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Maass and Kohnken (1989)

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William van Hoek

on 27 November 2014

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Transcript of Maass and Kohnken (1989)

Participants completed questionnaires that seemed to be investigating physical activity and psychological well being.
One example of a question was whether or not the the participants were scared of injections.
Then taken to a experimental room with actual physiological equipment and breathing monitors.
To investigate
weapon focus
as a factor in
eyewitness effectiveness
Using a
as a weapon
86 non Psychology students were told that they were doing a study that was studying physical activity and psychological well being.
Approached by woman (wearing a lab coat and stethoscope) with injection or with a pen.
The woman said that:
She would give them an injection
She wouldn't give them an injection
After 20 seconds she left and the researcher strolled in.
High in ecological validity as the participants experienced real emotions. As a result, their behaviour was more natural.
The study shows that eyewitness testimony is not always reliable. If the witness focuses more on the weapon rather than the criminal/offender.
Ethics of the study could be questionable as the participants' full formed consent wasn't given. However, it can be argued that health checks were given and that after the study all participants were fully debriefed.
All the participants were university students and the results can therefore not be generalised to the rest of the population. The older or younger population could have reacted differently.
Syringe exposed participants performed worse in the identification.
68% gave a wrong identification.
Only 33% of the pen exposed people identified wrongly.
The less facial detail was remembered, the greater their fear of injections.
Some could identify the colour of the syringe.

Maass and Kohnken (1989)
Participants paid more attention to the syringe than the pen which led to a reduced identification performance.
Results support the idea that weapon focus decreases the attention, peripheral details and thus the memory and recall.
Weapon focus interferes with attempting to recognise the attacker later.
Attentional factors may contribute to the weapon effect.
Kohnken (1989)

Weapon focus - the effects on the ability of witnesses to describe the circumstances surrounding a crime due to their focusing on the presence of a weapon
Usually results in the eye witness being unable to identify the perpetrator and unable to recall key points
Maass and Kohnken wanted to create
an unusual situation.

20 minute delay
Asked to identify woman in target line up
Participants asked to recall details of face and hands.
Full transcript