Do you recognize this moment: you are telling a story about the past and someone else says that it never happened like that at all. You are convinced though, that you actually experienced this event in the way you just told your friends. Are your memories false?

Yes, it’s is an example of false memory. You remember something wrongly. Or certain things that never happened at all, are in your head as something you have actually experienced. It’s more common than you think. And there’s one substance that makes you more susceptible to it, according to researchers: THC.

Misinformation and false memories

Research from Maastricht University in the Netherlands shows that cannabis makes you more sensitive to false memories. According to this research, people who are under the influence of THC, are more susceptible to misinformation. And they even come up with totally false memories!

Among friends, retelling such a false memory, is not so bad but it can be a little embarrassing though. Of course, this is a different story when the police have to interrogate an eye witness to a crime. Because of THC a person’s story could not be consistent with what he actually saw.

Talking about events that never happened

People can associate things differently under the influence of THC. As a result, they can even create completely new memories of events that never happened. Of course, those testimonies aren’t very credible. This is quite a big problem because an eye witness testimony is often an important piece of evidence in a lawsuit. It can really make or break the case.

It is therefore important that such testimony is properly administered. This often happens quite quickly after an incident has occurred, because the incident is still fresh in the memory. However, this research showed that it is sometimes better to wait a while before questioning witnesses and suspects. It appears that the THC level in the body of an eyewitness has an influence on the witness statement. Perhaps even more than thought.

About the research

The study took place among 64 healthy people. These people were not unfamiliar with smoking cannabis but weren’t heavy users either. Half of them inhaled a dose of vapor with THC and the other half inhaled vapor without THC. The researchers did not tell the subjects who inhaled vapor.

The subjects’ memory was tested several times: immediately after inhalation and a week after. With the help of virtual reality, test subjects experienced different scenarios. Some of the subjects witnessed a crime, and others had to commit a crime themselves.

At the same time, someone was telling about the event. But in the process, he made some mistakes on purpose. Some of the stories he told matched what happened, some didn’t. So this person partly gave false information. The subjects were interviewed for half an hour after the trial. Those who inhaled THC were found to take the false information in easier. This was however limited to the phase of acute intoxication.

Investigators’ advice to the police

It has been known for some time now, that the use of cannabis affects the memory of users. But smoking also seems to affect hów you remember things. Researchers advise police to wait with questioning witnesses and suspects who are under the influence. At least until the cannabis has lost its direct effect. This greatly increases the chance of a reliable statement.

We also wonder where you can register for this type of research. First smoke a joint and then commit a crime in a virtual world. All in the name of science, we don’t say no to that!

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We hope your memory is clear as water when you try to find your way to your favorite coffeeshop in Amsterdam. If not, don’t panic. You can find us on Google Maps.