One night she happened to be watching a James Bond movie when a close-up of a shark flashed onto the screen. “I came unglued, blubbering and crying,” she recalls. After extreme trauma, memories combine in odd ways to produce flashbacks that are even more vivid than reality. Glenn never actually saw the teeth of the shark that attacked her. But in her flashbacks, she saw an open mouth coming at her bristling with teeth.
People who have not experienced flashbacks tend to underestimate their power. They aren’t just annoying memories. A true flashback is an all-out assault on the emotional system that takes control of your senses and your behavior and can wipe your memory as clean as electroshock therapy does. One veteran of the Vietnam War came out of a flashback standing in a forest in Ohio wearing battle fatigues. He had no notion of how he’d gotten there. Glenn had similar experiences. In one case, she started out sitting in a restaurant waiting to pick up a pizza and later found herself curled up in a ball on the floorboard of her truck with no memory of what had happened in between.
This new and fearful Micki drove her absolutely crazy. Glenn had reveled in her life and in her fearlessness. What sort of woman goes diving with sharks for her vacation? One who is not afraid. “The things I did, such as stepping off the Okaloosa Island Pier into an 18-foot crest in a hurricane surge, galloping my big Swedish Warmblood horse, Gent, in the woods around Eglin Air Force Reservation at night and watching the tracers from the gunships that were doing night ops—those aren’t just things I do,” she says. “That’s who I am.”
But after the shark attack, Glenn felt as if she’d been cloven into two identities: “The Micki I loved was loud and clear in my head. But the new Micki—injured, careful, timid—emerged as the dominant me, and to my dismay she controlled my actions, my body.”
One of the things bedeviling Glenn had to do with a certain type of memory we store. At the simplest level, these “mental models” are representations of objects that allow you to identify things quickly and to know the rules by which they behave. That’s a bunny. It hops away when I enter the yard. That’s a bird. It flies away.
The retina sends images to the visual cortex, which makes a prediction about what is being seen and forwards it to the thalamus. The thalamus returns a message telling the difference between the actual visual information and the prediction. The part that’s correctly predicted is ignored. Whatever is new then serves to revise the mental model for future use.
The emotional system labels our mental models so that we instantly know their value or danger. You don’t really see what’s in the environment; you take in sensory information and try to match it to what you expect based on experience or some innate model. Extreme trauma, however, can destroy your trust in your mental models. This condition is known as hypervigilance, and it makes sense. A Vietnam War veteran told a researcher he had to look at everything twice to be sure of what it was. Since mental models are the heart of all perception, distrusting them makes you question your entire world, and this can be the source of much pain.
To a young child, a pile of clothes in the corner of a dark bedroom might look like the face of a monster. A shadow might be a terrifying bird. Those are perfectly reasonable interpretations to a brain that has few mental models—especially at night, when children are instinctively on the lookout for whatever is dangerous. In that sense, post-traumatic stress can make us behave as if we were children again. And like a child, Glenn was now afraid of images of sharks.
Her husband had an idea about fixing that. He had managed to photograph the shark just before it attacked her. Now he put a close-up of that image on her computer. Her screen saver became the monster from the deep that stole her life away.