True Experiments

Research Methods – Experimental Methodology

In this course, Dr Peter Allen (University of Bristol) explores the experimental structure and methodology that underlies much of the research that informs our psychological theories. In the first lecture, we introduce the gold standard of psychological research: the true experiment. In the second lecture, we break down the term ‘experiment’ by highlighting the definitions of quasi and natural experiments. In the third lecture, we think about the commonly practiced experiment alternative, the observational study – a key aspect of a natural experiment. Next, we build on module three by focusing on the self-report methods which are often used in observational studies. In the fifth lecture, we move to the post-procedure aspect of experimentation by approaching correlations and what they mean in the analysis of results. In the sixth lecture, we bring to light content analysis, a lesser studied qualitative method of categorising and analysing experimental results. In the seventh and final lecture, we think about case studies, the divisive method of study which is in equal part invaluable and useless!

True Experiments

In this lecture, we think about true experiments, focusing in particular on: (i) outlining a number of different ways in which a researcher might investigate how someone responds to music; (ii) three criteria that must be met before considering a relationship to be causal; (iii) two key parameters for manipulating an independent variable when testing for a causal relationship as varying it across multiple levels and randomly allocating each level to each participant; (iv) an example field experiment aimed at improving student learning success, highlighting the important areas of focus to ensure that it is done using the best scientific practices; (v) a comparison between an example field experiment and a laboratory experiment, contrasting the differences and giving examples of how a researcher might perform the same experiment in a laboratory setting.

Glossary:

True Experiment – The purpose of a true experiment in psychology is to explain behaviour by isolating cause and effect relationships between variables.

Causal Relationships – A relationship where change in one variable results directly in change in another.

Field Experiment – A study that is conducted outside of a laboratory, in a 'real-world' setting. Participants are exposed to one of two or more levels of an independent variable being studied, with their reactions observed by an observer(s).