I assume that you came from the Simple Variables section. In truth, there isn’t that much more that you need to know about variables now.
However… I didn’t say you had learnt it all.
These are variables that come from outside of the experiment enviroment that may have influenced the results. The best way to remember an EXTraneous variable, I think, is to think about it being an EXTernal variable. Clever, huh?
An example of an extraneous variable is the noise level in a field experiment affecting the concentration level. If this is not the independent variable then it must be an extraneous variable.
Extraneous variables should be controlled to the best ability of the researcher so that they do not become Confounding variables.
This is an extraneous variable that influenced the results.
The best example I can think of is if a seagull was to fly in a window during a concentration experiment. That is bound to influence the results.
These are variables that relate to the place, or situation, in which the experiment is conducted.
An example of this is the temperature of the room in which an experiment is carried out. If it is too hot or too cold then the results will be interfered with.
These are controlled by ensuring the conditions are the same whenever they can be. This often a problem in field experiments as they have low levels of control.
These can also be extraneous variables but are better off called Situational Variables.
These are what makes you… you. It is how clever you are, whether you are thin or… less so.
These are important if you are doing matched pairs design so you can match up people with someone of similar IQ.
You might think that seems like a lot but really that’s all trimmed down. The more complex variables are known as:
These are things in the environment that might help the subject work out what the research hypothesis is. These are avoided because if they know they hypothesis then they may adjust their behaviour accordingly.
Example: If you work out you are being judged on your confidence levels then you will increase them accordingly.
A researcher may adjust their behaviour in such a way that it influences the behaviour of the participants. This is done unconsciously so even the researcher would not know they are doing it.
You only need to know about these 2 methods that are used to reduce the amount of demand characteristics:
Single Blind Technique:
This is used to ensure that the pariticpant does not know about the hypothesis so can no change their behaviour accordingly.
Double Blind Technique:
This is when the Researcher and the participants do not know what the research hypothesis is so cannot change their behaviour accordingly. This is usually done with a research assistant as it is impossible for the person who created the hypothesis to do it because he knows what the hypothesis is… after all, he created it.