Memory: Why Do Some Witnesses Misremember What the Suspect Looked Like?

Criminal investigations are initiated after a criminal incident has been reported to the authorities. Arriving officers will therefore seldom have a first-hand (i.e., witnessed) understanding of how the incident transpired and, in many cases, the perpetrators will be long gone by the time the police arrive at the crime scene. Whilst CCTV footage can be acquired in many urban areas, such footage is often limited in quality, context and sound. Resultantly, investigators will often turn to eyewitnesses as an initial source of information to gain some understanding around the incident, with most investigators highlighting that eyewitnesses will usually play a role in solving investigations (Brown et al., 2008). Evidence provided by eyewitnesses can not only be used to help drive investigative enquiries forward but can also be used in a court of law as evidence towards the suspect’s guilt. Witnesses can assist criminal investigations in many ways. Their memory reports can be used to help investigators understand the details to an offence and can later be used as testimonies in court. In cases where the suspect’s identity is unknown, witnesses may also provide a description of the offender’s appearance and be asked to identify the suspected culprit out from a lineup. However, despite the remarkable abilities of human memory to remember distant experiences precisely, evidence from empirical research and case studies show that it is far from infallible. As we will see in the following case study, the assassination of Annah Lindh is just one of many real-world examples that demonstrate the susceptibility of human memory to errors in critical situations. This chapter explores one of the most studied areas of applied psychology, eyewitness memory. More specifically, the chapter considers why some eyewitnesses make crucial mistakes when attempting to identify or describe an offender, focussing on two distinct areas within eyewitness research: unfamiliar face recognition and memory contamination.