Tell us a story, Mr. Brain

We're all no doubt familiar with the sensation of fear undercutting rational thinking and response. Some stimulus triggers the willies, and suddenly your reactions become exaggerated well beyond what you'd consider normal for somebody else.

Psychologist Martha Stout, who helped make sense of a particular kind of senselessness with her alarming book "The Sociopath Next Door," gives a fascinating biological account of how fear short-circuits reason in her more recent "The Paranoia Switch."


Under normal circumstances, the hippocampus part of the brain acts as an efficient and wise traffic cop, integrating sensation with emotional input and assigning ordered reactions accordingly. The result is that after a normal-to-pleasant event, you can mentally reconstruct not just the event but the emotions associated with it. You can build a story, allowing the event to inform and enrich future interactions with the world.


If an event sets off your fear response, however, your hippocampus quickly gets overwhelmed with the urgent emotional messages being broadcast by your limbic system. Memories of the event come together haphazardly and in fragments. "They remain in the brain as incoherent memory traces and sensations, constituting a cruel little hair trigger, a paranoia switch."

When something happens that reminds of you of that traumatic event, you have no coherent story to guide your emotional reactions. Instead, you're stuck in that greatest of fear factories, the unknown, re-experiencing that original limbic tornado.


Fortunately, our brains don't stop at the hippocampus. We have that big ol' cortex, which allows us -- with a lot of practice, attention and effort -- to build reasonable, useful stories even around the nasty stuff.