extraneous variables Flashcards
what does it mean if a study claims to measure what it is measuring
it is valid
what are the three types of extraneous variables
participant variables
investigator effects
situational variables
what are participant variables
extraneous variables that are personal characteristics of the participant
what is the second name for investigator effects
experimenter variables
how do investigator effects occur in a study
when the researcher influences the behaviour of the participants, when then affect the results of the study
how can researchers influence the results of the study
expectations, which is an example of researcher effects
how can the researchers expectations influence the study
this can affect the researchers behaviour. this can then influence the behaviour of the participant, and therefore the results of the study. This is known as investigator effects
what are situational variables
anything external to the participants and researcher that could affect the behaviour of the participants
examples of situational variables
time of day
how noisy the testing room is
what are demand characteristics
situational variables that act as hints that enable participants to guess the aim of the study
what are the two ways that participants can respond to demand characteristics
some participants try to be helpful and behave the way they think they should behave. others rebel and behave the opposite to how they think they should behave
what can demand characteristics be
situational variables or investigator effects
what happens when extraneous variables are not controlled
they reduce the validity and reliability of the study
one way to control extraneous variables
is through standardisation
what is standardisation
when researchers make an extraneous variable the same for all participants, so the validity and reliability increase
why cant you use standardisation for participation variables
because you can’t change a person’s personal characteristics
which extraneous variables can be standardised and why
- investigator effects because we can control factors related to the investigator
- we can standardised situational variables because we can control variables in a situation
what are the limitations of matching
- it can be time-consuming because the researcher has to measure the personal characteristics o their participants then try and identify participants with similar characteristics
- we can’t control for every possible participant variable that could affect the results of the study- some participant variables will not be controlled
what does it mean if a researcher can match their groups for personal characteristics
making sure a particular characteristic of participants is divided equally across groups
what is matching
when researchers allocate their participants to different groups in a way that it makes sure that a particular characteristics is divided equally across both parts
what is random allocation
participants are assigned at random to experimental groups in order to ensure similar participants in each group
what can standardisation be used to control
personal characteristics
what can random allocation be used to control
situational variables
what can matching be used to control
investigator effects
