In criminal trials, memory's a basic ... a critical feature of proceedings. Both sides of the legal team - prosecution and defence - are likely to rely to some extent on witnesses and on what they can recall of events that led up to or indeed formed part of the criminal act. Now it's been well established in various circles that memory can be unreliable, particularly if new information is introduced in cross-examination that hasn't been presented up until that point - new facts that witnesses were unaware of. A lot of research has been done to test the effects of this and it can be very problematic. For example, if you show a group of subjects a video of a crime; then you get someone else to read them an account of the same crime, but adding in information, be it ideas or objects, that weren't present on the video. What researchers have found is that when the subjects are asked to re-tell what they saw on the video, they too include a number of things that were never there. In other words, the introduction of new information in a court of law is very likely to skew or distort a witness's memory of the event.