False Memory Cases & the Expert Witness

The framework for admitting expert evidence

In R. v. Abbey, 2009 ONCA 624 (CanLII), Doherty J.A. charted a two-step process for determining the admissibility of expert opinion evidence.

Step 1

The four criteria from R. v. Mohan 1994 CanLII 80 (SCC), [1994] 2 S.C.R. 9 were absorbed under the first step:

(i)           relevance,

(ii)         necessity in assisting the trier of fact,

(iii)        absence of an exclusionary rule (other than the opinion rule), and

(iv)         a properly qualified expert.

The party proffering the opinion must demonstrate on a balance of probabilities that these preconditions to admissibility exist before proceeding to the second step.

Step 2

Provided the applicant satisfies the court as to the existence of the four Mohan criteria, then the court will go on to consider whether the proposed opinion evidence is sufficiently beneficial to the trial process to warrant admission, despite the “potential harm to the trial process that may flow from the admission of the expert evidence”: Abbey, at para. 76.

Step two is often referred to as the “gatekeeper” component of the expert evidence admissibility inquiry. The proposed evidence must meet all of these preconditions before being admitted for consideration by the trier of fact.

[For an excellent synthesis of the law with respect to the admissibility of expert opinion evidence generally, see R. v. M.C., 2014 ONCA 611 (CanLII), per Justice Watt].

CASES

R. v. J.F., 2015 ONSC 3067

While the trial court decides issues of credibility and reliability virtually every day, an understanding of the psychology of memory-including false memories versus true ones—is outside its cognizance. The opinion of the expert witness is necessary to allow the court to appreciate whether the statement of a witness as to what happened was the product of false memories.

R. v. Hackett, 2004 ONSC

The witness, a psychiatrist with a particular expertise in memory, was qualified to give psychiatric evidence, including evidence of false memory syndrome.  On the basis of the expert’s voir dire testimony, the trial judge concluded that false memory syndrome is not a particular area of psychiatric expertise but is “part and parcel” of psychiatry.  Expert permitted to testify on how acquired or false memories are created.

See R. v. Hackett, 2006 CanLII 10949 (ON CA).

R v B.W.W, 2017 ONSC 985 (CanLII)

The applicant did not meet the threshold test for admissibility.  Among other reasons, the court found that the admissibility of the proposed expert’s evidence failed on the necessity requirement--to “assist the trier of fact by providing special knowledge that the ordinary person would not know”.  The proposed evidence was well within the experience of judges and, in fact, all triers of fact.