Experiments Flashcards
Strengths of Lab experiment (method)
High level of control over extraneous variables e.g. light as its carried out in a fake environment (CONTEXT), therefore cause and effect can be established between the IV and the DV which increases the internal validity of the research.
High in reliability as the experiment (CONTEXT) can be easily repeated in the same conditions to check for consistent results
Limitations of Lab experiment (method)
Lacks Ecological validity as it’s carried out in an artificial environment (CONTEXT) therefore it is difficult to generalise the findings (CONTEXT) beyond the setting of the study, lowering the external validity.
Is prone to demand characteristics, where the Ppt’s change their natural behaviour based on clues given off by the researcher (CONTEXT) this could lead to ppts choosing to either help or hinder the researcher, reducing the internal validity.
Strengths of Field experiment (method)
Less prone to demand characteristics as people might not know they are being watched so they are less likely to guess clues given off by the researcher and change their natural behaviour (CONTEXT). Therefore increasing the internal validity.
High ecological validity as it is based in a real life setting therefore it is easier to generalise the findings beyond the setting of the study to other similar settings (CONTEXT) increasing the external validity.
Limitations of Field experiment (method)
Low in reliability as the environment is natural (CONTEXT), it is difficult to repeat with exactly the same conditions to check for consistent results.
This could create an ethical issue of lack of informed consent as people may not be aware they are being studied (CONTEXT), so wouldn’t have given their consent. If they become aware they may become upset and wish to withdraw their data from the research.
Strengths of Natural experiment (method)
Natural experiments provide opportunities for research that may not otherwise be undertaken for practical or ethical reasons. For example, Rutter’s study on Romanian orphans would have been unethical to manipulate unless the institutionalisation (IV) had not occurred naturally (CONTEXT). Therefore, natural experiments contribute to a greater psychological understanding of behaviour.
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High ecological validity as natural experiments are often based in a real life setting, therefore, it is easier to generalise the findings beyond the setting of the study to other similar settings (CONTEXT) increasing the external validity.
Limitations of Natural experiments (method)
Naturally occurring event may only happen very rarely which limits opportunities for research (CONTEXT) this means it is unlikely that the research can be repeated to check for consistent results so lacks reliability.
Low control over extraneous variables as natural experiments usually take place in a natural environment (CONTEXT). Therefore it is difficult to establish cause and effect between the IV and the DV lowering the internal validity of the study.
Strength of Quasi experiment (method)
REMEMBER – QUASI CAN BE CONDUCTED IN A NATURAL OR CONTROLLED ENVIRONMENT (Field or Lab). THEREFORE, DEPENDING ON THE SCENARIO, YOU WOULD HAVE TO SELECT THE APPROPRIATE EVALUATION (STRENGTHS AND WEAKNESSES).
Strength of Quasi experiment (method)
REMEMBER – QUASI CAN BE CONDUCTED IN A NATURAL OR CONTROLLED ENVIRONMENT (Field or Lab). THEREFORE, DEPENDING ON THE SCENARIO, YOU WOULD HAVE TO SELECT THE APPROPRIATE EVALUATION (STRENGTHS AND WEAKNESSES).
Limitation of Quasi experiment (method)
Sample bias as the sample being studied may have unique characteristics (E.G), which may mean that it is difficult to generalise to the target population (CONTEXT) decreasing the external validity of the study.
Advantages of independent groups (experimental design)
There will be no order effects as ppts only take part in one condition so they will not get bored/fatigued or better at the task/have lasting effects from one condition to the next (CONTEXT) UNLIKE repeated measures design where ppts take part in all conditions and could have order effects.
Can be used when repeated measures design is inappropriate (e.g. quasi experiments when looking at gender differences) (CONTEXT) as each condition needs different Ppts.
Disadvantages of independent groups (experimental methods)
Individual differences may affect the DV as there are separate groups of Ppts in each condition e.g. some Ppts could have a better memory which wouldn’t be suitable in a memory study (CONTEXT) lowering the internal validity, UNLIKE repeated measures that uses the same group of individuals in all conditions to reduce the effect of individual differences.
More Ppts are needed as two different groups are required for the different conditions (CONTEXT) UNLIKE repeated measures where you use less ppts as every ppt takes part in all conditions.
Advantages of repeated measures (experimental design)
Individual differences between participants in each condition are removed e.g. IQ as potential confounding variables, as the same Ppts take part in all conditions (CONTEXT). Therefore, the researcher can be more sure that any changes in the DV are due to the IV and not any other variable increasing the internal validity of the research UNLIKE IGD that will use different ppts in different conditions so individual differences could affect the DV.
Requires fewer participants as the same Ppts take part in all conditions (CONTEXT) UNLIKE in an independent measures design as separate groups are needed for separate conditions.
Disadvantages of repeated measures (experimental design)
P)Order effects may occur
E)when participants take part in more than one experimental condition they may perform worse in the second condition (due to boredom or fatigue) or better in the second condition (due to practice), or there may be lasting effects from condition 1 to condtion 2 (CONTEXT) lowering the internal validity
E)UNLIKE independent measures where ppts only take part in one condition so cannot be susceptible to order effects.
P)Increased chances of demand characteristics as participants take part in all conditions.
E) They may pick up on clues given off by the researcher as they spend much more time with them, or from the research situation , and change their natural behaviour to help or hinder the research (CONTEXT) lowering the internal validity, E)UNLIKE IGD where ppts are less likely to pick up on clues as the only take part in one condition of the research
Advantages of matched pairs (experimental design)
Reduces individual differences between participants as it matches ppts on variables important to the reserach, such as IQ/age/happiness. (CONTEXT) Therefore, the researcher can be more sure that any changes in the DV are due to the IV and not any other variable. UNLIKE in an independent measures where separate ppts are in separate conditions.
There will be no order effects as ppts only take part in one condition so they will not get bored/fatigued or better at the task/have lasting effects from one condition to the next (CONTEXT) UNLIKE repeated measures design where ppts take part in all conditions and could have order effects.
Disadvantages of matched pairs (experimental design)
Very time consuming to match up and find similar participants. (CONTEXT) especially if a pre-test is needed to match ppt on a certain characteristic. The psychologists would need a very large pool of people UNLIKE repeated measures design where you use the same ppts in all conditions.
Individual differences cannot be fully eliminated. Psychologists match ppts on variables important for the research but are not able to match ppts on all variables (CONTEXT). Therefore this could question the validity of the matched-pairs design. UNLIKE RM where each condition will use the same ppts therefore, indivudal differences will be eliminated.
