R. v. D.D., 2022 ONCA 786, November 17, 2022, at paragraphs 4 to 6, and 8:
In R. v. W. (R.),  2 S.C.R. 122, it was affirmed that the evidence of children must be approached on a common sense basis bearing in mind their mental development, understanding and ability to communicate. “Since children may experience the world differently from adults, it is hardly surprising that details important to adults, like time and place, may be missing from their recollection”: R. v. W. (R)., at para. 25. By way of illustration, the inability of the child complainant in R. v. W. (R.) to accurately describe the location of bedrooms in a house, a peripheral matter, was not significant to her credibility or reliability, since a child may not attend to such details: R. v. W. (R.), at para. 30.
Even when adults testify about events that allegedly occurred when they were children, such considerations remain relevant. This is logical. If a witness would not likely have noted the thing as a child, their failure to relate that thing years later while testifying as an adult cannot meaningfully unsettle the credibility or reliability of their evidence. Therefore, “the presence of inconsistencies, particularly as to peripheral matters such as time and location, should be considered in the context of the age of the witness at the time of the events to which she is testifying” (emphasis added): R. v. W. (R.), at para. 27.
However, “[in] general, where an adult is testifying as to events which occurred when she was a child, her credibility should be assessed according to criteria applicable to her as an adult witness”: R. v. W. (R.), at para. 27. The trial judge cited this principle correctly but misapplied it.
… To be clear, there can be no issue taken with a trial judge finding that details provided by an adult witness about a childhood experience are the kinds of things a child would remember, or that details recounted by the adult witness provide plausibility or coherence to the account. But what a trial judge cannot do is infer that such details, being provided by an adult witness, must be true because a child would not have the intelligence or experience to concoct those details.