Research Methods : Research Issues : EXTRANEOUS VARIABLES! Flashcards
What are the three types of research issues
extraneous variables
confounding variables
demand characteristics
What is the key to any experiment
changing IV to see how this affects DV
What is the only thing that should influence the dependent variable
IV
Any variables that may interfere with IV (or DV) should be
controlled or removed
Define extraneous variables
nuisance variables that vary systematically with the iv
variable other than IV
that may affect DV
if not controlled
If possible when are EV identified
At the start of the study
EV are identified at the start of then study by who
the researcher
EV are identified at the start of the study by researchers who do what
take steps to minimise their influence
True or false most Extraneous variables are straightforward to control
true
Give an example of EV that are easy to control
age of the particpants
lighting in the lab
EV are described as nuisance variables that do not …
done delete
EV/nuisance variables may do what to the experminetal water
muddy it
EV/Nuisance variables muddy the experimental water but do not what
confound the findings of the study
Overall EV/nuisance variables make it harder to
detect a result
what does control mean
actions taken to minimise effect of Extraneous variables on the dv
demand charactersitics are a type of
extraneous variable
define participant variables ( a type of extraneous variable )
in an independent group design , if there are more people with
relevant charcteristicss, prior knowledge or skills related tot the task in one condition
this can result in a difference in performance between conditions unrelated to the IV
What are situational variables
enviro factors present in one condition but not otehr that could reasonablty lead to a change in behaviour between conditions
e.g temperature , noise, visual differences
what are order effects
in a repeated measures design the fact that the participant has already completed one condition can alter behaviour in teh second condition
e.g performance improvement due to practice
perfomance decreases due to fatigue
how can i reduce impact of particpant variables
random allocation
randomisation
random allocation removes
potential bias
how does radom allcoation remove potential bias
assings more pt with relevant characteristics to one condition in an independent group design
but more pt with relevat characteristics can end up in one group due to chance
randomisation is one way to reduce ev t/f
t
explain how matched pairs works/ reduces participant variables
relevant characterisitics are measured before the study and top 2 pt are randomly assigned to seperate groups
how can we control order effects
counterbalancing
explain counterbalancing/how it helps
abba format
half pt complete condition a first then b
other half of pt complete b first then a
meaning order effects such as practice influence each condition equally
how can we reduce situational variables
standardisation
how does standardisation work
allows researchers to ensure each pt has same experience apart from variation in iv
how can we reduce demand charcateristics
single and double blind trials
in the single blind trial the pt doesnt knwo
the aim of the experiment
in a double blind trial both the pt and researcher dont knwo
aim of the experimetn
double blind trials attempt to stop researcher from
conciously/unconsciously influencing pt behaviour with their body language/tone of voice
what else reduces the lieklihood of demand characteristics
standardised procedures/scripts
