"Nature versus nurture" is a common phrase used to highlight the two viewpoints on how people grow into unique individuals. Scholars, scientists, psychologists, physicians, and the general public all provide a range of viewpoints on this topic. Some say humans evolve all based on genetics, some say we are all a direct result of our environment, and some say we're a byproduct of both nature and nurture.
Nature consists of our genetic makeup which in turn, dictates our behavior including personality traits and abilities.
Nurture encompasses all the factors of the environment and how experiences and upbringing influence behavior.
After working with various populations in the counseling field, it has become organically evident that in terms of trauma, which technically would fit in the "nurture" category can also influence genetics as well. This is through a process called epigenetics.
Epigenetics is a term used to describe how behaviors and the environment can change how your body reads a DNA sequence. This results in changing the expression of genes.
During development, the DNA accumulates chemical marks or indicators of how each gene is expressed. The chemical marks are referred to as "epigenome." Early life experiences such as childhood trauma, can drastically impact how a gene is expressed. The marker on the gene can then be permanent or temporary. The expression of genes that falls into the "permanent" category can then be easily passed down to the next generation and "switched on" when environmental factors trigger that marker. In a sense, it is as if our genes can be dormant until environmental triggers "nurture" the gene which allows for the gene to become "active" or expressed through behavior and personality.
Research shows profound evidence of this process. Here are a few examples:
The Dutch Hunger Winter Case Study - marked the period after World War II when the Nazis blocked food supplies from reaching the Netherlands. This resulted in more than 20,000 deaths caused by starvation. Scientists examined case studies of women and their children who survived the famine. Of the women who were pregnant during the Hunger Winter, their children were all noted to be a few pounds heavier than other children. When scientists looked into the biomarkers of these children, they found indications of high cholesterol and triglyceride levels, and higher rates of obesity, diabetes, heart disease, and psychotic disorders. The scientists further noted these children all had a chemical marking on one of their genes. So in this example, the mother's body recognized it was not receiving fuel and, as a result, deactivated the gene responsible for metabolism in order to conserve the body's nutrients and energy.
9/11 Survivor Case Studies-individuals who were directly affected by 9/11 showed an epigenetic marker in both parents and unborn children that minimized the level of the stress hormone, cortisol. You may be thinking, "low cortisol is good, right?" Well, in the case of baseline levels, it's not good. We all naturally have a rise in fall in cortisol every day. It's synced to our circadian rhythm and allows us to be alert and energized during the day. A spike in cortisol above baseline occurs whenever we perceive we are in danger. That spike initiates our stress response system called the sympathetic nervous system which is crucial for survival when we are in imminent danger. Low cortisol levels translate to that system not working as it should. This can result in symptoms such as fatigue, depression, anxiety, autoimmune issues, low resiliency, disordered eating, etc.
Mice Studies- In 2001, a researcher by the name of Isabelle Mansuy, designed many interventions with mice that re-created aspects of childhood trauma. In her studies, she experimented with exposing parent mice to stress and studied the results in the offspring. Her studies evolved for nearly 15 years, studying different variations of genetic trauma. She concluded that traumatized adult mice produced offspring that rated higher in risk-taking behavior and depressive symptoms. She also noted molecular changes in the inherited behavioral traits in offspring mice. In 2016 she published results that illustrated a "solution" so to speak to reversing the generational trauma. She noted that the offspring of traumatized parents did not show biomarkers if they experienced a safe and nurturing upbringing. The mice that had a "luxurious" living environment - one that stimulated different brain regions and social interactions, did not show indications of the epigenome markers.
These are just a few studies to aid in visualizing this epigenetic process. While this is a topic that is widely discussed in the field of psychology and neuroscience today, there are still many limitations to studying this concept in an ethical and clinical way with human subjects. The case studies do however provide significant evidence of generational trauma.
Another theme of genetic trauma includes "historical trauma- a concept that includes the cumulative, massive, and chronic trauma imposed on a group across generations and within the life course" (Brave Heart & DeBruyn, 1998; Duran, Duran, Brave Heart, & Yellow Horse-Davis, 1998). The oppressed group has undergone years, sometimes decades of systematic oppression which reinforces feelings of unresolved grief, fear of majority groups, and sometimes anger regarding the historical oppression. Historical trauma is rated as perpetual when traumatic ancestral pasts create additional adversity in the present day or issues of inequality continue to be unresolved. Microaggressions also contribute to triggering historical trauma. Microaggressions are "commonplace daily verbal, behavioral or environmental slights, whether intentional or unintentional, that communicate hostile, derogatory, or negative attitudes toward stigmatized or culturally marginalized groups."
Takeaways
Any traumatic event that causes deep distress in one generation, can be passed down to the next generation. This can occur through epigenetics, learned behaviors, and social and psychological pathways in the brain. While this information may seem depressing, having this information can help in understanding why some people experience mental health issues without a known trauma or cause. It also may explain how family conflict, and adverse childhood experiences in parents, can influence children's well-being and affect them throughout their lifespan.
Ways to "reverse the cycle"
Identify ansestral trauma. This doesn't have to be specific but understanding what ancestors went through can help you make sense of why your parents had the parenting style they did or why there were underlying mental health issues in your family or with you individually.
Work towards processing the trauma through acceptance, family work, therapy, etc. Understand the ingrained behaviors, beliefs, and patterns that stem from generational trauma so you can then be more conscious and intentional about your own behaviors and tendencies.
Set healthy boundaries. generational trauma may consist of family members that feed into unhelpful or unhealthy patterns. It's ok to set healthy boundaries with individuals if they are causing distress or modeling old patterns that do not fit in with your values.
Practice self-care to help reduce any tension and stress your body may be carrying.
Allow yourself to grieve. Acknowledge your feelings, let them out, and highlight your needs.
Seek social support. Love and belonging are two of the most essential ingredients for a fulfilled life. Trauma healing that takes place without support can be unsuccessful. Finding others who accept you, and your background, and are there to help you reach your goals is essential.
Sources
Catherine Elizabeth Burnette, Charles R. Figley. (2017) Historical Oppression, Resilience, and Transcendence: Can a Holistic Framework Help Explain Violence Experienced by Indigenous People?, Social Work, Volume 62, Issue 1, 1 January 2017, Pages 37–44, https://doi.org/10.1093/sw/sww065
Jarvis, P. (2021). Ancestral Selfies and Historical Traumas: Who Do You Feel You Are? Genealogy, 6(1), 1. MDPI AG. Retrieved from http://dx.doi.org/10.3390/genealogy6010001
Parents’ emotional trauma may change their children’s biology. Studies in mice show how. (2023, March 16). Science | AAAS. https://www.science.org/content/article/parents-emotional-trauma-may-change-their-children-s-biology-studies-mice-show-howWhat is Epigenetics? The Answer to the Nature vs. Nurture Debate. (2020, October 30). Center on the Developing Child at Harvard University. https://developingchild.harvard.edu/resources/what-is-epigenetics-and-how-does-it-relate-to-child-development/
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