Types of Experiment

• A laboratory experiment is a type of research method in which the researcher can exert high levels of control over what happens as part of the experimental process
• In a lab experiment the researcher controls all possible extraneous variables so that the effects of the independent variable on the dependent variable can be observed and measured
• Lab experiments use a standardised procedures to ensure replicabilty and reliability. All variables kept the same/constant: only the independent variable changes between conditions
• A strength of lab experiments os that it is easier to establish cause-effect relationship between the IV and DV than for the other methods used in psychology.
• A strength of lab experiments is that research is replicable which increases the reliablity.
• A limitation is the use of artificial tasks means that lab experiments lack ecological validity
• A limitation is that in lab experiments there is an increased chance of demand characteristics and that may limit the generalisability of the findings
• A field experiment is a research method which takes place in a natural setting, away from the lab
• Field experiments have less control over what happens as part of the experimental process due to the use of a real-world location. The researcher can control the environment to some extent but they have to acknowledge the fact that many extraneous variables are part of field experiments
• Natural experiments consist of research in naturally occuring phenomena. The researcher cannot randomly allocate participants to condition. Research takes place in natural setting.
• In a natural experiment the researcher observes, measures and records the natural changes and responses which have occured due to the naturally occuring phenomena
• A strength of natural experiments is that they allow the researcher to investigate topics which would otherwise be unethical to study using a traditional lab experiment. So high ethical validity
• Natural experiments have high ecological validity as the participants report on events and experiences that they have personal, first-hand knowledge of.
• A limitation of natural experiments is that causal relationships are difficult to determine due to the array of variables at play. This is a key limitation of research as the researcher cannot be sure as to what effect the phenomena has had on the participants.
• A quasi-experiment is a research method which does not manipulate the independent variable. They are similar to natural experiments as they use naturally occuring phenomena.
• In quasi-experiments the researcher has less control over what happens as part of the experimental process as they cannot randomly allocate participants to condition.
• Quasi experiments collect quantitative data as they can be run in the same way as a true lab experiment. Only variable not controlled in the independent
• Strengths and limitations of quasi experiments are similar to that of natural experiments