Some of you will have heard my talk last November at the Science and Pseudoscience conference explaining why Milgram’s study is not an experiment, even though he called it one. The same issue has arisen with Asch’s classic conformity experiment – oops – study. You can read the lengthy discussion over on psychexchange, but briefly …

In the WJEC AS book we have written (on page 72) Asch’s study is not an experiment and failed to explain why. It is not an experiment because the behaviour being studied (conformity) is not caused by Asch’s manipulation. Some participants conformed whereas others didn’t (a kind of dependent variable). However this difference did not depend on any independent variable – the behaviour of the confederates or the different trials (confederates giving correct answer or erroneous answer). Therefore it is not an experiment, it is a demonstration of conformity or an investigation, if we want to label it. Asch did call it an experiment but people used the term more loosely then.

In his subsequent variations Asch was conducting an experiment e.g. he varied the size of the group which had an effect on whether participants conformed or not (one confederate led to little conformity, 3 led to more). We can therefore conclude that the size of the group causes conformity.

On page 69 (baseline study, paragraph 4) I have called it an experiment! An error.