Tonic Immobility and the Defense of Those Accused of Title Ix Sexual Assault

What is Tonic Immobility?

Tonic Immobility is a term used to describe a state of apparent involuntary immobility or paralysis, observed in certain animals. In certain species of sharks, it is speculated that it is associated with mating.

With other animals, it may occur in response to a predatory threat (think of an opossum “playing dead” or a rabbit “freezing” in the presence of a predator to blend in with the environment to avoid detection).

Some scientists believe Tonic Immobility is a response that some humans exhibit when faced with a sexual assault. Other scientists do not believe that Tonic Immobility exists in humans. Still others, due to the lack of scientific testing to study the theory of Tonic Immobility in humans (you cannot ethically place humans in a situation of such profound stress to test the theory) believe it to be an unsettled, and thus, unreliable theory. Here is how one psychologist, with decades of experience in the psychological effects of trauma, described it:

“The theory of Tonic Immobility as a phenomenon in humans is theoretical and is not accepted in the scientific community. The evidence that Tonic Immobility exists in humans is completely anecdotal. There is no consensus that this happens in humans.”

The phenomenon, and its applicability to human victims of sexual assault, is, I suppose, a subject of speculation and debate. But that’s not how it’s treated on many college campuses in connection with Title IX sexual assault investigations.


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Hidden from the view and understanding of most accused students and their advisors, the concept of Tonic Immobility is quietly taught as a settled fact to persons involved in the implementation of many schools’ Title IX grievance procedures. This includes Title IX Coordinators, persons who receive complaints, investigators, and adjudicators. The concept of Tonic Immobility is taught as part of a “training” process that seeks to detail “the effects of trauma, including neurobiological change” upon the victims of sexual assault.

The quoted language, comes from a since withdrawn 2014 Obama era Title IX Guidance issued by the United States Department of Education’s Office for Civil Rights (OCR) entitled “Questions and Answers on Title IX and Sexual Violence” (see Section J-3, Page 40) that instructed schools to educate the pertinent Title IX employees on these “neurobiological” concepts. So, what does the “neurobiology” of trauma entail? In an excellent article for The Atlantic entitled “The Bad Science Behind Campus Response to Sexual Assault”, author Emily Yoffe describes it as such:

“It generally goes like this: People facing sexual assault become terrified, triggering a potent cascade of neurotransmitters and stress hormones. This chemical flood impairs the prefrontal cortex of the brain, impeding victims’ capacity for rational thought, and interferes with their memory. They may have significant trouble recalling their assault or describing it coherently or chronologically. The fear of imminent death may further illicit an extended catatonic state known as “Tonic Immobility”, rendering them powerless to speak or move – they feel “frozen”. (Id., September 8, 2017).

Unfortunately, this scientifically unproven theory of Tonic Immobility, despite the withdrawal of the aforementioned 2014 OCR Guidance, is now firmly implanted in the policies and practices of institutions across the country. Consider a 170 page document entitled “The Blueprint for Campus Police: Responding to Sexual Assault”, published in February 2016 under the auspices of the impressive sounding Institute on Domestic Violence and Sexual Assault, School of Social Work, University of Texas at Austin. This document, split into 15 discrete sections, list its purpose as follows:

“The purpose of The Blueprint for Campus Police: Responding to Sexual Assault is to fill gaps in current research and identify best practices in campus police response to sexual assault…The Blueprint is empirically driven through in-depth interviews, field observations, and a thorough review of the policies and practices pertaining to CSA [Campus Sexual Assault]. This resource is intended to serve as a Guide or Tool Kit for police at all levels…in response to sexual assault crimes with the implementation of victim centered and trauma informed approaches. In this way, The Blueprint replaces tradition with science.” (emphasis in original).

In Section 9 of “The Blueprint”, entitled “Tool Kit for Campus Police: Briefing Sheets”, the following information is conveyed as reliable scientific fact:

Sexual assault is a trauma which causes the brain to detect a threat. The brain releases hormones that flood the body activating behavioral defense strategies such as fight, flight, freeze or appease”. (Id. at 84).

. . .

“When people are stressed, they revert to a more primitive level of functioning, which represents an uncontrollable (autonomic) response.” (Id. at 86).

. . .

“Women may be more likely to try to appease an assailant or freeze, than use a “fight or flight” response.” (Id.)

. . .

“The freeze response is called “tonic immobility” or sexual assault induced paralysis and it is caused by a flood of hormones that activate in response to a threat. It may be more common in victims that were previously assaulted.” (Id.)

. . .

“They are literally “scared stiff” or “play opossum”, not a pretense, but rather an evolutionary survival tactic.” (Id.).

. . .

Here are some corresponding “Promoting Best Law Enforcement Practices” tips:

“Don’t ask a lot of questions at first since they may interrupt the flow of the victim’s narrative.” (Id. at 85).

. . .

“Understand because of the trauma, victims’ brains are better at remembering sensory information over details. Ask victims about what they remember hearing, tasting, touching, seeing, and smelling over “who, what, and where” questions to prompt memory recall.”(Id.)

. . .

“Understand that the freeze response does not mean consent, but instead is the body’s automatic neurological response to trauma, threat and fear.” (Id. at 86).

. . .

“Explain to victims that tonic immobility is a normal reaction to fear and trauma, in order to counter self-blaming and guilt that they ‘did not fight back’.” (Id.).

. . .

The Blueprint is an example of proposed training materials for campus assault investigators issued from a highly respected institution, presenting disputed scientific concepts as reliable, proven and the latest in accepted scientific research. Going further, The Blueprint encourages investigators to disregard traditional and proven investigative methods in favor of new methods fashioned around an uncritical adherence to these questioned “scientific” conclusions, or, as The Blueprint boldly explains:

“…the Blueprint replaces tradition with science.” (Id. at page 7).

. . .

Along with the lack of reliability of the conclusions and the failure to honestly address the fact that the “science” presented is not settled, the worst thing about these types of training materials is that they are closely held by the schools and not shared with the accused student or their advisors.

In addition, in the hands of victim advocates and counselors, well intentioned as they may be, alleged victims of sexual abuse can be unintentionally coached into reporting such phenomena as Tonic Immobility. These reported “symptoms” will then often be treated by “trained” Title IX investigators and adjudicators as evidence of sexual assault. Meanwhile, the accused student stands in the dark.

A student accused of sexual assault should be aware of these concepts. Training materials should be demanded (though they are unlikely to be produced), a defense challenging these unproven concepts should be attempted, even if it is ultimately rejected. In the end, perhaps a future court of law will find the training materials utilized and often concealed by the institution a worthy subject of serious scrutiny.


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