METHODS 

Developmental psycholinguistics. This research method focuses on empirical study of the processes and stages involved in the development of language in children. Despite the great complexity of language, virtually all children quickly and easily reach high levels of skill in language use. Studying how children are able to do this is not only interesting for linguists learning about the structure of language, but also for psychologists trying to understand the cognitive processes underlying the acquisition and use of language. 

The Repertory Grid is a method developed by George Kelly, based on his Personal Construct theory. The basis of this theory is to examine the 'personal constructs' through which individuals make sense of their worlds. Kelly saw these constructs as being bipolar in nature – examples might be friendly-hostile, loving-hating, friendly-cold. Although this approach can be used in many ways, it is particularly relevant to how people see other people (and can also be used within therapy). Generating a Repertory Grid involves asking individuals to consider a triad of three other people they know (it could also involve three objects, or three events etc.). Kelly called these 'elements'. They then have to think of ways in which two out of the three are alike, and the third is different. For example, they may say two of them are friendly, and the third hostile. This has then produced the bipolar construct friendly-hostile. This process is repeated with different triads, eliciting a range of bipolar constructs used by that individual. \nThe next step in this method is to create a grid containing the different elements, showing the ratings people gave to each element according to all the different constructs that emerged. In the example given above, if the individual creating the grid has 'elements' consisting of his friends Bob, Jane, Sally and David, with bipolar constructs such as friendly-cold, happy-sad, lively-reserved, then the resulting Repertory Grid would say how each of his four friends rated on each of the bipolar constructs. So Bob may emerge as friendly, happy, reserved. In practice, Repertory Grids tend to contain many more elements/constructs than this example. The next step in this method is to analyse the patterns that emerge between all these different constructs. For example, an individual may believe that people who are rich are also always shallow, or that people who are intelligent are always cold. Such rigid constructs can lead to relationship difficulties, and some psychotherapists use the Repertory Grid to help find out such things about a client's construct system. The therapist and client together may then explore possible new ways of making sense of the world, either by generating new constructs, or by being less rigid in the way the client applies their existing constructs. For example, by realising that not every intelligent person is necessarily cold. \nThe idea that individuals have the capacity to change the way they make sense of the world is called by Kelly constructive alternativism, and is a central part of his theory. This emphasis on people's capacity for autonomy is one reason why Kelly is classified as a humanistic psychologist (see humanistic perspective). Central to this method is its focus on allowing people to reveal their own constructs, rather than ones presented by the researcher. For example, one person might have a bipolar construct of friendly-hostile, and someone else may have one of friendly-cold. This approach could be compared with other approaches (such as experimental), which primarily focus on making sense of people in terms of concepts generated by the researcher. Although course the very concept of seeing things in terms of 'bipolar constructs' is Kelly's own way of making sense of people's construct systems, Kelly would argue that at least individuals are encouraged to generate their own particular bipolar constructs, rather than ones imposed by the researcher. 

Neuroscience. Neurological scanning (e.g. MRI, PET) Techniques used involve neurological scanning of different parts of the brain (using complex and expensive apparatus with techniques such as Magnetic Resonance Imaging or MRI, and Positron Emission Tomography or PET). Such scanning can, for example, show which parts of the brain are active when different cognitive or emotional activity is happening. They have allowed psychologists to map the brain activity that occurs in different everyday activities.\nAnother technique measures the small electrical signals produced by the brain, using an electroencephalograph, or EEG. Different frequency ranges of signals are recorded separately, as Alpha Waves, Beta waves, Delta waves etc. Researchers have studied correlations between different brain wave activity (e.g. relative proportion of Alpha and Beta waves) with different psychological states, such as dreaming, non-dream sleep, normal waking activity, day-dreaming etc. Interesting correlations were found with things like rapid eye movement periods in dreaming (REM) and high levels of brain wave activity. Operations and case studies of brain damaged patients\nOne way of studying how different parts of the brain may be affecting human experience is to study the behavioural and experiential consequences of alterations to the normal brain set-up. Obviously, this cannot ethically be done as a deliberate experiment on humans (though it is sometimes carried out on animals – see section on animal research, and associated ethical issues). However, psychologists can study the resulting effects when this occurs in humans because of brain-damage (either present from birth, or due to injury), or surgical intervention. An example of the latter is the operation to sever the corpus callosum, which connects the two hemispheres of the brain (this is sometimes carried out to help very severe cases of epilepsy, for example). \nResearchers such as Sperry have used special equipment in the laboratory to present different tasks to the two brain hemispheres. These studies gave considerable insight into how cognitive functions such as touch and vision appear to be processed by the different hemispheres. For example, visual stimuli presented so as to be processed by the left hemisphere of the patient could be described easily. However, when presented to the right hemisphere, they could not be described, or even properly recognised in conceptual terms, although they affected the emotions. This shows how language is a left-hemisphere function (for right-handers), and is a good example of the kind of research done with this methodology. 

Genetic research. Human genetic research involves the study of inherited human characteristics. In the context of DSE212, the focus is particularly on possible insights into the origins of our psychological characteristics, including possible disorders (e.g. schizophrenia). The relationship between our genes and our individual psychology is not a simple one – there are complex interactions between different genes themselves, and between genes and the environment. The whole debate about the relative importance of biological and social explanations of human behaviour is a vigorous one within the social sciences generally. There are two main categories of genetic research – statistical and molecular – and these are described below in more detail: Statistical genetics. There are a number of different aspects of statistical genetics. Epidemiology involves the study of the distribution and origins of disease using statistical methods. Similar approaches can be used to estimate the genetic contribution to particular human disorders (or talents). In many cases, a particular genetic background doesn't provide 100% of the explanation for why a particular disorder occurs. Rather the genetic background gives rise to a stronger or weaker predisposition, which may be triggered by particular environmental or psychological factors. Statistical genetics may also be able to identify combinations of genetic and environmental risk factors that show there are particular subgroups of the general population who are at increased risk of a particular disorder.\nMolecular genetics. This method focuses on analysing the biochemistry underlying genes, and how this emerging knowledge can help increase understanding of human health and disease. Key aspects of the biochemistry of genes involve looking at how they are able to replicate and be transmitted, often in terms of the chemistry of the 'nucleic acids' DNA and RNA. The Human Genome Project is a major undertaking in a number of laboratories (particularly in the USA and Britain) to examine the location of every human gene and to examine the chemical structure of each gene, in order to find out the role the gene may play in affecting health and disease. 

Collecting, classification. This kind of approach is exemplified by the work of Charles Darwin, and provided the data he used as the basis for his theory of evolution. It basically involves travelling to different locations, collecting as many examples/instances as possible of different species (plants, animals, insects). The next step is to try to find ways of logically grouping the resulting samples in some kind of systematic classification. Animal Studies\n(incorporates 'studies of non-humans', ethology, comparative studies of animal behaviour, field observation). An obvious first question here might be 'why are studies of animal behaviour being presented in a course to do with human psychology'? The basic argument is that, with care, studies of animals can provide insight into at least some aspects of human behaviour and experience. As the discussion in the perspective evolutionary psychology argued, our evolutionary background hasn't just resulted in the particular form of our bodies, but our behaviour and experience as well (or at least some aspects of them). Comparative psychology. This approach involves comparing humans with other species, looking for common factors, for example mating patterns or aggression. Much comparative psychology has involved laboratory studies of creatures such as rats and pigeons, looking in particular at the learning of behaviours. Ethology\nThis approach, in contrast with comparative psychology, avoids laboratory work, as it aims to study animals in their natural environment, based on field observation, carefully observing different aspects and sequences of behaviour. Ethologists place particular emphasis on an extensive observational phase, before attempts are made to analyse the data. For example, studies of non-verbal communication in animals have provided insights into human gestures and expressive movements. Ethologists would, of course, acknowledge that many human gestures are culturally-specific, and probably not directly related to our evolutionary/biological heritage. Nonetheless, they would point to certain aspects of human expressions which seem to arise in most or all human societies, and which seem to have relatively clear links with animal behaviours. Ethical issues in animal research (and psychology in general)\nWith research on animals, we come to the very important topic of the ethics involved – the possible mistreatment of animals that can occur with those approaches which involve painful and/or damaging intervention in the animal's natural life.\nThe strongest argument in favour of animal research involving pain is the potential value of the research, much of which would never be allowed to be done on humans. An example might be Seligman's work on learned helplessness, which involved repeated electric shocks to dogs (one dog died as a result of the experiments). Are the resulting insights (e.g. into institutionalisation, and how to counter it) valuable enough to outweigh the possible distress to animals? To place this in context, it might be argued that the current carnivorous practices of the majority of the human race result in much greater suffering, and on a vastly greater scale, than carefully-regulated animal research. (The average battery chicken would probably cluck with joy at the thought of living in a nice, cushy animal research laboratory). However, many psychologists now feel very uneasy about humanity's easy assumption of the right to inflict suffering on other species, simply because they are less evolved than us (there might be a complaint or two if an advanced race of aliens used the same argument towards us). \nIt is interesting to see how viewpoints on this have changed over time – in the 19th century, it was thought by some scientists that animals couldn't feel pain, that their cries and other responses (to stimuli which would invoke pain in humans) were not correlated with actual feeling. This is hardly an argument that would be used today though it is perhaps instructive to reflect that it was only at the end of the 20th century that many medical practitioners were persuaded that human infants feel pain. It remains to be seen whether future generations will view our current attitudes to animal research in the ways we now look back at those 19th century scientists. \nPsychology as a whole is constantly reflecting on and evolving its ethical practices – current practice is clearly explained in the BPS ethical guidelines Ethical issues are more important to psychological research than most other sciences, because its primary research is on humans themselves, as opposed to electrons, molecules, plants etc. Ethical considerations therefore occupy a prime place with any of the research methods discussed in DSE 212, and you are encouraged to pay careful attention to this aspect with the research you will conduct yourself as part of the course. 

Psychometric (assessment and techniques). Psychometric methods involve measuring psychological characteristics, such as personality, intelligence or aptitudes. Statistical techniques are particularly important, to establish reliability (does the test produce consistent results?) and validity (is the test measuring what it is supposed to be measuring?). Another important concept is 'norms'. For example, on intelligence tests, the norm for children of a particular age is the average score gained by the children of that age on whom the test was standardised. It therefore reflects typical development for that age group. 

Observation is clearly distinguished from experiments by the absence of any intervention. The method is often used in everyday social settings to observe behaviour 'naturalistically', but it is also sometimes used in laboratory settings (though often the reason for the latter setting is for careful control of experimental variables). Data can be both quantitative and qualitative, though most observation tends to involve the latter (see earlier section on qualitative observation under 'qualitative methods'). The data can be structured, and collected in terms of a pre-existing checklist, or unstructured, leaving observers free to write down their overall impressions in any way they see fit. It should be pointed out that even the 'unstructured' approach will still be affected by choices made by the observer to do with selection and construction (see 'construction of data' under 'qualitative methods'). However, 'unstructured observation' is essentially defined as not pre-structured in any way, leaving the observer free to pick up on whatever they think are salient issues, may be missed by more structured data.\nOne particular type of observational method is called participant observation, where a researcher will join in a particular group or social setting, participating in the activities of the group, usually without revealing they are a researcher. Because of its covert nature, this necessarily informal method of data collection raises significant ethical issues. However, it can be the source of very useful data. This approach has a number of factors in common with ethnographic methods (though with the latter, researchers are more likely to be open about what they are engaged in). A key ethical issue in observation in general in fact is that with naturalistic observation the 'participants' are usually unaware that they are being observed. However, if the participants know they are being observed, their behaviour may well change, so destroying the very natural behaviour the researcher wants to observe. This is analogous to the Heisenberg Uncertainty Principle in quantum physics, where bouncing light rays off an electron to find out its location will itself make the electron fly off somewhere else, which means you no longer know where it is! There are no simple answers to such dilemmas: researchers have to take decisions based on the particular research topic and setting they are looking at. 

Introspection. Essentially, this method involves attempting to examine one's own psychological experiences (i.e. the contents and processes of the conscious mind) and report back what is found. This was one of the main methods of the early pioneers of psychology, such as William James, much of whose influential writings of psychology come from relatively informal and unstructured introspectionist reports of his own experiences. In a much more structured and formal way, Wilhelm Wundt established a psychological laboratory in Germany, where he tried to break down sensory experience into its component parts based on introspectionist data from a number of participants. In terms of the history of psychology, Wundt's failure to achieve inter-observer reliability with these types of data led to the rise of Behaviourism with researchers such as Watson rejecting mental data of all kinds as 'unscientific', and limiting psychology to the study of externally-observable behaviour. Since then, introspectionist data have more recently again found a place in psychology (though it's fair to say that introspection is still shunned by many psychological perspectives). In cognitive psychology, although the main focus is usually on experimental data, some cognitive psychologists have got people to 'talk through' their experiences when engaged in cognitive activities such as problem solving, with the resulting 'verbal protocols' seen as a useful complement to experimental data. Introspectionist reports of individual experience are an important part of humanistic and transpersonal psychology (e.g. in studying altered states of consciousness). These type of data are particularly important in transpersonal psychology, partly as a result of the way this perspective has been influenced by eastern philosophies/psychologies such as Buddhism, which have always used introspection as their primary method. 

Clinical observations: case studies. Case studies in clinical medicine involve a detailed account of careful clinical observations, taking the personal history of the patient in relation to the illness, describing the symptoms, diagnosis, treatment(s), and the outcome of the treatments. Within a psychological context, case studies might be relevant to psychotherapy or counselling. Otherwise, they might be drawn from a medical setting, involving psychiatric or neurological observations. The term case study has now been generalised to include very detailed, tightly focused descriptions of single individuals, which might contain both 'inside' and 'outside' data (i.e. the viewpoints of both the researcher and the person being researched). Unlike experiments, which tend to focus on a single moment in time, case studies usually provide a summary over a period of time (cf. longitudinal studies). The main focus is usually qualitative, though some include quantitative aspects. Case studies have proved invaluable in the study of child language development and chimpanzee language. Comparing case studies from a range of different people can provide information about: treatment outcomes, the classification of different clinical disorders, and the basis for developing new theories about particular clinical or social phenomena. 

Qualitative Research. The main focus of qualitative research is on making sense of the meanings of psychological phenomena, rather than the quantitative focus on discovering cause-effect relationships using statistical analyses. In some research qualitative research studies can be combined with quantitative methods. However, many qualitative approaches tend to be critical of the concept of 'objectivity', seeing all research as constructed by the methods, theoretical background and overall viewpoint of the researcher. With these approaches, it is therefore seen as important for researchers to be reflexive about how their experiences impact on their interpretations (to the extent this is possible), and to be transparent in communicating this as part of the reporting of their research results.\nWithin the broad field of qualitative research, there are many different methods, some of which are now described: Collecting accounts. Accounts are collected in different ways, recorded differently and transcribed differently depending on the type and aims of the research. Usually qualitatively based, research involves collecting accounts of people's experiences or behaviour within a certain topic area or focus (e.g. dreaming, experiences of altered states, becoming a mother) and analysing the resulting material, looking for common themes. Discourse analysis. Discourse Analysis argues that language and the way in which it is used play a major role in how we behave and make sense of our social world. Our talk is not seen as a purely private, individual production, but as part of our shared, public and collective realities. Our most fundamental psychological processes, such as our identity, are not seen as something 'intrinsic' but as constructed and negotiated through talk. For example, even the very concept of being a 'unique, autonomous individual' might be seen by Discourse Analysts as a particular construct of Euro-American society, emerging through talk (as compared to the very different conceptions of the self from Japan or India, say). All data are seen as constructions: This methodology falls within the social constructionist tradition (see 'perspectives'). In common with all social constructionist approaches, it rejects the idea that language is a purely 'passive' medium that we use to describe our world. Instead, it argues that language plays a very active role in constructing our world. This construction occurs by way of a number of factors, including: • How we select what is to be discussed (i.e. what is, or is not, seen to be relevant). • The particular way in which what is being discussed is framed – the idea that some ways of making sense of things are 'objectively true', whereas others are 'subjective', is rejected. All are seen as particular constructions of the author, rather than as neutral unbiased 'facts'. One way of making sense of this idea is to imagine yourself making an observation of some interaction. Then imagine observing the same interaction, but through focussing on different aspects (selection), and making sense of them in terms of a different theoretical framework (framing), you could write down a quite different account. For example, the first observation could be made by a psychoanalyst who is primarily looking at how people's body language might reveal internal conflicts and defence mechanisms. The second observation could be made from a researcher interested in the content of the verbal interactions, and how society influences the way people discuss things. Clearly these two observations will produce very different data! Yet both could be argued to be perfectly reasonable ways of observing the situation. So can you say that one is 'right' (and 'objective'), and another is 'wrong', (or 'subjective')? People's accounts are seen as based on their particular ways of making sense of things, and the rhetorical strategies they might use (i.e. the way people will frame their accounts to make them as coherent and convincing as they can). This also applies to psychological research, even discourse analysis itself, which leads to an interesting question: A phrase from the Roman playwright Juvenal's Satires is 'Quis custodiet ipsos custodes?', or 'Who guards the guardians?' In this context, this question can become, 'who analyses the discourse of the discourse analysts'? Discourse analysts have to be sensitive to the way in which their own research is itself a construction, based on particular theories, making use of rhetorical strategies, and so on. For the social constructionist, this is not seen as a weakness, but rather a strength, in that the researcher is encouraged to be reflexive (in trying to be aware, as much as possible, of their own ways of framing things), and transparent –- in communicating this as clearly as possible to the reader when reporting their research results. Social constructionists would, of course, claim that this idea of research as construction is true of all psychological methodologies, criticizing many quantitative/experimental approaches for not acknowledging the extent to which their research is constructed. Social constructionists reject the very concept of 'unbiased, objective' research.\nThe actual methodology of discourse analysis is based on the interpretation of texts, which often make use of transcripts of talk (broadly interpreted to mean pretty much any kind of utterance/conversation/writing). This material is nearly always taken from naturally-occurring talk of some kind (compare this naturalistic focus with laboratory-based research, for example). Material might come from observation of normal everyday encounters between people, interviews, or published material such as newspaper articles. These texts are then analysed to try to reveal the social context from which they emerge. Speakers' accounts of events are seen not simply as passive reports of the 'facts' of what happened, but highly active ways of putting across the way they wish to construct those 'facts'. A good way of making sense of this idea in practise is to look at politicians from rival political parties frantically 'spinning' to get across what may be diametrically opposed ways of making sense of some particular event (e.g. publication of some new statistics on crime or the economy). Rhetorical strategies could be based on trying to show their opponents to be fools and/or knaves, while their own party is the supreme repository of wisdom and skilful policy-making. From this point of view, the 'spin' IS the reality, in that it is people's eventual constructions of an event that tend to have the ultimate impact on a political party's fortunes. Conversation Analysis\nConversation Analysis (CA) has some similarities with discourse analysis, in its even stronger emphasis on using naturally-occurring talk, but tends to focus on highly detailed analysis of smaller samples of language. As its name suggests, CA has a particular focus on how people interact with their talk. The ways in which conversations are socially organised are revealed by a detailed analysis of tape recordings (audio or video) and transcriptions made from such recordings. Although the way we talk with others in conversation may seem very 'natural', CA reveals the ways in which it is based on particular interactional skills. Some of these skills seem to be quite general, others are found more within particular cultures. This method insists on staying very close to the prime data (the tape recordings). However, transcriptions are also used, to show how conversations develop as an interactional sequence. Analysing biography. This approach uses individual biographical details as sources of data. These can then be used to try to make sense of the different psychological aspects of the individual in question. The analysis would often take place from within a particular theoretical context (e.g. Freudian or Jungian psychoanalytic), or might also draw on a combination of theories to help provide insight into different psychological processes. \nInterviewing\nInterviews involve a researcher asking a participant (or informant) for information about a particular research question. This question could be tightly focused, such as 'experience of a particular train journey, or more loosely focussed, such as 'what it means for you to be alive as a human'. The participants would be chosen in terms of their likelihood of having something relevant to say about the research question. \nInterviews can produce both quantitative and qualitative data, and can be structured or unstructured. With structured interviews, there is a detailed checklist of questions to be asked, with little deviation allowed from this. Data are often coded into numbers so that statistical analyses can be done. Unstructured interviews, in their 'pure' form, have no prepared list of questions, in fact nothing apart from an initial focus or topic (e.g. 'experience of motherhood'). From this, the interviewer will try to be very sensitive to what is important to the respondent, in deciding which questions to follow up on or expand. In practise, many interviews lie somewhere between the purely structured and the unstructured format. The interviewer may start off with some prepared topics in an 'interview guide' designed to cover particular themes, but will be quite open to exploring material the respondent comes up with from outside this. This would be called a semi-structured format. (In fact, even 'unstructured' interviews must inevitably involve some choices on the part of the interviewer on what question to ask or topic to follow up at any point). Regardless of format, the resulting data are then analysed to come up with central themes and issues. This analysis looks for the meanings through which people make sense of their lives and experiences. Sometimes, the initial analysis may be offered back to the respondent, for their comments as to how well they think it represents their views. Whether this is done may depend on the theoretical background of the interviewer – humanistic psychologists, for example, place great importance on representing interviewees in terms of the interviewee's own unique worldview. Ethnographic methods\nEthnographic methods originated with anthropology, looking at various aspects of different ethnic groups, or communities in countries other than the anthropologist's own. The focus was frequently culture (meaning everyday practices), history, myths and traditions. This approach makes use of a whole range of methods, based on 'naturalistic' observation techniques, such as recording natural conversations. Often the investigator will themselves become part of the grouping, for periods varying from relatively short time periods up to several years. However, the aim is to participate without altering the situation excessively (it is acknowledged that it is impossible to have no effect at all), in order to discover the viewpoints and activities of the people being observed. This approach has formed the basis for more recent research in social psychology. The basic method, as described above, is that the psychologist participates in the everyday lives of the people being observed, making notes about what is said and the activities that take place. In addition to this 'outside' viewpoint, ethnographers may well also ask individuals to talk about their experiences, providing an 'inside' viewpoint and inner experience data. Another source of data may come from documents or other information sources relevant to the setting being observed. This emphasis on multiple methods is characteristic of ethnography. In the early stages of data collection, ethnographers would try to be as 'unstructured' as possible in their observations, limiting the extent to which their own preconceptions/background influenced what is observed (this cannot be done entirely, but great effort could be made towards trying to be sensitively attuned to the viewpoints and overall worldview of those being observed). This approach will help the central issues involved to start to emerge, through the early stages of analysis. Qualitative observation\nObservation is one of the most basic methods of data collection in psychology. It involves careful attention to some particular aspect of the world. It can take place in the laboratory, during experiments or observations of people interacting or doing particular tasks, or may focus on people engaged in some aspect of their everyday lives, so generating naturalistic data. Examples could be students and teachers in the classroom, people shopping or using a cash machine, mother-child interaction etc. Sometimes video recordings may be made, in other circumstances this may not be possible (or ethical), and data will consist of the observer's own notes of what he or she observed. The essential distinction between an observation and an experiment is that an observation doesn't involve the deliberate manipulation of a particular variable. However, experimental psychologists have to observe the effects of their manipulations and some forms of observation can involve some potential 'interference' with what is being observed. This is particularly true for the method known as participant observation, in which the observer also participates in the activities engaged in by those under observation. The discussion on how all data is seen as constructed in the section on discourse analysis is just as relevant to observational data. 

Philosophical Methods. Philosophy as an academic discipline covers a wide range of topic areas and methods (see perspective on philosophy). However, as a method, one of its key approaches is that of the thought experiment (these are also sometimes referred to by their German name, Gedanken experiment). These involve trying to bring to light some conceptual or logical factor, by constructing an imaginary situation involving some manipulation of the topic under investigation. The logical consequences of this can then be explored. A classic example would be Searle's 'Chinese room', where the scenario constructed involves a person locked in a room, with Chinese ideograms passed through to him. Although he knows no Chinese, he has been given a set of rules telling him what ideograms to pass out, according to the different symbols which are input. Although the outputs may make sense to Chinese people (if the rules are appropriately constructed), the person in the room can't possibly be said to understand the Chinese terms. \nThis thought experiment therefore acts as a way to argue against the concept of 'strong artificial intelligence (AI)', e.g. the claim that if a computer was devised with programs that could talk and speak as effectively as a human, the computer would actually understand what was being said. We can see from this example, how philosophical methods can help us think through conceptual issues arising from psychology. Philosophical tools might also be used, for example, to help analyse the meaning of the term 'understands'. Careful analysis of the meaning of terms is another key tool of philosophy. There is a contrast with methods such as discourse analysis (DA), which is also concerned with analysis of language, but in a different way. DA tries to look at how the language people use acts to socially construct their worlds, and so analyses relatively large chunks of text. Philosophy typically takes a much more technical approach to language, focusing on the meaning of perhaps a single concept, in terms of its logical implications, relationships with other concepts etc. Traditional scholarship\nThis could refer to a number of different things, but in particular would include reviewing the literature to examine the theoretical and empirical contributions of other researchers. These are weighed against each other, looking for mutual support, inconsistencies etc. It might also involve finding new ways of making sense of existing ideas and/or data by synthesizing and integrating what were previously separate concepts/research. 

Longitudinal. Like age-based cross-sectional methods, this approach is designed to provide data on how people change over time. However, it overcomes the methodological problems of cross-sectional studies by making repeated measures on the same group of people over long periods of time. This approach also allows researchers to make detailed observations of major points of change in people's lives (if the times between observations are relatively short). This research would typically take place over a period of some years (or even decades). Although it is a very powerful way of looking at age-related changes, it clearly also involves a great commitment in time on behalf of the researchers (and willingness on the part of their participants to continue participating in the research). Perhaps the best known longitudinal studies are cohort studies that aim to follow people born in one week from birth throughout their lives. 

Experimental (incorporating: Multivariate experimental comparison, Quantitative data collection, Intervention, Quasi-experimental, Cross-sectional) Quantitative data collection Experiments tend to focus on quantitative data, i.e. information in the form of numbers of some kind. It is perfectly possible for qualitative data to be gathered as well, i.e. information in verbal form, though usually in experiments this is seen as of secondary importance compared with quantitative data. Quantitative data do have some disadvantages in that much of the 'richness' of human psychological processes is necessarily lost in reducing it to numerical form. However, there are also many advantages to these forms of data (which is why they have played such a large role in psychological research). Firstly, it can be easier to compare quantitative data from different researchers who are using the same measures, compared with qualitative research, where data can not be 'standardised' in the same manner. Once data are in quantitative form, all sorts of mathematical and statistical manipulations can be employed, giving rise to possibilities that simply don't occur with qualitative research (which does, of course, has its own strengths, as described in the 'methods' section describing these forms of data). For example, average (or mean) scores can be worked out (and perhaps used to compare different groups of people, or between experimental conditions). Statistical tests can be used to calculate whether differences between particular scores are likely to reflect a genuine psychological phenomenon (or are just due to random fluctuations in the data). Other statistical techniques can be used to see if different aspects of data are associated with each other (or 'correlated'). The power of quantitative data can be very easily seen with sciences such as physics, which has given human beings great understanding and control over our natural world. Many psychologists over the past century or so have aspired to placing psychology on the same kind of footing. Experimental Method\nExperiments have been the most commonly used psychological method over the last century of psychological research. It aims to discover if there are 'cause-effect relationships' between variables by changing one variable (the 'independent' variable), and measuring the results of this on another psychological factor (the 'dependent' variable). While doing this, the experimenter will attempt to control all other variables that may affect the results, so that whatever changes occur can be explained in terms of the effect of the independent variable. There is a clear distinction here from observational methods, in that this method is based on a deliberate intervention by the researcher. Experiments can be done in natural settings or in laboratories, though because of the need to control other factors (not easy to do 'in the field'), the majority of experimental research has been done in laboratory settings. ('Laboratory', for a psychologist, often just refers to a room with a computer.) There is something of a trade-off here for a psychologist – the more 'controlled' the setting is, the more certain the psychologist can be that the results are due only to changes in the independent variable and nothing else. However, the very measures taken to reach this careful control can result in an environment unlike 'everyday life'. There is then the question, 'will the results still apply outside the laboratory, in everyday life?' (which is, after all, the usual aim of psychological research). This has been a particularly strong issue for social psychology (e.g. when looking at how people in group come to make decisions), where the socio-cultural setting is clearly going to be a significant component. It is arguably less of a problem with cognitive psychology, where memory research, for example, has benefited from being able to isolate particular memory processes from their everyday contexts. \nWithin the general field of experimental research, there are a number of specialised methods, such as:\nMultivariate experimental comparison. Multivariate approaches are designed to assess the affects of multiple variables simultaneously, instead of just looking at a single variable. This is very important in dealing with complex psychological processes which often have more than one cause. Quasi-experimental, Experiments involve two or more experimental conditions. Ideally, researchers will have full control over who is allocated to the different conditions, e.g. by randomly allocating people to one or other condition. However, with quasi-experimental designs, this control is limited in some way. An example might be research into gender differences, – people are already either men or women, so obviously can't be randomly allocated to the different conditions. Another example might involve looking at people's psychological reactions to experiencing a rail crash (compared with a control group who weren't in the crash). Again, the participants aren't randomly allocated between the conditions. The possibility then arises that there is some other distinction between the groups apart from the chosen independent variable which is giving rise to any differences found in the results. In the second example above, perhaps train travellers in the rail crash are untypical in significant ways from the people in the control group (e.g. if it was a commuter train, there is likely to be an age bias, and possibly also class, gender etc.). One way to try and limit these effects is to use matching – the people in the control group may be chosen to match the people in the 'rail crash' group on age, class, gender and so on. The difficulty is that the researcher can never be certain to have matched all the variables that have an effect. However, for many phenomena (such as the examples above) this method may be the only way possible to study them experimentally. Cross-sectional Studies Cross-sectional research is the most commonly used survey research design. It can provide good descriptions of the characteristics of the groups on whom the research is done and the differences between them. With this method, groups of people are selected from different sections of society. For example, they can come from different age bands. The researchers then compare these different groups (at more or less the same moment in time), looking for developmental trends, or age-related changes. \nThis method is commonly used in developmental psychology, to provide data which can be used to examine developmental theories such as Piaget's theory of cognitive development, or Freud's theory of emotional and personality development. Researchers may also do cross-sectional studies with factors such as social class, gender, ethnicity or occupational group being the basis of the division. One potential disadvantage of cross-sectional studies is that researchers can't be sure two different groups are similar enough for direct comparison. This would mean that there may be other reasons they are different, apart from the one the researcher assumes accounts for the difference. The longitudinal method is designed to overcome this disadvantage. 

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). 

Physiological measurement. This approach takes measurements of human physiology (the structures and functions of the nervous system), to show how our biology affects our behaviour and experience. It can involve measuring the levels of hormones such as adrenalin in the body in order to study their effects (since these effects have been found to be quite context-dependent). Another example might involve measuring of the electrical resistance of the skin, indicating the amount of sweat generated (more technically, Galvanic Skin Response, or GSR) and looking for changes when people are telling the truth or lying. Here a relatively simple physiological measurement is being used as an indicator of underlying mental states.\nAn issue that can arise from use of physiological methods is the question of reductionism, in this context the extent to which complex human behaviour and experience can be explained entirely in biological terms. This is sometimes jokingly referred to as 'nothing-buttery', as in: “the experience of aggression is 'nothing but' the flow of adrenalin and the firing of particular neurons”. The resolution of debates like this require philosophical methods as well as physiological ones. 

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. 

Field research can take a wide variety of forms, but its essential characteristic is that it takes place in peoples' everyday social environments, as opposed to the artificial settings of a psychological laboratory (it is therefore seen as higher in 'ecological validity'). It can take the form of either observations (i.e. with no intervention by the researcher) or experiments (involving an intervention of some kind). Although cognitive psychologists have placed an increasing emphasis on doing research based on 'everyday life', i.e. in the field, field research is particularly valuable for social psychology. Although laboratory research can allow careful control of participants and the experimental setting, the special 'social context' of the laboratory itself can make it difficult to reliably generalize the results to human social behaviour in general. Field research can be qualitative or quantitative, or involve some combination of the two.