Why are victims of sexual assault so often not believed? A large percentage of the disbelief may be linked to the behavioural patterns of victims themselves, which can vary widely from case to case and often include behaviours of which the average police officer or caregiver would be skeptical. To understand these patterns, it is helpful to look at how the brain and body respond to stress and trauma, such as that experienced during sexual violence. A relatively new area of the literature on human response to trauma, particularly the trauma experienced during sexual violence, is that of “tonic immobility.” Tonic immobility is defined as self-paralysis, or as the inability to move even when not forcibly restrained. It has long been studied in non-human animals as the “freeze” response to extreme stress. Recently, it has been observed in the laboratory as a stress response in humans, as well. This finding explains the reaction of many victims of sexual violence, who report that they felt like they could not escape, even when no weapon was present.
Additionally, due to an entire cascade of hormonal changes, which includes oxytocin and opiates, associated with pain management, adrenaline, commonly associated with “fight or flight,” and cortisol, functional connectivity between different areas of the brain is affected. In particular, this situation affects pathways important for memory formation, which means that an individual generally will remember the traumatic event itself (unless alcohol or drugs are present in the system), these memories will feel fragmented, and may take time to piece together in a way that makes narrative sense. Behavioural patterns in individuals who have experienced sexual violence mirror those seen in other traumatized populations, like combat veterans. This pattern of symptoms, known as post-traumatic stress disorder, or PTSD, can include emotional numbness, intrusive memories of the traumatic event, and hyper-arousal (increased awareness of one’s surroundings, or constantly being “on guard”).
Research shows that the majority of individuals who experience sexual assault demonstrate at least some of these symptoms of PTSD immediately after the assault and through the two weeks following the assault. Nine months after the assault, 30% of the individuals still reported this pattern of symptoms. Overall, it is estimated that nearly one-third of all victims of sexual assault will develop PTSD at some point in their lives.
These findings are complicated by the fact that the response of any given person to trauma can look extremely different, based on previous life experiences and health factors. Research has found that cognitive variables, such as perceived negative responses of other people and poor coping strategies, were significantly linked both to development of PTSD and severity of PTSD. In another study, lower cortisol levels as measured in the emergency room have been related to increased risk for the development of PTSD. In other words, a maladaptive version of nature/nurture is involved in individuals’ responses to trauma. As with many questions related to health, it is difficult to pinpoint the cause: existing neurobiological and psycho-social risk factors, such as mental illness, can contribute to the development of PTSD, and PTSD can lead to other health problems. There is no hard and fast rule of victimology: every individual who experiences sexual violence will respond differently.
Therefore, the police who are unable to believe a victim’s story are likely misinterpreting the discrepancies in the story as lies, rather than as the brain’s response to extreme trauma. Best practices now suggest that police officers wait at least two sleep cycles, generally 48 hours, before interviewing a victim of sexual violence. Additionally, the interview should be handled in a victim-centred manner, not as an interrogation.
Adapted from Cognitive Neuroscience Society: The Neuroscience of Trauma from Sexual Assault