RESEARCH METHODS: types of experiments Flashcards
what are laboratory experiments?
Experiment that takes place in highly controlled environments. Researcher manipulates the IV and records the effect on the DV, whilst maintaining strict control of extraneous variables.
This is not always a laboratory - it could be any place where the conditions are well controlled.
Evaluate laboratory experiments.
+ High internal validity - high control over confounding variables and extraneous variables which means the researcher can ensure any effect on the dependable variable is likely to be the result of the manipulation of the IV
+ replication is possible than in other types of experiments because of high level of control. Replication is important to make sure to see whether the finding is valid or not.
- lack of generalisability - lab environment is artificial and is not like everyday life. Participants may behave in unusual ways - this causes low external validity.
- demand characteristics- participants are usually aware that they are being tested in a lab experiment, which may give ‘unnatural’ behaviour.
- low mundane realism - tasks participants are asked to carry put may not be related to everyday life. eg recalling unconnected lists of words.
what are field experiments?
Experiment takes place in a natural setting. The IV is manipulated in a natural, more everyday setting. Researcher goes to the participants’ usual environment rather than how participants go to the lab in a laboratory experiment.
Evaluate field experiments?
+ high mundane realism than lab experiments because environment is more natural. Field experiments may produce behaviour that is more valid and authentic which may be the case if participants do not know they are being studied
- loss of control of CVs and EVs due to the cause- effect of IV and DV being difficult to establish as precise replication is often not possible.
- ethical issues - if participants are unaware they are being studied, they cannot consent to being studied and such research might constitute an invasion of privacy.
What are natural experiments?
The researcher has no control of the IV and cannot change it - someone or something else causes the IV to vary. The IV is natural, not necessarily the setting. DV may also be natural and then studied in a lab.
Evaluate natural experiments.
+ provide opportunities for research that may not be undertaken for practical or ethical reasons. eg studies of institutionalised romanian orphans.
+ high external validity - involves the study of real-world issues and problems. eg effects of natural disaster on stress levels
- naturally occurring events only happen rarely - reducing the opportunities for research.
- participants may not be randomly allocated to experimental conditions - therefore researcher might be less sure whether the IV affected the DV or not.
- research may be conducted in a lab and may lack realism. Demand characteristics may be an issue.
What are quasi experiments?
Quasi experiments have an IV that is based on an existing difference between people. Eg. age, gender etc. This variable hasn’t been manipulated, it simply exists.
what is the difference between a natural and quasi experiment?
In quasi experiments the variable hasn’t been manipulated, it simply exists and in natural experiments the variable cannot be changed.
evaluate quasi experiments.
+ carried out under controlled conditions.
+ replication is possible due to the high levels of control
- cannot randomly allocate participants to conditions and therefore there may be confounding variables.
- IV is not deliberately changed by the researcher, and therefore we cannot claim that the IV has caused any observed change.
what is internal validity?
what is going on inside and experiments
what is external validity?
generalising the findings from a study to other situations such as everyday life.
