Research methods: experimental Flashcards
IV definition
variable that is manipulated by the researcher to see if it has an effect on the DV
DV. definition
variable that is measured to see the effect of the IV
operationalising definition
to be clear and specific when defining the IV and DV to make it easier to measure
what is the aim of research
-general statement of what the researcher intends to investigate
-purpose of the study
what is the hypothesis of the research
specific, testable statement in which the researcher predicts what will happen between the variables
directional hypothesis definition
the researcher predicts the direction that the results will go in
another name for a directional hypotheses
one tailed hypothesis
writing frame of a directional hypothesis
There will be a significantly higher/faster/more (operationalised DV) when participants (one condition of IV) compared to when participants (other condition of the IV)
null hypothesis definition
- IV has no effect on the DV
-results were due to chance
null hypothesis writing frame
there will be no significant difference in (operationalised DV) when (operationalised IV) compared to (operationalised IV)
Extraneous variable definition
-unwanted extra variables other than the IV that could have had an effect on the DV
-lowers the internal validity of the study
confounding variables definition
when an extraneous variable is not controlled for and it does affect the DV
lab method AO1
-highly controlled environment
researcher manipulates the IV
-to see the effect on the DV
lab methods strengths
High level of control over extraneous variables 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 can be easily repeated in the same conditions to check for consistent results.
lab methods limitations
Lacks Ecological validity as it’s carried out in an artificial environment therefore it is difficult to generalise the findings beyond the setting of the study, lowering the external validity.
Can encourage demand characteristics, where the Ppt’s change their natural behaviour based on clues given off by the researcher this could lead to ppts choosing to either help/hinder the researcher, reducing the internal validity.
field method AO1
natural environment
researcher manipulates the IV and records the effect on DV
field method strength
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 in order to help/hinder the research 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 increasing the external validity.
field method weakness
Low in reliability as the environment is real so 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 on so wouldn’t have given their consent. If they become aware they may become upset and wish to withdraw their data from the research.
natural method AO1
-naturally occurring IV
-changed even if the experimenter not interested
-could happen in a lab or a field
natural method strength
Natural experiments provide opportunities for research that may not otherwise be undertaken for practical/ethical reasons. For example, Rutter’s study on Romanian orphans would have been unethical to manipulate unless the institutionalisation (IV) had not occurred naturally. Therefore, natural experiments contribute to a greater psychological understanding of behaviour.
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 increasing the external validity.
natural method limitations
Naturally occurring event may only happen very rarely which limits opportunities for research, unlike lab experiments where IVs can be manipulated by the researcher any time. Suggesting other types of experiment may be more convenient for research than natural experiments.
Low control over extraneous variables as natural experiments usually take place in a natural environment. Therefore it is difficult to establish cause and effect between the IV and the DV lowering the internal validity of the study.
quasi method AO1
-existing difference between people
-which the researcher has not manipulated
-records the effect on DV
eg. age or gender
quasi method strength
quasi method strength
quasi method limitations
Sample bias as the sample being studied may have unique characteristics, which may mean that it is difficult to generalise to the target population decreasing the external validity of the study.
independent groups design AO1
ppts take part in one condition only
each condition has different groups of ppts
independent groups strength
There will be no order effects as ppts only take part in one condition so they will not get bored/fatigued/better at the task or have lasting effects from one condition to the next 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) as each condition needs different ppts
independent groups limitations
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 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 UNLIKE repeated measures where you use less ppts as every ppt takes part in all conditions.
repeated measures AO1
all ppts take part in all conditions of the experiment
repeated measured strength
Individual differences between participants in each condition are removed as the same ppts take part in all conditions.Therefore the researcher can be sure any effect to the DV is sue to the IV and not any confounding variables increasing the internal validity of the research UNLIKE IGD 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 UNLIKE in an independent measures design as separate groups are needed for separate conditions.
repeated measures limitation
Order effects may occur when participants take part in more than one experimental condition they may perform worse/better in the second condition due to bored/fatigue/better in the second condition (due to practice), or there may be lasting effects from condition 1 to condition 2 lowering the internal validity UNLIKE independent measures where ppts only take part in one condition so cannot be susceptible to order effects
Increased chances of demand characteristics as participants take part in all conditions. 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. Lowering the internal validity UNLIKE IGD where ppts are less likely to pick up on clues as the only take part in one condition of the research
Matched pairs AO1
-ppts are matched on important characteristics in the study
-given them an appropriate test and match two ppts on same score
-each member is randomly allocated across each condition