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…