Methods of investigation

Abstract

This chapter looks at the range of methods used by psychologists to obtain evidence about the quality of their theories and the effectiveness of their applications. Knowing about how evidence has been collected is important. One of us recalls watching a nature programme on television and hearing the commentator say that ‘swallows sleep on the wing’. Being in an uncritical frame of mind he found this a fascinating snippet of information and later that evening reported it to some friends. However, in the middle of repeating this snippet, he suddenly thought ‘How do they know?’