ABSTRACT
As an illustration of a formal ‘laboratory’ experiment, a study is described that considers how easy it is to create and detect forged signatures. The nature of signatures in relation to how easy people think a signature is to forge is also considered. Consequently, although this is an intriguing aspect of criminal behaviour it also illustrates aspects of pattern recognition as well the basis of judgements of verisimilitude. How do people identify a genuine signature? Do they focus on small details or form an overall opinion?
This is a controlled experiment. Although it uses actual stimuli generated by people in a context that is close to what would happen in the ‘real world’, it is systematic and carefully managed. It therefore demonstrates the kinds of details that are necessary in any psychological experiment. Many of the features that have to be considered in the constrained context of such a controlled study must be kept in mind. The basis for other studies of the unintentional biases in experiments that can be introduced into many psychological studies are also provided by the example in this chapter.
