The known presence of a weapon has also been shown to reduce the accuracy of eyewitness recall, often referred to as the "weapon-focus effect". This phenomenon has been studied at length by eyewitness researchers. They have consistently found that eyewitnesses recall the identity of a perpetrator less accurately when a weapon was known to be present during the incident. Psychologist Elizabeth Loftus used eye-tracking technology to monitor this effect. She found that the presence of a weapon draws a witness's visual focus away from other subjects, such as the perpetrator's face.