Flashbacks are memories that are so vivid that they seem like they happened yesterday even if they occurred years or decades ago. Simply recalling them causes you to reexperience most or all of the emotional reactions you had when they occurred.
Flashbacks may seem like a cruel joke but they actually have a very important purpose.
Flashbacks originate in your emotional brain, in a small area called the amygdala, which is Latin for almond because it is about the size and the shape of an almond. Your amygdala has a very important job. It stays quiet most of the time – in fact its the laziest and least active part of your entire brain – until some event triggers a stress reaction. Your stress hormones then turn on your amygdala and causes it to start to create flashback memories of whatever you are seeing, thinking, hearing, smelling or experiencing.
So when you are having a lovely hike in the woods – feeling totally calm and enjoying the scenery – your amygdala is quiet.
Then when a 500 pound bear starts moving towards you, your fight-or-flight reaction kicks in. Within a few seconds your heart is racing at 170 beats a minute, your stomach stops digesting food and all the blood moves to your arms and legs to prepare you for action. You turn and look nervously to the left and right to figure out just how you can get to your car before the bear gets to you. You raise your left eyebrow in surprise and yell ‘oh noooo!’ Suddenly you exhale a massive sigh of relief as the bear turns around and runs away.
While you were defending your life your amygdala was busy creating a flashback memory of the event. The flashback not only records everything that you saw but it also records all of your thoughts, emotions, actions and bodily reactions.
This was a life-and-death situation where you didn’t know what to do. Your amygdala recorded everything that happened – much like a cockpit recorder on an plane – so that if you happen to survive it you will be able to instantly replay all the reactions that kept you alive.
So when you see a bear in the zoo a month later your emotional brain subconsciously activates the flashback memory. This is like hitting an instant replay button. All of a sudden you only reexperience the fear from the time the bear chased. But that’s not all, you also have the urge to look left and right, raise your left eyebrow and shout ‘oh noooo!’ Your brain does the exact same thing because it doesn’t know if it was looking left and right, raising your left eyebrow or screaming ‘oh noooo!’ that did the trick.
So just to be safe your flashback hits the instant replay button and you redo all of your reactions – no matter how ridiculous it may look to everyone else at the zoo.