If you did your independent groups
experiment at different times of the
day (morning & afternoon) it may
change the DV. This means the time
of day is the confounding the
Experimenters may claim the IV caused the DV to change but this may be caused by the CV.
Consequently, experimenter may
not have tested what they wanted
Influence of different variable has been tested instead.
Experimenter must be careful to control any possible CVs (e.g test at same time of day).
Extraneous Variables (EV)
Some participants may have better memories than others.
It is more likely that this variation is a nuisance
variable because we can never be sure that people
with good or bad memories (in this e.g.) are likely
to be distributed evenly across the two conditions.
These nuisance variables are EVs because they may
affect the DV but not in a systematic way.
Should be controlled as much as possible.
e.g. controlling noise distractions
More difficult to detect an effect
because other factors have an influence.
The point of realism is to be able to generalise the results beyond the particular unique research setting.
If the materials used in the study
are contrived e.g. film clips, then
behaviour observed may lack
Even if the environment and materials are 'natural' or
real (high realism), a study can lack generalisability.
e.g. if participants in a study are American uni students, it may
not be reasonable to generalise the findings to the behaviour of
all people because Americans (and students) may have unique
characteristics that may set them apart from others.
If the environment of the study is contrived and
esp. if participants know they are being studied,
their behaviour may lack realism.
Psychologists always ask
themselves: "To what extent can
I generalise these findings to
Aim of any psychological study is to provide info about how people behave in 'real life'.
If the set-up of a study is too artificial or contrived,
participants won't act as they will normally.
Many things affect the realism of a psychological study.
'mundane' - of the world (commonplace, ordinary)
Lack of it means something is not like everyday experience.
ADD PICTURE FROM PG 113 OF TEXTBOOK
Refers to how true or legitimate something is as an explanation of behvaiour.
Often assumed that validity is about 'being correct'. This is both right and wrong.
Right - a researcher seeks to find out
whether their hypothesis is
Wrong - ...if you think that being
correct means finding out that the
predicted expectations have been
Validity is not about confirming your expectations.