Experimental Methods Flashcards
What are experimental methods?
They are an attempt to find a cause and effect relationship between an independent variable and a dependent variable.
What are the 4 different types of experiments?
- Laboratory experiments
- Field experiments
- Natural experiments
- Quasi experiments
Explain and evaluate laboratory experiments.
Laboratory experiments:
- They are conducted under high levels of control that the researcher has over all the variables in the study
- The researcher manipulates the independent variable to measure the effect it has on the dependent variable.
- Participants will be aware that they are taking part in a study due to the nature of the situation which may feel unlike real-life.
Evaluation:
- Lab experiments are highly controlled and contain standardised procedures which means it is easy to replicate the study by other researchers.
- Lab experiments can lack external validity because the artificial nature of the environment means that the study can lack ecological validity. This means the findings of the study cannot always be generalised outside the settings of the lab since the lab tasks often lack mundane realism and are not everyday life occurrences. Participants are also aware of the study and their behaviour could change it to better adapt the task.
Explain and evaluate field experiments.
Field experiments:
- They are carried out in natural conditions where the researcher manipulates the IV to measure the effect on the dependent variable.
- The ‘field’ is any location outside the lab e.g. shopping centre.
- Participants are not aware that they are taking part in a study and therefore researchers are able to observe more natural behaviours
Evaluation:
- The natural setting means that field experiments have a higher ecological validity than lab experiments which means the findings are much more likely to be generalised as everyday behaviour.
- There are ethical issues within field experiments. Since the participants are unaware of the study taking place, they cannot consent to being a part of it.
Explain and evaluate natural experiments
Natural experiments:
- In natural experiments, the researcher does not manipulate the independent variable. Instead it examines the effect of an existing independent variable on the dependent variable.
- The independent variable is naturally occurring e.g. flood or earthquake. The behaviour of the people affected are either compared to their own behaviour beforehand or with a control group who have not encountered the independent variable.
Evaluation:
- A naturally occurring event may happen rarely hence it is difficult to generalise results to other circumstances.
- Natural experiments have a high level of external validity because real life issues are being studied rather than manipulated artificially.
Explain and evaluate quasi experiments.
Quasi experiments examine the effect of a naturally occurring independent variable (that already exists) on the dependent variable. The independent variable is a difference between people such as gender or age. Quasi experiments usually take place in natural settings but can also take place in a laboratory setting.
Evaluation:
- One limitation of quasi experiments is that if they occur in a natural setting, there is no control over the environment and extraneous variables which makes it difficult to tell whether factors such as age or gender have influenced the dependent variable. On the other hand, when quasi experiments take place under laboratory conditions, the high level of control means that the research often lacks ecological validity and the results often cannot be generalised to a real-life setting.
