What causes people to develop PTSD? If we survived the experience, why must we keep reliving it – over and over again? What if there is actually a reason? What if, it served a purpose as we evolved? That is what I want to explore in this week’s blog: Have our brains evolved to be susceptible to PTSD because it was advantageous?
(The science around this is still developing and not all parts of this theory are agreed upon. Consider this as a theory that some researchers agree with and others are not so sure of.)
First, you’ll need a very, very basic understanding of both evolution and brain structure.
Evolution, in a nutshell
The most bare bones concepts of evolution: The creatures that adapt best to their environment will produce the most offspring. Those offspring that continue to adapt best and survive to pass on their genetic codes win. Those that do not survive in their environment do not pass on genetic material and thus die off. Those adaptations that increase our likelihood of reproducing future generations will become the new normal. There are polar bears at the north pole because having white fur makes it easier to hunt. Having enough food means that you succeed in producing more cubs and passing on your white fur to future bears at the north pole. This is an extremely simplified explanation that probably will annoy someone who understands evolution better than I.
Brain Structure over simplified
We will also need to know the very basics of how the brain works to consider the evolutionary purpose of PTSD. There are three levels of the brain that are stacked on top of each other. The least evolved part of the brain located at the bottom of the pile is often called the Lizard Brain. It controls vital functions such as our heart beating and maintaining our body temperature. The middle portion is more evolved than the lizard brain but less than the top portion. The middle portion, the Limbic Brain, does emotions and very basic memory (this resulted in something good, this resulted in something bad). This is also the part of the brain that takes control during a danger response (Fight, Flight & freeze). The top, most evolved part of the brain, is the Neocortex. The Neocortex is where reason, language, imagination and abstract thought occur. The Neocortex is where we think, and that only matters to this blog because thinking is slower than reacting.
A Raw data collection system
Let’s imagine we’re a group of early humans. We’re walking through the woods and come upon a pack of bears. Only those that live through this encounter will continue to produce more children. Let’s say half of the early humans survive the bear pack, that’s great but the bears are still out there. Surviving bears once is not enough. These early humans would need to survive the bears repeatedly. Good thing they have their Neocortex, they can think out ways to better survive or avoid the bears in the future. Only one problem, when they are running from the bears, their neocortex is off line. The Limbic brain is in control and in danger response mode. This is where the system that can lead to PTSD comes into play. During the danger response mode observing and considering (neocortex functions) don’t work. So, the Limbic brain that developed a way of grabbing lots of raw sensory data, to be analyzed by the neocortex later, while escaping the bear would have an evolutionary advantage over those early humans whose Limbic brains did not collect raw data for later analysis. Those that collected data could figure out how to avoid the bears in the future while those that did not would have to keep outrunning the bears. It is this raw data collection system that holds the memories that can become the root of PTSD.
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How Does Raw Data Become PTSD?
This raw data collection system is meant to be helpful. This raw data is collected so that after the bears are outran, when the Neocortex comes back on line, the person can examine the collected pieces of memory for helpful clues for future survival or avoidance of the bears. But we don’t usually have to outrun bears in todays world and the traumatic events that lead to activating our danger response system don’t always have useful information for us to contemplate later. This raw data collection system doesn’t care if the person is too young or disempowered to be able to use the information it collects, it simply does its job. When these fragments of raw data are not turned into useful information they can turn into the tormenting flashbacks and pieces of memory that become the root of PTSD.
That this is raw data helps explain why the PTSD memories are so jumbled and fragmented. This raw data memory is often individual sensory experiences (a smell, a taste, a feeling etc.) or short clips that aren’t connected to a whole experience. Sometimes they are random and seemingly meaningless (noticing the color of the leaves or the smell of rain).
How Does Knowing This Help?
Unfortunately, knowing that our PTSD is rooted in a brain function that provided an evolutionary advantage won’t make it go away or stop hurting. What it does do is give us a very valid reason to stop believing that our PTSD is a weakness or flaw in ourselves. Many people who struggle with PTSD blame themselves for having it. This theory shows that developing PTSD is really just our brain doing what it evolved to do. Cutting ourselves some slack and letting go of self-blame is a great step to take and understanding why our brains are susceptible to PTSD can help us achieve this.
It also helps us understand why revisiting those memory fragments can be a vital aspect of the healing process. The brain collects this information during the crisis so that it can be reprocessed later. We need to revisit those raw memory fragments. But how we revisit those memories is also important. If just revisiting the memories was enough, then no one would have PTSD because revisiting the upsetting memories is a core symptom of PTSD. When we revisit the raw memories of PTSD we often relive them. We reexperience the same intense emotions and relive the memories as if they are happening again. Doing this will not help us heal. We need to learn to remember without getting overwhelmed. Only once we can revisit without reexperiencing them can we reprocess them as we need to in order to heal.