There Are Two Ways To Purposely Block Out Memories, Study Suggests

If you've ever purposely blocked an embarrassing moment from memory, a new study reveals just how your brain did it.

The research, published in the journal Neuron, shows that there are actually two ways we're able to voluntarily forget things. The first way is to essentially stop the brain's remembering system from working, while the second way is to have a substitute memory for the brain to remember instead of the one we want to block out.

"A better understanding of these mechanisms and how they break down may ultimately help understanding disorders that are characterized by a deficient regulation of memories, such as posttraumatic stress disorder," study researcher Roland Benoit, of Cambridge University's MRC Cognition and Brain Sciences Unit, said in a statement. "Knowing that distinct processes contribute to forgetting may be helpful, because people may naturally be better at one approach or the other."

Researchers were able to discover these two methods of forgetting by conducting fMRI brain scans on volunteers as they remembered, and then purposely forgot, associations between word pairs. They forgot the associations by either trying to block them out entirely, or by trying to think about other things that would replace their memories of the associations.

The researchers found two different brain processes for both of these methods. For the first one, the dorsolateral prefrontal cortex part of the brain worked to stop activity in the hippocampus brain region. For the second method, substitution of memory was linked with activity by the caudal prefrontal cortex and midventrolateral prefrontal cortex brain regions.