If eyewitness memories are missing, the brain makes them up, and scanning technology has a hard time telling real from fake.
Sitting in her office at Claremont Graduate University in California, cognitive psychologist Kathy Pezdek flips open a case file for an upcoming homicide trial-a drive-by shooting in which the victim's girlfriend will take the stand to identify the accused. The defense has retained Pezdek as an expert on the reliability of eyewitness memory.
"For starters," says Pezdek, "I see here that the first time the girlfriend talks to the police, she tells them, 'I didn't actually see the guy's face.' "