Weapon focus is the concentration on a weapon by a witness of a crime and the subsequent inability to accurately remember other details of the crime. Weapon focus is a factor that heavily affects the reliability of eyewitness testimony. This effect involves a witness to a crime diverting his or her attention to the weapon the perpetrator is holding, thus causing memory impairments and leaving less attention for other details in the scene, such as the attacker’s face, clothing or vehicle. Several studies support the notion of weapon focus, particularly in terms of greater attention paid to the weapon and its effects on recognition and recall. Elizabeth Loftus, Yuille and Burns have all been associated with studies showing the existence of a weapon focus effect. Background information In the field of forensic psychology, researchers have validated the weapon focus effect and shown that a witness will remember less about a crime, or the perpetrator of a crime, when a weapon is present, as opposed to if the weapon is not present at an identical crime. As for the reason of the phenomenon, the two leading explanations attribute it to the cognitive arousal of the witness, or to the overall unusualness of the situation. In one of the earliest known investigations of weapon focus, Johnson and Scott (1976) had two groups of participants come into what they thought was a laboratory study of human memory. In actuality, they were to take part in a simulated interaction intended to determine whether the presence of a weapon would influence eyewitness memory for an event. Participants in the control condition sat in a waiting room where they overheard a conversation between two people following which a man exited with greasy hands and a grease pen. In the weapon condition, participants sat in the same waiting room, but instead they heard a violent argument – including furniture being thrown around – following which a man came out holding a blood-stained knife. During a photo line-up, the control participants were more likely to accurately identify the man they saw in the waiting room relative to participants in the weapon condition (49% versus 33% correct identifications). In 1979, initially Loftus postulated that it is an expected occurrence in the event where an individual is highly aroused, such as in the case of a frightening situation. This suggestion was criticized for its lack of supporting evidence, so its