Lably
Skip to content

Weapon focus

Eyewitness memory bias

  • 16 min read
  • 5 chapters

Related on Lably

Through Memory, Attention and Phenomenon

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 author conducted several studies in 1987 and finally demonstrated the viability of weapon focus. The study conducted by Johnson and Scott (1976) represents one of the few early simulation studies available, likely due to the ethical issues surrounding the exposure of research participants to a putatively threatening scenario. For this reason much of the research conducted on the weapon focus effect has made use of videos or slideshows. In one of the first such experiments, Loftus, Loftus and Messo (1987) had participants watch a video in which a young man approached the counter of a fast food restaurant, presented an object to the cashier, accepted money and left. In the control condition the man presented a cheque to the cashier whereas in the weapon condition the man presented a gun. Specialized equipment tracked the participant's gaze as they viewed the video to determine with what frequency (and for how long) they fixated upon the item of interest (the cheque or the gun). Relative to the control condition, participants in the weapon condition looked at the item the man was holding more frequently and for greater duration. Further, when tested for the details of the event, performance was better for the control condition relative to the weapon condition - with the exception that participants in the weapon condition were more likely to recall what object the man was holding (a gun).

Another significant challenge to the studies on the weapon focus effect has been their ecological validity. Specifically, many theorists have argued that the effect is limited to the laboratory design. These claims have been supported by the relative absence of applied evidence supporting the effect. Several reports have been published looking for evidence of a weapon focus effect using records of actual crimes. According to the laboratory findings summarized above, the prediction had been that eyewitness memory would be worse for weapon crimes compared to non-weapon crimes. Many primary studies have failed to support this prediction. Even so, a recent meta-analysis conducted by Fawcett et al. (2013) has demonstrated that when the data for all of the applied studies are combined, there is a small but reliable effect suggesting that weapon presence impairs actual eyewitness memory. This is extremely significant when one considers how jurors tend to overvalue eyewitness testimony. This finding adds to the ecological validity of the laboratory studies conducted on this topic. One reason why this effect's ecological validity may be hard to support could be the difficulty in testing this effect on actual eyewitnesses and their memory of a crime.

On the other hand, a study published in 2004 found the opposite when confronted with weapon focus. It found that the exposure to firearms was associated with significantly better eyewitness descriptions especially regarding basic features such as gender, height, build, age, and ethnicity.

Sign in to keep reading

4 more chapters are free with a Lably account.

More in Psychology