Research is defined as by the Oxford Concise dictionary as the investigation into materials and sources as well as the study of these. Tuckman (1978) defines research as a systematic means of problem solving. Research forms an important part of psychology that every psychologist will have to make use of. In this essay, various methods of research will be explained by exploring the different types, the advantages and disadvantages as well as the importance of each for psychology research. Research methods can either be experimental or non-experimental. The experimental method is most well known and used and will be the focus of this essay. There are five main aims of research, which include establishing facts, reaching new conclusions, discovering new facts, collating old facts and problem solving. The ways in which these aims are achieved, which are also known as research methods include the following; systematic investigation, the study of sources, scientific study of certain pieces and critical investigation. It is important to note that all research is required to be systematic, or done according to a specific plan.There are three different types of experiments in experimental research methods, namely laboratory or controlled experiments, field experiments and natural experiments. Laboratory experiments occur in controlled environments, giving the researcher the power to decide where, when, with who and under what circumstances the experiment will take place, using a standardised procedure. A well known example of this form of research would be Milgram’s experiment on obedience, which took place in 1963. The ethicality of this experiment is questionable, however. This type of experiment is simple to duplicate because standardised procedures are used. There is also a high level of control over the variables with these types of experiments, which allows for the cause and effect to be determined easily. However, the artificial settings are criticisable as they could affect the ecological validity in the experiment. There could also be chance for bias throughout the experiments, which is another criticisable characteristic. Field experiments make use of everyday environments, but the experimenter will still alter the independent variables. A good example of a field experiment is Hofling’s hospital study of obedience (1966), which produced a more practical and realistic study of obedience compared to Milgram’s. Field experiments are seen to have more ecological validity as opposed to laboratory experiments simply because the behaviour seen will be more similar to that of real life behaviour thanks to the natural setting. Although there is less control over the extraneous variables, which could lead to the results being biased. Natural experiments occur in everyday environments without any interference from the experimenter. A good example of this type is Hodges and Tizard’s attachment research (1989), which compared the long term development in children who were adopted, fostered or returned to their mothers with children who spent their whole lives with biological mothers and fathers. Natural experiments have the highest ecological validity because of the natural settings, however these kinds of experiments could be more costly and time consuming. Collis and Hussey (2009) classified the types of research according to the purpose of the research, the process and the outcome of the research. These can all be further classified as follows; the purpose can either be descriptive or predictive, the process can either be quantitative or qualitative and the outcome can either be basic or applied. These classifications help psychologists to determine the best research method for specific research that is carried out. It is clear that research forms an important part of any psychologist’s work and that the different types of experiments will lead to different results. It is also clear that psychology researchers should know which method to use to maximise their results.