experimental method

• laboratory experiments are experiments that take place in a controlled environment within which the researcher manipulates the IV and records the effect on the DV, whilst maintaining strict control of extraneous variables
• laboratory experiments are conducted in highly controlled environments. this is not always a laboratory as it could be in a classroom where conditions are well controlled. the researcher deliberately changes the independent varaible to see the effect on the dependant variable
• laboratory experiments are conducted in an artificial way
• one strength on lab experiments is that they have high control over extraneous variables. this means that any effect on the dependant variable (DV) is likely to be the result of manipulation of the independent variable (IV). this matters because researchers can be more certain about demonstrating cause and effect so it has a high internal validty
• a limitation of lab experiments is that they lack generalisability. for example, the lab experiments may be artifical and not reflect the activities of everyday life. this means that participants may behave in unusually as this environment in unfamiliar. Also, particpants may know they are being tested in a lab and this may result is more unnatural behaviours known as demand characteristics. this matters because if particpants do not present with their usual behaviours than the research cannot be generalised beyond the research setting meaning lab experiments may have low external validity.
• another strength on laboratory experiments is that replication may be possible. for example, lab experiments are highly controlled by researchers. this means that new extraneous variables are not introduced when repeating an experiment. this matters because replication is vital to confirm that the results on a study are valid
• a field experiment is an experiment that takes place in a natural setting within which the researcher manipulates the independent variable and records the effect on the dependant variable
• in a field experiment the independent variable is manipulated in a natural more everyday setting
• one strength of field experiments is that they have high mundane realism. for example, they are in a more natural environment than lab experiments. this means that field experiments produce behaviour that is more valid and authentic, this is especially the case when particpants may be unaware they are being studied. this matters as field experiments have a high external validity meaning results can be generalised to the wider population
• one limitation of field experiments is that field experiments lack the control that lab experiments have. for example, the increased realism due to the loss of control of extraneous variables may result in cofounding variables. this means a cause and effect relationship between the independent variable and the dependant variable is more diffcult to establish. therefore, precise replication is often not possible
• another limitation of field experiments is that they may have ethical issues. for example, particpants may be unaware they are being studied. this means that particpants are unable to give fully informed consent to being studied. this matters because field experiments may consitute an invasion of privacy
• a natural experiment is when the researcher looks at how an independent variable which isnt manipulated by the researchers, affects a dependant variable. the independent variable isnt manipulated as its an event which occurs naturally. an example would be research into the effect of a single sex school and a mixed school on behaviour as.
• one strength of natural experiments is that they provide opportunities for research which may not be available elsewhere due to ethical issues. for example, Rutter studied institutionalised Romanian orphans. studies similar to this may not be able to be researched upon as the study has variables that would be unethical to manipulate. therefore, natural experiments provide insightful research into areas that otherwise cannot be studied ethically
• another strength of natural experiments is that they have high external validty. for example, researchers can study the effects of a natural disaster on stress levels. this means that research studied is typically on real life issues and problems that have happended. this matters because natural experiments have high ecological validity
• a quasi experiment have an independent variable that is based on an existing difference between people for instance age or gender. no one has manipulated this IV, it simply exists. for instance the anxiety levels of phobic and non phobic patient were compared, the IV of having a phobia would not have come through any experimental manipulation
• one strength of quasi experiments is that they have high external validty. research is based on real effects meaning there is increased realism. this matters because natural experiments have high ecological validity
• one disadvantage of quasi experiments is that participants cannot be randomly allocated to conditions. for example, the conditions have already been allocated as they are pre existing e.g. gender. this means that researchers have no control over confounding variables. this matters because the results may not be valid as there are other variables other than the independent that affects the results
• another disadvantage of quasi experiments is that causal relationships cannot be established. for example, the independent variable is not being directly manipulated. this matters because a cause and effect relationship is not established. this matters because results cannot be generalised to the wider population