer a list of questions. Often this may involve giving them a pre-printed checklist of questions, which they fill in themselves and return, though it could also involve being asked questions by the researcher (the usual form with political opinion polls, for example). The questions can be closed questions, where the range of responses is restricted to those provided by the research, or more open-ended questions which do not limit so much the kind of response that can be given (which, however, can then be more difficult to code/analyse). There could of course be a mixture of open and closed questions. Attitude surveys could be seen as a particular specialised type of questionnaire, finding out about peoples' attitudes on a given topic, e.g. levels of crime, whether drug-taking should be decriminalised etc. This method uses an attitude scale to indicate the strength with which people hold the attitude being investigated, by presenting them with a series of questions relating to the topic. For example, with the drug-taking topic, one item might be 'criminalising drug-taking does nothing to reduce the overall level of drug use in society'. Participants would then give their response to this item as either 'strongly agree/agree/disagree/disagree strongly' etc. Correlational methods\nThis approach investigates statistical relationships between two or more variables, where there is some kind of orderly association between the variables (i.e. as one changes, the other also tends to). This can be reflected mathematically in a correlation coefficient, indicating the strength of the association. For example, a researcher might look for correlations between a child's reading age and IQ score. Note that the presence of a correlation doesn't prove that one variable is acting directly to cause the other to change, so care must be taken with interpreting these data (contrast with experiments, which are designed to reveal causal connections). 

Memory refers to our capacity to store and retrieve information. It also refers to the experience of recalling the past, in terms of images, sounds, tastes, ideas, people, and so on. Psychologists often divide memory into a number of different types. For example, short-term memory is used to refer to items recalled in the past ten or fifteen seconds, as in reading a phone number from a list, and holding it in memory long enough to make a call. This type of memory is also referred to as working memory, because of its use in holding material in temporary stores for the purposes of mental arithmetic (or similar types of processing). This type of memory is usually lost within a short period (e.g. 30 seconds), unless some kinds of special strategy are used.Long-term memory, in contrast, refers to memories that can be recalled after much longer periods: days, months, or years. Long-term memory itself can be broken up into a number of different types of memory. Semantic memory, the memory of the meanings and functions of things, is usually distinguished from episodic memory, the memory of particular events.