Psychology and criminal investigation
Information is frequently averred to be the lifeblood of an investigation. Psychological science can inform our understanding of the effectiveness of various methods for the elicitation of information from victims, witnesses and suspects that will have a bearing on the quality of the investigation and subsequent criminal justice processes. But a major problem exists in that, as investigators, lawyers and judges often receive no instruction in psychological theory as part of their training, they can remain in ignorance of basic psychological processes involved in the construction of testimony which are often at odds with lay or ‘commonsense’ knowledge (Yarmey 2003: 547). This knowledge gap may have disastrous consequences for their decisionmaking, and it can on occasions contribute to miscarriages of justice (see Chapter 25, this volume). The policy response to miscarriages of justice has been to tighten the legal and regulatory framework governing investigative interviewing and, in particular, the custodial questioning of suspects. More progress needs to be made in promoting a better understanding of psychological processes which would lead to more effective investigations and safer criminal justice. A trend can also be observed of the application of behavioural science to investigations.