Basic steps in building a cognitive psychology experiment

In this video Rob lays out some basic considerations that should be borne in mind when we intend to develop an experimental test of a question about how the mind works.

So there are things that we change and things that we measure and we must try and make sure that the thing that we are changing is responsible for the changes in what we are measuring. As experimental psychologists, we must be on the constant look out for other things that might be changing as we test our participants: Such things are sometimes called uncontrolled variables – things that change that we have no control over.

Most of the time we may be able to ignore these on the assumption that these are changing randomly over time. However, we must be particularly aware of any possible uncontrolled variables that are confounded with the thing we are changing – these are things that vary consistently with the thing we are varying and these are known as confounding variables. The problem now is that if you have two things that are varying consistently with one another then you do not know which is responsible for the changes in the thing you are measuring.

You need to consider what a possible confounding variable is in the experiment Rob has discussed.