Loftus et al

Loftus et al

1. Aim: To provide support for the 'weapon focus' effect when witnessing a crime.

2. Pps: 26 University of Washington students aged 18-31. They received an incentive for participating.

3. Procedure:

   • 2 sets of slides were shown. The 18 slides in each series showed people queuing in a 'Taco Time' restaurant.
   • In the control group person B (the person 2nd in the line) hands the cashier a cheque.
   • In the experimental group person B pulls a gun (the independent variable).
   • All the other slides in both series were identical and shown for 1.5 seconds.
   • The pps were told it was a study of proactive interference.
   • The dependent variable was measured by a 20-item multiple-choice questionnaire.
   • The pps were also given a line up of 12 head-and-shoulder photos in a random order and were asked to rate how confident they are of their identification on a scale of 1-6 (1=guess 6=very sure).

4. Results:

   • Answers to the questionnaire about the slide show showed no significant difference between the two conditions..
   • Chance performance on the photo line-up was calculated to be 8.5%.
   • In the control condition 38.9% chose the correct person B against 11.1% in the weapon condition.
     • The result is significant.
   • There was no difference in the confidence level of either group.
   • Eye fixation data showed 3.72 was the average number of eye fixations on the gun in comparison to 2.44 on the cheque.
     • This is also significant.