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Research methods - Coggle Diagram
Research methods
Laboratory experiment
The aim of laboratory experiments is to control all relevant variables except for one key variable, which is altered to see what effect is. The variable that you alter is called the independent variable
Laboratory experiments are conducted in an artificial setting, e.g. Milgram's study
Strengths
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Causal relationships - ideally it's possible to establish whether one variable actually causes change in another
Limitations
Artificial - experiments might not measure real-life behaviour (i.e. they may lack ecological validity)
Demand characteristics - participants may respond according to what they think is being investigated, which can bias the results
Ethics - deception is often used, making informed consent difficult
Natural experiments
This is where the researcher looks at how an independent variable, which isn't manipulated by the researchers, affects a dependent variable.
The independent variable isn't manipulated because it's an event which occurs naturally. An example is research into the effect of a single-sex school and a mixed-sex school on behaviour. Participants are usually allocated to conditions randomly
Strengths
Ethical - it's possible to study variables that it would be unethical to manipulate, e.g. you can compare a community that has a TV with a community that doesn't to see which is more agressive
Demand characteristics - participants might not know they're in a study, so their behaviour is likely to be more natural
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Limitations
Casual relationships - because you don't manipulate the independent variable, and because other variables could be having an effect, it's hard to establish casual relationships
Ethics - deception is often used, making informed consent difficult. Also, confidentiality may be compromised if the community is identifiable
Quasi experiments
In a quasi experiment, the researcher isn't able to use random allocation to put participants in different conditions
This is usually because the independent variable is a particular feature of the participants, such as gender or the existence of a mental disorder
Strengths
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Ecological validity - the research is often less artificial than laboratory studies, so you're more likely to be able to generalise the results to real life
Limitations
Participant allocation - you can't randomly allocate participants to each condition, and so confounding may affect results.
Causal relationships - it can be hard to establish cause and effect because the independent variable isn't being directly manpulated
Field experiments
Field experiments are conducted outside the laboratory. Behaviour is measured in a natural environment like a school, the street or on a train. A key variable is still altered so that its effect can be measure
Strengths
Casual relationships - you can still establish casual relationships manipulating the key variable and measuring its effect, although it's very difficult to do in a field experiment
Ecological validity - field experiments are less artificial than those done in a labratory, so they relate to real life better
Limitations
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Ethics - participants who didn't agree to take part might experience distress and often can't be debriefed. Observation must respect privacy