Test for testimonial competence of adults with mental disabilities

R. v. D.A.I., 2012 SCC 5 deals with the requirements of s. 16 of the Canada Evidence Act for the testimonial competence of persons of 14 years of age or older (adults) with mental disabilities. While dealing with the federal act only, the analysis of course has suasive influence when dealing with provincial legislation.

 

Section 16(3) imposes two requirements for the testimonial competence of an adult with mental disabilities:  (1) the ability to communicate the evidence; and (2) a promise to tell the truth.  It is unnecessary and indeed undesirable to conduct abstract inquiries into whether the witness understands the difference between truth and falsity, the obligation to give true evidence in court, and what makes a promise binding.  The plain words of s. 16(3) focus on the concrete acts of communicating and promising.  Judges should not add other elements to the dual requirements imposed by s. 16(3).  This approach does not transform the promise into an empty gesture.  Adults with mental disabilities may have a practical understanding of the difference between the truth and a lie and know they should tell the truth without being able to explain what telling the truth means in abstract terms.  When such a witness promises to tell the truth, the seriousness of the occasion and the need to say what really happened is reinforced.

 

When applying s. 16(3) in the context of the Canada Evidence Act, eight considerations are appropriate.  First, the voir dire on the competence of a proposed witness is an independent inquiry: it may not be combined with a voir dire on other issues.  Second, the voir dire should be brief, but not hasty.  It is preferable to hear all available relevant evidence that can be reasonably considered before preventing a witness to testify.  Third, the primary source of evidence for a witness’s competence is the witness herself.  Her examination should be permitted.  Questioning an adult with mental disabilities requires consideration and accommodation for her particular needs; questions should be phrased patiently in a clear, simple manner.  Fourth, persons familiar with the proposed witness in her everyday situation understand her best.  They may be called as fact witnesses to provide evidence on her development.  Fifth, expert evidence may be adduced if it meets the criteria for admissibility, but preference should always be given to expert witnesses who have had personal and regular contact with the proposed witness.  Sixth, the trial judge must make two inquiries during the voir dire on competence: (a) does the proposed witness understand the nature of an oath or affirmation, and (b) can she communicate the evidence?  Seventh, the second inquiry into the witness’s ability to communicate the evidence requires the trial judge to explore in a general way whether she can relate concrete events by understanding and responding to questions.  It may be useful to ask if she can differentiate between true and false everyday factual statements.  Finally, the witness testifies under oath or affirmation if she passes both parts of the test, and on promising to tell the truth if she passes the second part only.

 

The Court holds:

 

Summary of the Section 16(3) Test

 

[74]                          To recap, s. 16(3) of the Canada Evidence Act imposes two conditions for the testimonial competence of adults with mental disabilities:

(1)        the witness must be able to communicate the evidence; and

 

(2)        the witness must promise to tell the truth.

Inquiries into the witness’ understanding of the nature of the obligation this promise imposes are neither necessary nor appropriate.  It is appropriate to question the witness on her ability to tell the truth in concrete factual circumstances, in order to determine if she can communicate the evidence.  It is also appropriate to ask the witness whether she in fact promises to tell the truth.  However, s. 16(3) does not require that an adult with mental disabilities demonstrate an understanding of the nature of the truth in abstracto, or an appreciation of the moral and religious concepts associated with truth telling.

[75]                          The following observations may be useful when applying s. 16(3) in the context of s. 16 of the Canada Evidence Act.

[76]                          First, the voir dire on the competence of a proposed witness is an independent inquiry: it may not be combined with a voir dire on other issues, such as the admissibility of the proposed witness’s out-of-court statements.

[77]                          Second, although the voir dire should be brief, it is preferable to hear all available relevant evidence that can be reasonably considered before preventing a witness to testify.  A witness should not be found incompetent too hastily.

[78]                          Third, the primary source of evidence for a witness’s competence is the witness herself.  Her examination should be permitted.  Questioning an adult with mental disabilities requires consideration and accommodation for her particular needs; questions should be phrased patiently in a clear, simple manner.

[79]                          Fourth, the members of the proposed witness’s surrounding who are personally familiar with her are those who best understand her everyday situation.  They may be called as fact witnesses to provide evidence on her development.

[80]                          Fifth, expert evidence may be adduced if it meets the criteria for admissibility, but preference should always be given to expert witnesses who have had personal and regular contact with the proposed witness.

[81]                          Sixth, the trial judge must make two inquiries during the voir dire on competence: (a) does the proposed witness understand the nature of an oath or affirmation, and (b) can she communicate the evidence?

[82]                          Seventh, the second inquiry into the witness’s ability to communicate the evidence requires the trial judge to explore in a general way whether she can relate concrete events by understanding and responding to questions.  It may be useful to ask if she can differentiate between true and false everyday factual statements.

[83]                          Finally, the witness testifies under oath or affirmation if she passes both parts of the test, and on promising to tell the truth if she passes the second part only.