Guilt Detection Tests Used By Many Law Enforcement Agencies Can Be Beaten By Suppressing Memories, Research Finds

Some people have the ability to suppress their “incriminating” memories and as a result pass the brain activity guilt detection tests that are currently used by many law enforcement agencies around the world, new research has found. The technology has often been trumpeted as a “fool-proof” way to determine the “guilt” of an individual, but as the new research has shown, those with a particular aptitude for self-control can suppress and control their brain activity enough to pass such tests — demonstrating the ineffectiveness of the (relatively expensive) technology/method.

Image Credit: Court Gavel via Wikimedia Commons
Image Credit: Court Gavel via Wikimedia Commons

Brain activity guilt detection tests are currently commercially available in the US and utilized by a variety of law enforcement agencies and corporations around the world. The technology/method is based on the assumption that “criminals will have specific memories of their crime stored in their brain. Once presented with reminders of their crime in a guilt detection test, it is assumed that their brain will automatically and uncontrollably recognise these details, with the test recording the brain’s ‘guilty’ response.”

That’s quite an assumption, and assumes that people have no self-control or ability to influence their own mind.

And now, the new research, done by psychologists at the universities of Kent, Magdeburg and Cambridge, and the Medical Research Council, has scientifically shown those assumptions to be false. “Contrary to this core assumption, some people can intentionally and voluntarily suppress unwanted memories — in other words, control their brain activity, thereby abolishing brain activity related to remembering. This was demonstrated through experiments in which people who conducted a mock crime were later tested on their crime recognition while having their electrical brain activity measured. Critically, when asked to suppress their crime memories, a significant proportion of people managed to reduce their brain’s recognition response and appear innocent.”

These findings are obviously something that should be taken into account by those that use such tests, especially when you consider that these tests have been used determine the guilt or innocence of individuals with regards to things such as murder.

The University of Kent press release notes:

This finding has major implications for the use of brain activity guilt detection tests, among the most important being that those using memory detection tests should not assume that brain activity is outside voluntary control, and any conclusions drawn on the basis of these tests need to acknowledge that it might be possible for suspects to intentionally suppress their memories of a crime and evade detection.

Or alternately, is everyone that registers as “guilty” on such tests truly guilty of the crime that they are accused of?

Dr Zara Bergstrom, Lecturer in Cognitive Psychology at the University of Kent and principal investigator on the research, said: “Brain activity guilt detection tests are promoted as accurate and reliable measures for establishing criminal culpability. Our research has shown that this assumption is not always justified. Using these types of tests to say that someone is innocent of a crime is not valid because it could just be the case that the suspect has managed to hide their crime memories.”

Dr Michael Anderson, Senior Scientist at the Medical Research Council Cognition and Brain Sciences Unit in Cambridge, commented: “Interestingly, not everyone was able to suppress their memories of the crime well enough to beat the system. Clearly, more research is needed to identify why some people were much more effective than others.”

Dr Jon Simons, of the Department of Psychology at the University of Cambridge, stated: “Our findings would suggest that the use of most brain activity guilt detection tests in legal settings could be of limited value. Of course, there could be situations where it is impossible to beat a memory detection test, and we are not saying that all tests are flawed, just that the tests are not necessarily as good as some people claim. More research is also needed to understand whether the results of this research work in real life crime detection.”

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