variables Flashcards
what are variables
things that can be changed or altered such as characterisitics or values. they are generally used in psychology experiments to determine if changes to one thing results to changes in another
what are variables used in correlational studies
covariables
what are covariables
measurements that have been made that are compared to see if they are associated.
how are covariables used in correlational studies
two measured covariables (height and weight) are assessed for a relationship. the direction and strength between covariables can be described.
how can the direction and strength of covariables be described
positive relationship - one co-variable increases so does the other.
negative relationship - one covariable increases, the other decreases
why is the relationship between two covariables not a causal relationship
one doesn’t cause a change in the other
what are the variables in an experimental setup
independant and dependant variables
what are independant variables
the variables the researcher manipulates. these variations in the independant variable form the conditions of an experiment
how do the variations in the IV form the conditions of an experiment
by having a different value of this variable in each experimental condition.
what are dependant variables
the variables the researcher measures
how do researchers claim to have a causal relationship between two variables
their manipulation of the IV causes a change in the measurement of the DV
why do variables have to be operationalised
clearly stating what the variable is and how it is to be measured
what are some examples of operationalised dependant variables
includes the measurement scale
what can happen if other variables that influence the dependant variable aren’t controlled
there won’t be an accurate measurement of the independant variable’s influence on the dependant variable. this could suggest the findings aren’t true as the researcher didn’t set the study up in a way that controls for other explanations in the findings - the study would lack internal validity
what is the difference between internal and external validity
Internal validity refers to the degree of confidence that the causal relationship being tested is trustworthy and not influenced by other factors or variables. External validity refers to the extent to which results from a study can be applied (generalised) to other situations, groups or events.
what needs to be done to test the causal relationship between the IV & DV
controlling confounding variables and minimising the effect of extraneous variables
what are extraneous variables
any variables aside from the IV that could influence the measurement of the dependant variable. this could potentially cause an error and show a causal relationship between the IV & DV that isn’t really there or hiding one
give examples of extraneous variables
demand characteristics
participants variables
situational variables
order effects
what are demand characteristics
if the participant thinks they have discovered the aim they may alter behaviour to match what they think the researcher wants. this could be due to cues from the researcher (such as body language or tone of voice) or the setup that makes the aim obvious
what is the problem with demand characteristics
researcher is measuring the effect of demand characteristics on the dependant variable not the effect of the change in the independant variable
what are participants variables
characteristics like age or gender or cultural background can influence behaviour.
what is the problem with participants variables
in an independant groups design if there are more people with relevant characteristics, prior knowledge or skills related to the task in one condition, this can lead to a difference in performance between conditions unrelated to the IV
what are situational variables
environmental factors present in one condition but not the other condition that could reasonably lead to change in behaviours between the conditions.
give examples of situational variables
this could be related to temperatures, noise or visual differences
what are confounding variables
variables other than the IV that changes systematically between the levels of IV. as you change the IV you will also change the confounding variable.
what is the problem with confounding variables
it hides the IV’s true effect or lack of effect on the dependant variable as the researcher is measuring the confounding variables influence in addition to the IVs.
when do extraneous variables become confounding
if they aren’t controlled before the experiment
how are extraneous variables controlled
actions taken to minimise effect of extraneous variables on the DV
how are participants variables controlled
random allocation
what is random allocation
removes potential bias in assigning more participants with relevant characteristics to one condition in an independant groups design
what is the problem with random allocation
more participants with relevant characteristics can end up in one group due to chance
what is randomisation used for
to assign materials used for different levels of the IV.
give an example of where randomisation would be used
for e.g randomising the individual words into separate word lists for each condition. this is an attempt to stop all the “easy to remember words” appearing in one of the word lists and becoming an extraneous variable.
how is random allocation used in matched pairs design
relevant characteristics are masured before the study adn the top two participants are randomly assigned to separate groups.
how is order effects controlled
counterbalancing
what is counterbalancing
attempts to control (not eliminate). order effects. uses the ABBA format. 1/2 the participants complete condition A then B then the other 1/2 completes this vice versa. this means order effect such as practice and fatigue influence each condition equally.
how are situational variables controlled
standardisation
what is standardisation
only aspects of the environment that could reasonably influence the results are listed in the standardised procedures. this list includes a script of standardisation instructions that is read in the same way to each participants ensuring that each participant has the same experience aside from the variation in the IV.
how are demand characteristics controlled
single/double blind trials
what happens in a single blind trial
the participant doesnt know the aim of the experiment
what happens in a double blind trial
both the participant and the researcher who is directly testing the participant dont know the aim of the experiment
how do single and double blind trials control demand characteristics
this is an attempt to stop the researcher (consciously or unconciously) from influencing the participants behaviour with their body language or tone of voice.
give an example of where standardisation is used
in standardised procedures/scripts
what are pilot studies
a small scale version of the main research study conducted before the main study (using the same methodology)
what is the aim of a pilot study
to improve the quality of the main research study by assessing the experience of the participants in the pilot
give a list of what a pilot study can reveal
- unexpected extraneous variables that need to be controlled
- instructions, tasks or interview questionnaires may be confusing
- participants may reveal they discovered the aim and act according to demand characteristics
- researcher may find that conducting the study is time consuming in its current setup and may need to alter the standardised procedures or tasks
- in an observation it may be clear the behavioural categories aren’t fully operationalised
what is peer review
before publication the researcher needs to show their written up study to other experts in the field. as part of the peer review process, unaccounted for variables may be identified that have confounded the results.
what can peer review show
if the study lacks internal validity and therefore needs to be repeated
what happens with any remaining extraneous variables
researchers try to minimise effects of extraneous variables as much as possible. any remaining extraneous variables are a source of random error but do not invalidate the experiment
