Leah Alkalay (author) and Ashley Chen (mentor)
Imagine an office. A manager walks into the room and gives an employee a short, tight-lipped nod. For most employees, this is considered a normal interaction—the manager is busy or maybe needs some more caffeine. However, for an individual who experienced early childhood trauma, this nod may not seem neutral, but instead may act as a warning signal. She may feel her heart racing and palms sweating as she fixates on what she did wrong to receive this nod.
This may seem like an overreaction to some, but this seemingly benign nod could cause a negative experience to surface from the employee’s past. Their memory is not simply a recording of what happened twenty years ago, but is instead a lens through which she perceives the present. When a child is raised in a high-stress environment, a biological process called “adaptive calibration” may occur, which causes the child’s social memory to prioritize survival-related information (Del Giudice et al., 2011). This specialization acts as a trade off whereby the brain sacrifices the ability to perceive subtle social cues, like boredom or humor, in exchange for the rapid detection of potential aggression.
Survival Memory
Survival memory is a form of implicit, emotional learning that prioritizes immediate reaction over conscious reflection. To understand this type of memory, it is important to look into the interactions between two important brain structures, the hippocampus and the amygdala. The amygdala acts as an alarm system for the brain by processing emotional signals and triggering the fight or flight response. The hippocampus is responsible for explicit memory, providing the context that allows the brain to recognize threats that are no longer present.
During important developmental windows, Adverse Childhood Experiences (ACEs) flood the brain with glucocorticoids (Felitti et al., 1998), stress hormones that act as an internal chemical alarm. In small doses, they are adaptive, but for a child facing constant trauma, these hormones wear down the calm parts of the brain (hippocampus) while stimulating the fear areas (amygdala). ACEs can be divided into three main areas: abuse (physical, emotional, or sexual), neglect, and household dysfunction (witnessing domestic violence, substance abuse, or the loss of a parent). To be considered an ACE, the event must be a severe stressor, occurring before the age of 18 and impacting the child’s ability to cope. ACES are associated with states of amygdala-hippocampal uncoupling, marked by hyper-reactive, enlarged amygdalas and an under-functioning hippocampus (Giotakos, 2020).
The result of this process is a memory system that is really good at recording fear, but poor at remembering the context. Hence, a survivor of trauma might remember the feeling of fear very vividly, but struggle to put into words the specific details of an event. The prefrontal cortex, which usually calms the amygdala down, also stays underdeveloped, leaving the alarm system in charge (McEwen, 1999).
Social Memory & Hostile Attribution Bias
This rewiring of the memory system creates a specific type of cognitive efficiency that is tailored for high risk environments. In a dangerous home, the cost of missing a cue of a threat, such as the frown of a parent, could mean physical harm. On the other hand, the cost of missing a friendly cue is relatively minor. While reacting to a neutral cue in the office seems counterintuitive in adulthood, the brain uses a biological belief of “better safe than sorry.” It sacrifices the ability to distinguish between a busy and angry nod to avoid missing a potentially threatening one.
Research shows that children with trauma are significantly faster at identifying anger in facial expressions than other children, but they are much slower to recognize happiness (Pollak & Tolley-Schell, 2003). They may exhibit a hostile attribution bias, whereby they tend to interpret ambiguous social information as threatening. While this may have been life-saving in childhood, it can become a liability in adulthood. This hyper-vigilant mindset may follow the individual into the workplace or relationships, causing them to see an enemy where there is only a friend or tired manager.
Memories That Travel
While trauma can have a large impact, it is important to be aware that some individuals are more biologically or environmentally susceptible to these effects than others. Previously it was believed that the “nature vs. nurture” debate was 50/50, but the study of epigenetics has made the debate more complicated and controversial. Trauma can alter the expression of genes associated with the stress response, leading to constant activation of the system (Yehuda & Lehrner, 2018). These changes don’t recode our DNA, but they do affect the magnitude of our stress response.
Additionally, there is the concept of intergenerational memory, biological settings that may be passed down through generations. If the stress system of a mother is calibrated to a high-threat environment, it can change the chemical environment of the womb, potentially pre-calibrating the child’s brain to have that same sensitivity and survival instinct (Del Giudice et al., 2011). Although this adaptation may be beneficial in a dangerous world, it can become maladaptive if the child is born into a safe environment. This is a lifespan cycle that requires more than a simple solution, but rather a deep understanding of the biological narrative of the family.
Clinical Implications
If we only treat symptoms, we ignore the underlying issue. We need to learn to treat the memory architecture itself. Trauma can persist throughout an individual’s lifetime and interrupt other aspects of their well-being until it is resolved.
This is where therapies like Eye Movement Desensitization and Reprocessing (EMDR) or Cognitive Processing Therapy (CPT) may be relevant. They are biological interventions, designed to re-couple the amygdala and hippocampus by helping the brain process and consolidate survival memories into less reactive hippocampal records (Pagani et al., 2012).
Conclusion
It is easy to look at the data on ACEs and feel a sense of biological determinism—that if your early life was hard, your brain may be too vulnerable. However, an enormously positive aspect of the human brain is its ability of neuroplasticity. The same calibration that allowed a child to survive a broken home is proof of the brain’s amazing ability to adapt and respond positively to therapies. For example, research shows that 84% to 90% of single-trauma victims no longer have PTSD after only three 90 minute EMDR sessions (Shapiro, 2014). For CPT, 70% to 80% of patients see a significant reduction in symptoms (Mavranezouli, et al., 2020). These therapies are not merely talking cures, but are actually biological tools that help the brain reclassify past experiences as nonpresent or nonthreatening.
If the brain can be calibrated by trauma, it can also be re-calibrated by safety, consistency, and targeted interventions. The job of physicians is not just to heal the body in the present moment. They must be memory architects, helping patients dismantle biological lenses of their past so they can finally see the world, and themselves, clearly.
References
Del Giudice, M., Ellis, B. J., & Shirtcliff, E. A. (2011). The Adaptive Calibration Model of Stress Responsivity. Neuroscience and Biobehavioral Reviews, 35(7), 1562–1592. https://doi.org/10.1016/j.neubiorev.2010.11.007
Felitti, V. J., Anda, R. F., Nordenberg, D., Williamson, D. F., Spitz, A. M., Edwards, V., Koss, M. P., & Marks, J. S. (1998). Relationship of childhood abuse and household dysfunction to many of the leading causes of death in adults. The Adverse Childhood Experiences (ACE) Study. American Journal of Preventive Medicine, 14(4), 245–258. https://doi.org/10.1016/s0749-3797(98)00017-8
Giotakos, O. (2020). Neurobiology of emotional trauma. Psychiatrike = Psychiatriki, 31(2), 162–171. https://doi.org/10.22365/jpsych.2020.312.162
Mavranezouli, I., Mayo-Wilson, E., Dias, S., Kessler, D., Rivers, P., & Pilling, S. (2020). Psychological treatments for post-traumatic stress disorder in adults: A network meta-analysis. Psychological Medicine, 50(4), 542–555. https://doi.org/10.1017/s0033291720000070
McEwen, B. S. (1999). Stress and hippocampal plasticity. Annual Review of Neuroscience, 22(1), 105–122, https://doi.org/10.1146/annurev.neuro.22.1.105
Pagani, M., Di Lorenzo, G., Verardo, A. R., Nicolais, G., Monaco, L., Lauretti, G., Russo, R., Niolu, C., Ammaniti, M., Fernandez, I., & Siracusano, A. (2012). Neurobiological correlates of EMDR monitoring – an EEG study. PloS one, 7(9), e45753. https://doi.org/10.1371/journal.pone.0045753
Pollak, S. D., & Tolley-Schell, S. A. (2003). Selective attention to facial emotion in physically abused children. Journal of Abnormal Psychology, 112(3), 323–338. https://doi.org/10.1037/0021-843x.112.3.323
Shapiro, F. (2014). The role of Eye Movement Desensitization and Reprocessing (EMDR) therapy in medicine. The Permanente Journal, 18(1), 71–77. https://doi.org/10.7812/TPP/13-098
Teicher, M. H., & Samson, J. A. (2013). Childhood maltreatment and psychopathology: A case for ecophenotypic variants as clinically and neurobiologically distinct subtypes. The American Journal of Psychiatry, 170(10), 1114–1133. https://doi.org/10.1176/appi.ajp.2013.12070957
Yehuda, R., & Lehrner, A. (2018). Intergenerational transmission of trauma effects: putative role of epigenetic mechanisms. World Psychiatry : Official Journal of the World Psychiatric Association (WPA), 17(3), 243–257. https://doi.org/10.1002/wps.20568