Amsterdam coffee-shop study explores the effects of cannabis on eye-witness memory

With cannabis' fairly new place in the scientific community it's not surprising that there have not been a wide range of studies involving the specific effects of cannabis. Researchers at VU University Amsterdam performed a study recently that had only been performed once before 20 years ago and it involves the memory and recall accuracy of someone intoxicated by cannabis. In the test researchers showed Amsterdam coffee shop patrons a video of a robbery, a number puzzle and 2 memory tests and the results are not exactly as expected. While those intoxicated did not describe as many details of the crime as the sober subjects, they both accurately identified the subject or were able to note his absence at the same rate. What was interesting was that those under the influence of cannabis actually had more confidence in their correct identifications or note of absense than their sober counterparts. Not only is being able to identify suspects one of the most crucial parts of an investigation, but the confidence in a witness' answer also plays a large role in the a jury's confidence in convicting a suspect.

However, on the line-ups, the cannabis intoxicated participants performed just as accurately as the sober participants, both at correctly identifying the suspect if he was present, or correctly noting his absence if he wasn't there. What's more, the intoxicated participants were more confident in their judgments, and there was a stronger correlation between their confidence and accuracy. The researchers surmised this greater insight could be due to the known effect of cannabis on increasing introspection and internal focus. This finding too could have real-life implications since it's known that jurors and judges are influenced by witnesses' confidence.