Surprise and False Memories

Surprising the study participants during memorization led to false memories.

Summary: Memory editing occurs on the fly, leaving the brain susceptible to creating memories that may not be accurate.

Memory editing is mostly a good thing, as it enables us to learn from our mistakes and integrate new information with old experiences. But the ability to edit leaves open the possibility of creating false memories as well.

On the third day, participants were interviewed in great detail to try to recall as much of the videos as they could. “A couple of people were incredibly detailed and super accurate, but a couple of people had an insane number of false memories,” Sinclair said. “It was hard to keep a straight face.”

What the researchers saw in the MRI images is that surprise changed the role of the hippocampus, a brain region important for creating, retrieving, and editing memories. After unsurprising videos, the hippocampus seemed to be in “preserving mode,” strengthening memories. But after surprising videos, the hippocampus switched into “updating mode,” getting ready to edit memories. Surprise disrupted the stability of patterns in the hippocampus, showing this mode switch. More pattern disruption led to more false memories, and people were more likely to have false memories for the surprising videos that had been interrupted.