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Understanding the impact of trauma on witness testimony

We need to challenge assumptions about our approach to assessing the credibility and reliability of witnesses in our justice system.

Witness trauma

Back when he was teaching evidence law to young lawyers in training, Benjamin Perrin liked to start the semester by telling his students how the justice system used to get it wrong.

“We used to consider it circumstantial evidence of guilt if the accused in a murder trial failed to cry at the victim’s funeral,” said Perrin, a former legal adviser to Prime Minister Stephen Harper, now a professor of law at the University of British Columbia and author of Indictment: The Criminal Justice System on Trial.

“The point is that we can look back and be shocked about what we used to consider evidence of honesty or truthfulness, but we can’t assume we’re getting it 100 right now.”

Trials are built on witness testimony and other forms of evidence. Often — and especially in cases of sexual assault — the hard evidence is slight and the trial comes down to witnesses’ conflicting versions of events.

It’s the “Rashomon problem” and Canada’s justice system gives judges and juries wide latitude to address it by assessing the consistency of witnesses’ testimony and their behaviour on the stand. In the case of witnesses who have experienced trauma, Perrin and others believe the system gets it wrong far more often than anyone likes to admit.

“The effect of trauma on memory is problematic for the justice system because it operates in a way that defines the ‘common sense’ upon which judges and juries are expected to rely,” said Thor Paulson, an articling student at Fasken. He recently co-wrote a paper (published in the Canadian Bar Review) with Perrin and two medical professionals — U of T professor of psychiatry Dr. Robert G. Maunder and Dr. Robert T. Muller, professor of clinical psychology at York University — about how courts treat testimony from trauma survivors.

“The way trauma affects the brain has been well studied and it’s predictable. Unfortunately, it runs counter to a lot of our notions of what makes a good witness.”

Take the question of consistency. A competent defence lawyer knows how to spot inconsistencies in testimony and use them to undermine the case against their client. Judges are expected to take those inconsistencies into account in their assessment of a witness’s credibility.

None of this is especially controversial. The Supreme Court of Canada considers credibility assessments to be the product “of the judge or jury’s view of the diverse ingredients it has perceived at trial, combined with experience, logic and an intuitive sense of the matter.” It’s an art, not a science, one the justice system sees as part of the common experience of the average judge or juror — no outside expertise necessary.

All of which would be fine if trauma survivors behaved on the stand the way the average person expects them to. But trauma scrambles the way the brain retains and recalls memories, said Dr. Maunder — which leads to what he calls “narrative incoherence.”

“It affects the way people organize stories of their life,” he said via email. “It makes it hard for the person telling their story to keep their audience (in this case judges and juries) ‘in mind,’ meaning it is hard to tell the story the way that makes it easy to understand and believe — with clear chronologies, and well identified characters and reflection on the parts that need more detail or clearer description, and emotions expressed that match the content of the story.

“Being able to tell stories well is important for telling true stories about one’s life and having them understood and believed. In my world (medicine), it is how a person explains their illness and gets help. In a courtroom, it is how their story is taken to be credible.”

Trauma also distorts how its victims display emotion when describing their experiences, said Dr. Maunder.

 “Emotionally, people who have experienced trauma often seem either overly emotional or under-emotional when describing themselves and events in their life,” he wrote. “Being overly emotional results from a failure of a person’s ability to regulate emotion, which can be caused or amplified by trauma.

 “You can think of being underly emotional as a defence mechanism — sticking to ‘just the facts’ in order not to be overwhelmed. Judges and juries may think a person is not credible because they don’t seem upset when talking about upsetting things, or they may be so emotional that the facts they are conveying are hard to understand or are not believed.”

 It all points to a fundamental flaw in how the justice system handles witness testimony, said Perrin — one that almost certainly has led to miscarriages of justice.

 “The assessment of the credibility and reliability of witnesses is a foundational concept of our adversarial justice system,” he said. “If the assumptions it’s based on are flawed, it calls into question the entire proceeding.

“The stakes could not be higher. Everything we know about this suggests that judges and juries have gotten it wrong.”

One obvious approach would be for trials to hear from medical experts on trauma’s effects on recall and emotional display. But because the jurisprudence says evaluating witness credibility is something the average person can do, courts might frown on attempts to bring in outside expertise.

 “Courts don’t permit expert witness testimony on matters of common experience — you don’t bring in an expert to tell you whether it’s raining outside,” said Perrin. “But an understanding of the science of trauma is crucial to assessing the testimony of traumatized witnesses — whether they are the complainant, accused or third parties.

“That sets up a presumption that such trials aren’t likely to hear from experts on trauma.”

Perrin, Paulson, Maunder and Muller are calling for what they call a “trauma-informed” approach to witness testimony — one that considers trauma’s effects on memory and emotional display while avoiding “circular reasoning” (assuming, for example, that signs of trauma in testimony prove the trauma took place).

“This isn’t going to be solved through legislation and I don’t think you could get Parliament interested in it anyway,” said Perrin. “The more direct and efficient route would be for the Supreme Court to issue a decision that reflects how evaluations of the demeanor and consistency of trauma victims’ testimony should be approached. In the United Kingdom, there are model jury instructions that have begun to address this deficiency.”

 He said their hope is that their article, “peer-reviewed and in a major journal,” could be a “catalyst.”

“It can be cited in court submissions in support of bringing in expert testimony,” he said. “Change can happen at the lower court levels very quickly.”