Extraneous And Confounding Variables Flashcards
Extraneous variables
Any variable other than the independent variable that if left uncontrolled could effect the dependant variable (measure) (how?)
Confounding variables
If extraneous variable is not controlled they become a confounding variables as they confound (confuse) the results
Participant variables
Any characteristic of the individual participant that could affect the results
Example of participant variables
Age, intelligence, gender, ethnicity, experience, motivation
Investigators will only control relevant extraneous variables
How can participant variables be controlled
Use random allocation = each participant has same chance in one conditions as any other
(Names in a hat, random name generator)
Situational variables
Feature of the research situation that might influence participants behaviour (procedure/methods/resources)
Examples of situational variables
Temperature or noise levels if they affects behaviour being researched
Situational variables - Order effects
Come about when participants are tested more than once (take part in both comditions) - lead to better performance through practice or worse due to boredom or fatigue
Situational variables - investigator effects
Any effects of investigators behaviour on the outcome of the research and also on design decisions
Situational variables - demand characteristics
Refer to anyone from the researcher or research situation that may reveal the aim of the study, and change participant’s behaviour
Situational variables - Standardised procedures or instructions
Overcome investigator effects and demand characteristics
Using exactly the same formalised procedures for all participants ina research study - otherwise differences become EV’s
Situational variables - Randomisation
The use of chance when designing investigations to control the effects of bias e.g. allocation roles to conditions
Situational variables - Counter balancing
Controls impacts/effects of order and effects- doesn’t eliminate
Participants will do both conditions however in another order
Experience IV equally first and second
Order effects are distributed across both conditions
Situational variables - double blind
Controls investigator effects and demand characteristics
Neither participants or nor researcher are aware of studies aims or details - thus have no expectations that will alter participants behaviour
Participants reactivity (effects)
Occurs when participant’s actively seeks cues about how to behave and then responds accordingly
Participants reactivity - examples
Social desirability - people respond in ways that preserve themselves better
The screw/please-u effect - participants attempt to discern the experiments hypothesis and may over-perform or underperform
Participants reactivity - how its controlled
Single blind (can be used to control demand characteristics) - participant not aware of research aims but researcher is (placebo)
