Research Methods Flashcards
Experiments
An investigation that allows researchers to look for a causal relationship; an independent variable is being manipulated and is expected to be responsible for changes in the dependent variable.
Independent Variable
The factor under investigation in an experiment that is manipulated to create two or more conditions (levels) and is expected to be responsible for changes in the dependent variable.
Dependent Variable
The factor under investigation in an experiment that is measured and is expected to change under the influence of the independent variable.
Extraneous/Uncontrolled Variables
Any other variables (besides the IV) that can affect the dependent variable. They can obscure the effects of the IV, making the results difficult to interpret .
Experimental Design
The way in which participants are allocated to levels of the IV (experimental condition).
Independent Measures Design
An experimental design in which a different group of participants is used for each level of the IV (experimental condition).
Control Condition
A level of the IV in an experiment from which the IV itself is absent.
(It is compared to one or more experimental condition)
Demand Characteristics
Features of the experimental condition which gives away the aims. They can cause the participants to try to change their behaviour, for example to match their beliefs about what is supposed to happen, which reduces the validity of the study.
Repeated Measures Design
An experimental design in which all participants perform in every level of the IV (Experimental Condition).
Order Effect
Practice and fatigue effects are the consequences of participating in a study more than once, for example in a repeated measures design.
(They cause changes in performance between conditions that are not due to the IV, so can obscure the effect on the DV)
Practice effect
A situation where participants’ performance improves because they experience the experimental task more than once, for example due to familiarity or learning the task.
Fatigue Effect
A situation where participants’ performance declines because they experience the experimental task more than once, e.g. due to physical tiredness or boredom with the task.
Matched Pairs Design
An experimental design in which participants are arranged into pairs. Each pair is similar in ways that are important to the study and one member of each pair performs in a different level of the IV (experimental condition).
Counterbalancing
A way to overcome order effects in a repeated measures design. Each possible order of levels of the IV is performed by a different sub-group of participants.
(This can be described as an ABBA design, as half the participants do condition A then B, and half do B then A)
Participant/Subject Variable
Individual differences between participants (such as gender, age, personality and intelligence) that could affect their behaviour in a study and hence become extraneous variables.
What are 2 strengths of Independent Measures Design?
- Different participants are used in each level of the IV so there are no order effects.
- Participants see only one level of the IV, reducing the effect of demand characteristics.
What are the 2 weaknesses of Independent measure design?
- More participants are needed than in a repeated measures design so the study can be less effective if there is a small sample because participants are hard to find.
- Participant/Sample variables can distort results if there are important differences between participants in different levels of the IV.
What are 2 strengths of repeated measures?
- Counterbalancing reduces order effects.
- Participant Variables are unlikely to distort the effect of the IV, as each participant performs in all levels.
What are the 2 disadvantages of Repeated Measures Design?
- Order effects could distort the results.
- As participants see the experimental task more than once, they have greater exposure to demand characteristics.
What are the 2 advantages of matched pairs design?
- Participants only see one level of the IV, reducing the effect of demand characteristics.
- Participant Variables are less likely to distort the effect of the IV than in an independent measures design as individual differences are matched.
What are the 2 disadvantages of Repeated Measures Design?
- Availability of matching pairs may be limited, making sample size small.
- The similarity between pairs is limited by the matching process, so the right matching criteria must be chosen in advance for this to be effective.
Laboratory Experiment
A research method where there is an IV, a DV and strict controls. It looks for a causal relationship and is conducted in a setting that is not in the usual environment of the participants.
Reliability
The extent to which a research can replicate its results.
Validity
The extent to which the instruments and methods that are used in the experiment measure exactly what the researcher wants them to measure.
Or
The extent to which the researcher is testing what they claim to be testing.
Pilot Study
A small scale test of the procedure of a study before the main study is conducted. It aims to ensure that the procedure and materials are valid and reliable, so that they can be adapted if not.
