research methods Flashcards
What is an Extraneous Variable?
Any variable other than the IV that could potentially affect the DV.
These variables are not the focus of the study but need to be controlled or accounted for.
If not controlled, they can make it difficult to determine the true effect of the IV.
What is a Confounding Variable?
A type of extraneous variable that systematically varies with the IV.
This makes it impossible to tell whether changes in the DV are due to the IV or the confounding variable.
Confounding variables provide an alternative explanation for the results, weakening the study’s internal validity.
What is a Control Variable?
An extraneous variable that the researcher keeps constant across all conditions of the IV.
By controlling these variables, researchers can minimise their potential impact on the DV and increase confidence that any changes are due to the IV.
What are Situational Variables?
Extraneous variables related to the research environment or procedure.
Examples: noise levels, temperature, instructions given, time of day.
Researchers aim to standardise these to ensure all participants experience the same conditions.
What are Participant Variables?
Extraneous variables related to the characteristics of the individuals taking part in the study.
Examples: age, gender, intelligence, personality, prior experience.
Random allocation of participants to conditions can help to distribute these evenly.
What is Internal Validity?
The extent to which a study demonstrates a true cause-and-effect relationship between the IV and DV.
High internal validity means the researcher is confident that the IV caused the change in the DV, and not other factors (confounding variables).
What is External Validity?
The extent to which the findings of a study can be generalised to other:
Populations (population validity).
Settings (ecological validity).
Times (temporal validity).
What is an Independent Groups Design?
Participants are allocated to different groups, and each group experiences one condition of the independent variable (IV).
Data from the different groups is then compared.
Strength: Avoids order effects (practice, fatigue).
Weakness: Participant variables (individual differences between groups) can be a confounding variable.
What is a Repeated Measures Design?
The same participants take part in all conditions of the independent variable (IV).
Data from the same participants across different conditions is then compared.
Strength: Controls for participant variables. Fewer participants needed.
Weakness: Order effects (practice, fatigue, boredom) can affect results. Need to use counterbalancing.
What is a Matched Pairs Design?
Participants are paired together based on key characteristics relevant to the study.
One member of each pair is then allocated to each condition of the IV.
Attempts to combine the benefits of independent and repeated measures.
Strength: Reduces the impact of participant variables compared to independent groups.
Weakness: Time-consuming and difficult to match participants perfectly. If one participant drops out, their pair is lost.
What are Order Effects?
Changes in participant performance due to the order in which they experience the conditions of a repeated measures design.
Practice effect: Performance improves due to familiarity with the task.
Fatigue effect: Performance declines due to tiredness or boredom.
Counterbalancing is used to try and minimise these effects.
