Traumatic Stress, Memory, and the Investigative Process

Traumatic stress impacts memory. We tend to consider this when we investigate violent crimes such as sexual assault. We have evolved in our interviewing process with victims through techniques of trauma-informed interviewing, cognitive interviewing, and forensic interviewing. This growth has allowed us to better understand the considerations involved in memory, recall, and perspective.

We used to ask victims of sexual assaults horrifying questions: What were you wearing? Did you say no? Did you fight back…no? Why not? Tell me what he looked like. You can't? Why can't you describe him to me? We caught the guy who raped you…why didn't you tell me he had tattoos all over his face?

What changed?

We did. We were not serving victims and survivors in the best manner possible. We learned, grew, and evolved in our craft to provide grounded and compassionate care within the investigative process.

What did we learn?

We learned that information gathered during an interview can be compromised by flawed interviewing, questioning, or interrogation practices.¹ Interviews that are structured chronologically, in a directive manner, comprised primarily of close ended questions, and conducted by multiple individuals do not fall within best practices. We learned that leading questions raise concerns in almost any interview as they tend to suggest their own answer. Interviewers and investigators may experience "leading question bias" where the interviewer directs the question toward the answer they want or what they subjectively think to be true.

We learned that when an individual experiences an overwhelming or traumatic event, there should be protocols in place to protect the individual from additional trauma during the interview process. Trauma-informed interviewing allows for a non-threatening, conversational approach that avoids interrogation methods.² Cognitive interviewing is structured to enhance memory recall and minimize memory confabulation. There is a misperception in law enforcement investigations that an individual with a lack of linear memory is deliberately lying. We have now learned that a lack of linear memory can be a sign of trauma.

We learned a person's frame of mind and amount of sleep impact memory consolidation and recall. Sleep is essential for memory formation and consolidation.³ Unconsolidated memory is fragile and can be disrupted by various types of interference. Two sleep cycles may be necessary for memory consolidation to occur.⁴ During an overwhelming event that activates an acute stress response, there is a loss or reduction in the functioning of the prefrontal cortex of the brain. This impacts our executive function, or what would be basic reasoning, weighing of options for decision-making, emotional regulation, impulse control, access to working memory, and memory consolidation.

After a traumatic experience, intentional and unintentional remembering can introduce new details that, over time, assimilate into a person's memory for the event.⁵ Studies show that individuals can experience events that they have not in reality experienced.⁶ This is known as confabulation.

Confabulation is a type of memory error in which gaps in a person's memory are unconsciously filled with fabricated, misinterpreted, or distorted information.⁷ The most common type of confabulation is provoked confabulation which occurs when someone creates an untrue story in response to a specific question. It is critical to recognize that there is no deliberate attempt to lie or provide false information.

Memory conformity may present when two people see the same event and discuss it and one person's memory influences what the other person claims to remember.⁸ Memory conformity can occur from a discussion or conversation, reading a review of another person's incident perspective, or from watching a video of the event.

These are just a few of the things we have discovered over the years to better serve victims of violent crime. But my question to you is this: Why are we not bringing these practices to investigations when officers experience critical incidents?

We should all agree from a macro view that critical incidents are traumatic stress events. The difference in how a traumatic event is processed is the micro level of an individual's coping skills, ability to tolerate stressors, and support system (to name just a few).

We have evolved in our support of victims who experience violence, let's continue that evolution to include our officers.

References

1. Gehl, R. & Plecas, D. (2016). Introduction to Criminal Investigation: Processes, Practices and Thinking. New Westminster, BC: Justice Institute of British Columbia.
2. Flores, L. & Phelps, K. (2017). Trauma Informed Interviewing Techniques Best Practices for Working with Trauma Survivors. Biannual Asylum Law Seminar.
3. Klinzing J., Niethard, N., Born, J. (2019). Mechanisms of systems memory consolidation during sleep. Nat Neurosci 2019 Oct;22(10):1598-1610
4. McGaugh J. (2000). Memory-a century of consolidation. Science. 2000 Jan 14;287(5451):248-51. doi: 10.1126/science.287.5451.248. PMID: 10634773
5. Strange, D., & Takarangi, M. K. (2015). Memory distortion for traumatic events: the role of mental imagery. Frontiers in psychiatry, 6, 27. https://doi.org/10.3389/fpsyt.2015.00027
6. British Psychology Society Research Board Working Group (2008). Guidelines on memory and the law: recommendations from the scientific study of human memory. British Psychological Society
7. Triviño M, Ródenas E, Lupiáñez J, Arnedo M (2017). Effectiveness of a neuropsychological treatment for confabulations after brain injury: A clinical trial with theoretical implications. PLoS ONE 12(3): e0173166. https://doi.org/10.1371/journal.pone.0173166
8. Gabbert F, Memon A, Wright DB. Memory conformity: disentangling the steps toward influence during a discussion. Psychon Bull Rev. 2006 Jun;13(3):480-5. doi: 10.3758/bf03193873. PMID: 17048734.