Eyewitness memory is a very questionable piece of evidence when presented in court. About 75 percent of DNA-based exonerations have come in cases where witnesses got it wrong. The memory of a witness is easily subject to change and can be altered by a simple suggestion from anyone. The memory of a witness varies depending on the emotions experienced, and the pressure from society to correctly recall and retell the events of the crime. The presence of a weapon also distracts the witness and causes them to pay more attention to the weapon than to the actual perpetrator.