Evolutionary Psychological Lag Complicates Stress Reactivity

Stress today is driven by processes formed long ago.

Reviewed by Monica Vilhauer Ph.D.

Key points

• We often do not understand why we are stressed or react the way we do to stressors.
• Our brains do not work rationally during stressful encounters.
• Society has evolved, but our stress response system has not caught up.

Your boss tells you that you need to do a presentation next week. Immediately, your hands begin to sweat, your stomach develops butterflies, your heart rate increases, your breath shortens, and your mind momentarily blanks out.

After a few moments, you regain a bit of control and start to envision yourself actually doing the presentation in front of a group of people. You see yourself tripping over words, picture your audience seeing your hands shake, get a glimpse of yourself being criticized by the crowd, or feel the sense of having your mind go blank, forgetting everything that you know.

All of this after simply being told you had to present!

This is a common scenario, as many people are terrified of public speaking. Although there are many psychoneuroimmunological factors at play, in addition to developmental issues, coping mechanisms, operant conditioning, and even genetics, let us look at one central driving force.

Our brains lag...

Society, culture, knowledge, and technology have all dramatically changed over the years, decades, and centuries; however, from a stress reactivity standpoint the human brain has not evolved equally. In fact, when we encounter stressors, our brain still reacts as if we were on the grasslands of Africa, where we had to fight for our lives from predators and competing clans. These potentially deadly situations humans encountered are known as emergent stressors — what our stress system is designed to protect us from: harm or death (Comer, 2020).

But even today, with no lurking tigers, our responses to stressors are based on these evolutionary principals and are driven by deeply rooted psychoneuroimmunological factors, involving interactions among hormones, neurotransmitters, and cytokines — or immune system molecules (see my post "Beyond Stress and Burnout: What is Psychoneuroimmunology?").

These responses are further solidified developmentally and operantly throughout our lives, becoming unconscious habituated responses. This results in biochemical reactions, producing identical behavioral responses of repetitive automatic patterns that are far beneath our conscious reality.

As I discussed in my post "Fight or Flight is Just One Part of Stress Reactivity," our habituated patterns can be adaptive responses, benefitting us, or maladaptive responses, hindering us. These complicated developmental and neurochemical processes are largely responsible for our species survival; however, they are not so beneficial when giving a presentation or encountering any other non-life-threatening stressor.

As soon as a presentation was announced, the evolutionary brain detected a threat and the amygdala took over, initiating a cascade of neurotransmitter, hormonal, and immune system excitation, leading to the full engagement of the sympathetic nervous system, causing the well known fight, flight, or freeze stress reactive response.

The amygdala, or emotional center of the brain, takes 30 milliseconds to respond to stressors, but the pre-frontal cortex (PFC), or logical center of the brain, takes 250 milliseconds (Comer, 2020). This delayed PFC time may not seem like long, but it is an eternity from the context of the stress response system that enables you to react without thinking, which, when being attacked by a lion, is quite helpful.

Unfortunately, reacting without thinking to non-emergent stressors, like speaking, is rarely beneficial, particularly with your neurochemicals hyperaroused.

This response can cause anxiety and stress, but it can also get you into serious trouble. For example, I spoke at a conference once and was explaining this process to the audience. A young man in his early 20's came up to me afterwards and said that recently he was at a bar with his girlfriend. Another man walked by her and touched her backside inappropriately. So this young man immediately jumped up and confronted the man who touched his girlfriend. Before he realized what had happened he was face to face with much larger and aggressive person. The young man's anger quickly dwindled and he became afraid — he just wanted to get out of the confrontation.

In this case, you have a 20 year old whose PFC was not yet fully developed, who had a large amount of testosterone due to his age, and who had been drinking alcohol. None of these factors combined is a good thing! But now you juxtapose them into the dynamics of a stressful situation where he felt the instantaneous evolutionarily driven need to "defend" his girlfriend. Bar fights are not like they look on TV. People can and do die during a violent encounter. Fortunately, this young man got his PFC working again and was able to back away from the fight with nothing more than a bruised ego.

The goal of your stress reactive system is quite simply to protect you from an emergent threat. Of course, most stressors we encounter in contemporaneous daily life are not truly life threatening events. Most of what we face are what we call daily hassles or symbolic threats, meaning that the potential harm is perceived and not real. But as we learned in the example with the young man, although your stress response system is trying to protect you, it can ironically get you into serious trouble!

Simply understanding that the logical functioning centers of our brains intentionally lag behind the emotional centers can be an important first step to dealing with this well ingrained evolutionary process. Then look at my post "Take Control of Your Stress and Burnout" for more quick tips.

Summary

Stress reactivity is extraordinarily complex. I have only scratched the most basic surface; however, understanding the basics of our evolutionary response to stress can help us grasp why humans react to all stressors, even benign or symbolic ones, with an over reactive emergent response.

This can provide the beginnings for plans to mitigate the effects of a stress response system that is not always helpful in today's times.