confounding and extraneous variables Flashcards
confounding variable
when the extraneous variables have a confounding effect on variables
3 types of EV
situational, experimenter, participant
situational variables
temp, time of day, testing conditions, venue, background noise
experimenter variables
attractiveness, expectations, health, personality, tiredness, treatment of patients
confound variable eg.
drink red wine often leads to better health
when is reality if you can afford red wine often you can afford a healthy diet and healthcare
what are experimenter effects
the experimenter unconsciously conveys hows the participant should behave through unintentional cues
what demand effects
when participants interpret the experiments purpose, they will ‘try to beat’ it and get a good score
how can i minimise demand effects
deception
what is the hawthorne effect
how humans behave under observation
3 ways to minimise the effects
- random allocation of participants
- sigle blind procedures
- standardisation of procedures and instructions
random allocation
+ ensures each group is identical (IV and C)
- does not guarantee equality of groups, still and element of luck, difficult to implement in the real world
single blind procedures
where the participants doesn’t know if the are in the control group or the experimental group
this does not reduce observer bias, confirmation bias, or bias duo to demand characteristics
it reduces the subject expectation errors
what is a double blind procedure?
where the participants And the experimenter doesn’t know who is in the control group or the experimental group
this reduces observation and confirmation bias
standardisation of procedures and instructions
standardisation means keeping everything the same for all participants so there are no differences eg. writing instructions down so everyone receives the exact same
instructions should be written down or read by the participants themselves to ensure the experiment is fair and the IV is influencing the DV
