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Evolution and the Unconscious Mind

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Joanna Barkas

Evolution and the Unconscious Mind

It is often misconceived that the conscious mind is the portion of our brain that is most active and consequently, must be the largest and most significant division of the brain.  Even the term “subconscious”, which is often used interchangeably with the term unconscious, implies this frivolous or “sub-par” nature of this portion of the mind when compared to the conscious mind.  However, the unconscious mind is filled with feelings, memories and thoughts that we may be unaware of, but that may have a lasting and significant effect on what we perceive to be conscious thoughts and actions. 

            Walt Whitman and Siri Hustvedt address this notion of the unconscious mind and both incorporate its significance and its effects into their writing.  Both Whitman’s unconscious form of writing and Hustvedt’s incorporation of dreams, psychoanalyses and diary entries within her text, indicate that perhaps, both trust the unconscious mind to provide us with something invaluable-perhaps even more valuable than what the conscious mind can provide us. Whereas Whitman attempts to prove to his readers that the unconscious mind can be interesting and useful, Hustvedt takes her message a step further by attempting to show her readers the effect of trauma on the unconscious and how this can be potentially useful or even detrimental.  When considering both the messages of Whitman and Hustvedt, it is possible to conclude that trauma and the way in which the unconscious mind stores and manipulates such information is a key component of cultural evolution and perhaps has even proven to be evolutionary advantageous to humans.   

            The human unconscious is connected to the body and consequently, any stimulation of the unconscious can result in a number of physiological responses.  For example, if considering hypnosis or sleepwalking as an activation of an individual’s unconscious, then it is possible to see how the unconscious can be linked to physiological responses in a very immediate way, as is the conscious mind.  This connection of the unconscious mind with the body and physiology can be the result of an encounter with something that can be potentially harmful or life-threatening. Such a traumatic experience will affect the unconscious in any number of ways, but most likely by storing this memory.  If a person were to come into contact with the cause of the trauma again, the unconscious will most likely be activated and there will be a number of apparent physiological consequences, such as increased heart rate and sweating.  In such a scenario, there was no need for a conscious response after sighting the possible danger, as the body already begins to respond to the danger prior to any conscious physiological response, such as running.         A clearer example of trauma affecting the unconscious and resulting in a physiological response is Post Traumatic Stress Disorder (PTSD).  Individuals who suffer from PTSD have experienced a traumatic experience that has affected their unconscious in such as way that may result in physiological responses such as racing heart or sweating, being on edge or having outbursts. [3] Any one of these responses can be triggered by a memory or something that vaguely resembled a memory that led to what may have appeared as a conscious and voluntary physiological response.  Thus, it is evident that the unconscious mind is connected to our body and can result in any number of physiological responses when stimulated.

            If our unconscious is capable of eliciting a response from our body quicker than our conscious is able to elicit such a response, then it is possible that the unconscious provides humans with an evolutionary advantage.  The bodily response to the same traumatic event that was once experienced or a similar one resembles the body’s immune system.  Similar to the immune system that builds up antibodies to an antigen that the body was once exposed to, the unconscious also stores this memory, ready to elicit a physiological response when it is again exposed to a similar scenario.  In that sense, as humans, we depend on our unconscious to provide us with a significant amount of rational thought and reasoning, which would eventually lead to a response that may otherwise not have been available to us in a specific instant.  This quick response provided by the unconscious would prove to be evolutionarily advantageous for early humans.

            In a recent New York Times article regarding this notion of the unconscious as evolutionarily advantageous for humans, psychologist Dr. Bargh states that, “unconscious goals can be seen as open-ended adaptive agents acting on behalf of the broad, genetically encoded aims-automatic survival systems.”[1] If we consider the unconscious to be an “automatic survival system” then it is possible to understand how the storing of traumatic memories within the unconscious can be evolutionary advantageous.  Within an early hunting and gathering society, for example, a traumatic experience may include encountering a large animal in a particular area.  By storing such a memory, the unconscious will avoid that particular area or any area that resembles the one in which the traumatic event had been experienced.  Furthermore, if a similar traumatic event were to be experienced in the future, the unconscious would be able to elicit a physiological response much faster than the conscious mind would otherwise be able to make a rationalization, which would then be followed by a response.  Therefore, such storing of a traumatic memory within the unconscious would prove to be evolutionarily beneficial for early human societies.  

            More recent studies show that perhaps the physiological component related to the unconscious is not the only beneficial voluntary adaptation of that portion of the mind.  In recent studies, it was found that an object such as a briefcase within proximity of an individual will result in a more competitive nature at that time, whereas having individuals read words such as “dependable” and “support” will result in a more cooperative nature. [1] Psychologists explain such phenomena by stating that these responses are due to “everyday sights, smells and sounds that selectively activate goals or motives that people already have.”[1]  Such a response due to the unconscious would result in a modern beneficial evolutionary adaptation within the context of cultural evolution as “selectively activating” positive responses that would be considered evolutionarily adaptive within a cultural context allows for these positive “motives or goals” to be selected for.

            Although the unconscious and particularly, trauma and its effects on the unconscious may have proven to be evolutionarily advantageous to early humans and may continue to be advantageous to us today, when the effects of trauma and the unconscious begin to dictate all of an individual’s actions, it becomes difficult to  move forward.  As illustrated by Hustvedt in her novel, it became difficult for any of the characters to move forward because they were consistently dwelling on past trauma and the effect on their unconscious.  Similarly, anxiety disorders such as Post Traumatic Stress Disorder are extreme cases of trauma’s effect on the unconscious.  Although PTSD is a good example of how the unconscious is directly connected to physiological response, and thus, how the unconscious may serve as an evolutionary advantage, PTSD itself is not an evolutionary advantage.  This is because for an individual with PTSD, their unconscious mind begins to dictate their lives, making it difficult to move past the trauma.  Therefore, in order for the unconscious to continue to be evolutionarily advantageous for humans, there needs to be a balance between an individual’s use of the unconscious mind and the conscious mind. 




1) Carey, Benedict. "Who's Minding the Mind?" New York Times 31 July 2007. 31 July 2007 <>.

2) Hustvedt, Siri. The Sorrows of an American A Novel. New York: Henry Holt and Co., 2008.

3) "Post-Traumatic Stress Disorder." National Institute of Mental Health. 02 Apr. 2009. National Institute of Mental Health. 16 Apr. 2009 <>.

4) Whitman, Walt. Leaves of Grass The Original 1855 Edition (Thrift Edition). Minneapolis: Dover Publications, 2007.





Paul Grobstein's picture

conscious/unconscious interplay

"in order for the unconscious to continue to be evolutionarily advantageous for humans, there needs to be a balance between an individual’s use of the unconscious mind and the conscious mind."

I am, and I can think, therefore I can change who I am?