2. Control Of Variables Flashcards
What are Extraneous variables?
Any variable, other than the IV, that MAY have an effect on the DV if it is not controlled. (Does not vary systemically with the IV)
What are confounding variables ?
Any variable, other that the IV, that may have affected the DV so we cannot be SURE of the TRUE sources of change to the DV (does vary systematically with the IV)
What are demand characteristics ?
Any cue from the researcher or from the research situation that may be interpreted by participants as revealing the purpose of the investigation so it may lead to them changing their behaviour
What are investigator effects ?
Any effect of the investigators behaviour which is conscious or unconscious on the research outcome .
What is randomisation?
The use of chance in order to control for the effects of bias when designing materials and deciding the order of conditions
What is standardisation ?
Using exactly the same formalised procedures and instructions for all participants in a study
Name a conscious example of an investigator effect ?
Smiling, shaking head, raised eyebrow, eye contact etc
Name an unconscious investigator effect ?
Age, gender etc
What is the name of the variable that may affect the DV if it is not controlled ?
Extraneous variable
How do you control extraneous variables ?
Identify it at the start of study then take steps to minimise its influence
Name examples of extraneous variables ?
Age, lighting etc.
Name examples of a confounding variable ?
Personality, mood, willingness
What is participant reactivity ?
a phenomenon in which the responses and/or behaviors of study participants are affected by their awareness that they are part of a study
What type of variable is participant reactivity ?
It is an extraneous variable
What is the ‘please-U effect’ ?
When a participant acts in a way that they think is expected and over preform to please the experimenter
What is the ‘screw-U effect’ ?
When a participant deliberately under performs to sabotage the results of the study
What does participant reactivity lead to ?
Investigator effects
What can a researcher do to minimise the effect of extraneous:confounding variables ?
They can use randomisation
What does randomisation prevent ?
It uses chance wherever possible to reduce the researchers influence on the design of the investigation - attempt to control investigator effects
E.g a memory test, what could you do to minimise investigator effects ?
Randomisation, the order of the list of words would be randomly generated so that the position of each word would not be decided by the researcher
What should you do in an investigation with participants who need to participate in multiple conditions ?
The order would need to be completely randomised or you could use counterbalancing
What are standardised instructions ?
Same Instructions that are read to each participant to ensure they know exactly what needs to be done in the study
What can extraneous variables be divided into ?
Situational and participant variables ?
What are situational variables ?
Any features of the experimental situation that may affect the DV
What are participant variables ?
Any individual differences between participants that may affect the DV
Examples of a situational variable ?
Noise, weather, temperature, time of day, instructions
Examples of participant variables
Age, motivation, personality, intelligence, gender, concentration
Explain the difference between extraneous variables and confounding variables
Extraneous variables can be controlled and minimised whereas confounding variables are unexpected and we are unsure of what the true sources changes to the DV are
