The study has shown that people can intentionally suppress incriminating memories and thereby avoid detection in brain activity guilt detection tests.
Such tests, which are commercially available in the United States and are used by law enforcement agencies in several countries, including Japan and India, are based on the logic that criminals will have specific memories of their crime stored in their brain. When presented with reminders of their crime, it was previously assumed that their brain would automatically and uncontrollably recognise these details. Using scans of the brain’s electrical activity, this recognition would be observable, recording a ‘guilty’ response.
However, research by an international team of psychologists from the universities of Cambridge, Kent and Magdeburg as well as the Medical Research Council, has shown that some people can intentionally and voluntarily suppress unwanted memories.
For the study, the researchers had participants conduct a mock crime. These people were later tested on their crime recognition while having their brain activity monitored using electroencephalography (EEG). Critically, when asked to suppress their crime memories, a significant proportion of people managed to reduce their brain’s recognition response and appear innocent.
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Image: Dr Zara Bergstrom (right) and Dr Jon Simons (centre) examine the electrical brain activity of another of the paper's authors, Marie Buda (seated).
Credit: Department of Psychology
Reproduced courtesy of the University of Cambridge
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People can ‘beat’ guilt detection tests by suppressing incriminating memories
4 June 2013
Brain scans that claim to be able to determine whether a criminal is guilty of a crime can be fooled, new research reveals.