Please enable JavaScript.
Coggle requires JavaScript to display documents.
CONTROLLING VARIABLES - Coggle Diagram
CONTROLLING VARIABLES
Types of extraneous variables
Experiment:
the effects of music (rock and classical) on concentration (time to complete a word search). All participants will do both conditions (repeated measures)
Order effects:
e.g. learning, boredom
Situational variables:
time of day, the environment: heat/noise/distractions
Investigator effects:
behaviour of the investigator may affect participants behaviour, Body language or tone of voice alters their response and result in demand characteristics
Controlling extraneous variables
Order effects:
counterbalancing or independent groups design where each participant only does 1 condition
Participant variables:
random allocation, repeated measures, matched pairs
Situational variables:
standardised procedures/instructions
Investigator effects:
double blind design (participant and experiment do not know the aims of the experiment
Give an example of a cofounding variable in the context of a named study
In Harlow's (1959) study of attachment, the cloth covered and wire surrogate mothers had different heads. the different heads acted as cofounding variable, because they varied systematically with the independent variable (i.e. the 'mother' being cloth - covered or not
Why is it important to control extraneous variables in a study?
It is important to control extraneous variables because they are 'nuisance' variables that affect the dependent variable, but not in a systematic way
Distinguish the difference between extraneous variables and confounding variables
An extraneous variable does not vary systematically with the independent variable. it does not act as an alternative independent variable, but may have an effect on the dependent variable. A confounding variable does vary systematically with the independent variable. It therefore can act as an alternative variable that affects the dependent variable
Explain what is meant by investigator effects. Use an example in your answer
An investigator effect is anything that an investigator does that has an effect on a participant’s performance in a study, other than what was intended. An example is when an experimenter unconsciously encourages some participants by being more positive with them than with other participants.
Explain how a researcher might deal with the effects of demand characteristics
One way to deal with demand characteristics is to use a single blind design. In this, participants are not aware of the research aims and/or which condition of the experiment they are receiving. This prevents them from seeking cues about the aims or reacting to them.
Explain what is meant by demand characteristic
A demand characteristic is a cue that makes participants unconsciously aware of the aims of a study or helps participants work out what the researcher expects to find