Kristjan Kask - What Influences the Eyewitness’s Memory for a Crime?


Sometimes it may happen that we are eyewitnesses to a crime. It means that we have to provide statements about what happened and if necessary, to identify the perpetrator. Associate Professor of General Psychology Kristjan Kask explains why that can be difficult.

Research in legal psychology have found that the accuracy identification of perpetrators depends on several factors such as the luminosity of the crime scene, the distance between the witness and the perpetrator, and the presence of a weapon.

If the perpetrator has a weapon then the eyewitness could less accurately remember his /her face. The scientists have explained this finding in two different ways.

First, the weapon may attract more attention as it is a dangerous object. Thus, we may direct our attention to where the weapon is aiming at. By doing so we try to evaluate the dangerousness of the event – whether the danger remains or has passed?

Second, it can be the effect of novelty. When the eyewitness does not interact with weapons daily then the presence of a weapon during the event can be novel and hold most of the attention. If we have not had any interaction with weapons before then we may face difficulties in both identifying the person and also describing the weapon.

In conclusion, our memory encodes mainly the information where we direct our attention during the event. If the quantity and quality of the information are poor during the encoding, then it affects the accuracy of remembering the event later.

Fact: Our perception is influenced by previous experiences and knowledge