Variables and Control of Variables Flashcards
Why do we need to control variables?
If there are other variables other than our IV having an impact on our experiment, we may not be directly measuring our impact on the DV, which will affect the internal validity
What is internal validity?
The degree of confidence that the causal relationship you’re testing isn’t influencing by other factors
What are extraneous variables?
Any factors that could affect the DV
What are confounding variables?
Any factors that affect the DV and systemically change the IV
What are the different types of extraneous variables?
- Demand characteristics
- Investigator effects
- Situational variables
- Participants variables
What are demand characteristics?
Cues that convey the experimental hypothesis to the participants and effects their behaviour
What are investigator effects?
Anything that an investigator does that has an effect on a participant’s performance in a study that what was intended
Describe how you can control demand characteristics
- Single blind design: Participant is unare of which condition they’re in or the research aims, prevents them from seeking clues about aims and reacting to them
- Deception: Lying about the aims of the study
Describe how can you control investigator effects
- Double blind design: When the participant and the person conducting the experiments are unaware of the aims.
- Randomisation: Reducing the researchers influence on the design by leaving it to chance
- Standardisation: The process where procedures are kept the same
Describe situation variables and give examples
- Features of a research situation that influences participant behaviour
- e.g. Order effects, heat and time of day
- Can be controlled through standardisation
Describe participant variables and give examples
- Features of participants that influence their behaviour
- e.g. gender, age, intelligence levels
- Controlled through random allocation (ensuring each participants has an equal change of being assigned to 1 group) or match pairs design
What is validity?
Refers to whether an observed effect is a genuine one
What is internal validity?
The degree to which an observed effect was due to the experimental manipulation
What is external validity?
The degree to which a research can be generalised to other situations
What is ecological validity?
The degree to which a research can be generalised to other settings
