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Memory for License Plates as a Function of Exposure Time

NCJ Number
107227
Journal
Journal of Police Science and Administration Volume: 15 Issue: 1 Dated: (March 1987) Pages: 68-71
Author(s)
L Mende; D P MacKinnon; R E Geiselman
Date Published
1987
Length
4 pages
Annotation
This experiment examined the accuracy of memory regarding license plates and identified the pattern of errors made when recalling license plate numbers after either long or short exposure.
Abstract
The subjects were 107 undergraduate students enrolled in an introductory psychology course at the University of California, Los Angeles. Subjects viewed a series of nine slides in which a male suspect appeared to load a stolen television set into a car and drive away. In each slide, the license plate was filmed from a different angle and distance with varying degrees of clarity. Subjects were randomly assigned to two viewing conditions: a rate of 5 seconds per slide and a rate of 2 seconds per slide. After the viewing, subjects were given a written distractor task followed by the license plate memory test. Only one out of five witnesses recalled the entire plate correctly. The data suggested that transposition errors are infrequent and that visual or acoustical errors are infrequent. To enhance recall, a more fruitful approach would be to try letters that are adjacent in the alphabet to those given by the subjects, regardless of the exposure time. No pattern of errors was detected for numbers. Tables and 11 references.