The Experimental Method Flashcards
What is an independent variable?
Different conditions (groups) within the study
What is a dependent variable?
The data collected from the ppts in the study/ what the researcher counts
What is a control group?
A group in an experiment that closely resembles the people under investigation (e.g. does not receive treatment).
Why is a control group used?
So that the researcher can establish if the IV is causing the change in behaviour or if it is down to other factors.
What is the operationalisation of variables?
The precise definition of what is being measured in the research.
What are examples of operationalised variables?
Cold room - temperature e.g. below 8 degrees
Intelligence - score on an IQ test e.g. 120 and above
What is an extraneous variable?
Any variable other than the IV that could affect the DV.
- Controlled so that they do not vary across any of the experimental conditions or between participants
What is a confounding variable?
An extraneous variable that has not been controlled. This occurs when the researcher fails to identify and control for an extraneous variable.
Are extraneous variables controlled or uncontrolled?
Extraneous variables are controlled so that they do not vary across any of the experimental conditions between participants.
Are confounding variables controlled or uncontrolled?
Confounding variables are uncontrolled extraneous variables that may affect the DV and therefore reduce the internal validity of the results.
What are the examples of extraneous and confounding variables?
- Situational variables
- Participant variables
- Demand characteristics
- Investigator effects
What is a situational variable and how can it be controlled
- Aspects of ppt’s environment or the task that might affect their behaviour in the study e.g the lighting or temperature in the room.
- These can be controlled by having carefully standardised experimental procedures and test conditions.
What is a ppt variable and how can it be controlled?
- Characteristics of individual participants (age, sex, intelligence, motivation) that might influence the outcome of a study.
- Can be controlled by through the design of the study (using matched pairs/repeated measures or random allocation if using independent groups)
What is a demand characteristic and how can it be controlled?
- Cues in the environment that the participant can use to work out the aim and hypothesis of the study.
- They can lead to social desirability effects where the participant behaves in a way they think the researcher will want.
- Results will have low internal validity as the researcher is aiming to measure NATURAL BEHAVIOUR
- Can be controlled by using different ppts in each condition or counter balancing.
- Can be controlled by not giving away too much information about the aim and procedure.
What is an investigator effect and how can it be controlled?
- Any unintentional influence of the researcher’s behaviour/ characteristics on participants/data/outcome
- Can be controlled by using more than one researcher checking inter-rater reliability, using double/single blind method or by randomisation
How can investigator effects be minimised in an interview?
- ensure all interviewers are female or male
- ensure students were interviewed by someone of the same gender
- provide a script for the interviewers to use so that they are all asked the same question.
