Critically Evaluate the Experimental Methods of Research in Psychology

The first method of research is laboratory experiments. These are used because they give the researcher more control over the experiment. This is the most scientific method of research because the researcher is able to deliberately manipulate the IV whilst controlling the confounding variables, making the outcome of the experiment, the DV, more accurate. The manipulation of the IV indicates a cause and effect relationship between the IV and the DV. The controlled conditions of the laboratory environment make it easy for the experiment to be replicated if further research is required. Also, technical equipment can be used to make the experiment more accurate. Another advantage of this method is that it can be easily structured to provide quantitative data. This would be more difficult in a natural environment as the researcher would have very little control over confounding variables. However, laboratory experiments do not provide total control over all variables. Another disadvantage is that the conditions of the laboratory are artificial and lack ecological validity i.e. they do not generalise to the characteristics of a real-life situation. Demand characteristics are also a problem. This is when the participants are aware that they are taking part in an experiment and therefore act in the way they think the researcher would want them to act. They may be deliberately trying to go against the researcher’s aims or they may see their behaviour as helpful to the researcher. This relates to the social desirability effect, where the participant may behave differently to how they would in a natural environment because they want to give what they believe to be a good impression. Another problem is the experimenter effects. This is when the researcher may act or behave in a particular way that may influence the behaviour of the participants.  

The second method of research is field experiments. These are studies which take place in natural conditions, but where the criteria for an experiment are met. The researcher deliberately manipulates the independent variable in its own natural environment. The advantages of field experiments are that they have a higher ecological validity than laboratory experiments because they are constructed in natural environments. It is also less bias from demand characteristics. However it is more bias from confounding variables as it is harder to control all areas of the experiment. It is also more difficult to replicate the experiments exactly and to record data accurately. There are also problems because the researcher is not asking the participants for their consent and could be invading their privacy. The experiment would therefore be unethical.

The third method of research is natural experiments. In these experiments the independent variable is changed by natural occurrence. Natural experiments have high ecological validity as ‘natural’ changes occur in natural environments. There is also very little bias from demand characteristics. However, there is no direct manipulation of the independent variable and the researcher has very little control over confounding variables which makes it virtually impossible to replicate an experiment exactly. It is also unethical because the researcher will not have the participants consent as they are unaware that they are being studied.