Some methods used in psychological research

Abstract

The term experiment is frequently used (often wrongly) to refer to a wide range of research procedures. It is necessary at an early stage to make quite clear what the term relates to. In an experiment, the researcher deliberately isolates and manipulates one variable (referred to as the independent variable [IV]) in order to observe and measure the effect of this manipulation upon another variable (the dependent variable [DV]). There will almost inevitably be other factors which will interfere to cloud the link between IV and DV. These are referred to as extraneous variables and they must be carefully controlled by the experimenter. An example set out in Box 34.1 will make this clearer.