Evaluating the Credibility of Statements Given by Persons with Intellectual Disability

What is it about?

The objective of this study was to analyze the features that distinguish statements given by actual and simulated victims with mild to moderate intellectual disability, using the credibility analysis procedure known as Reality Monitoring (RM). Two evaluators trained in credibility analysis procedures using content criteria evaluated 13 true statements and 16 false statements. The results obtained show that there is little difference between the two types of statements when analyzed on the basis of content criteria using the RM procedure. The only criteria that proved to be significant for discriminating between the two types of statements were the amount of details and the length of spontaneous statements obtained through free recall. None of the phenomenological characteristics studied turned out to be significant for discriminating between actual and simulated victims. Graphic representation using high-dimensional visualization (HDV) with all criteria taken into consideration shows that the two types of statements are quite heterogeneous. Cluster analysis can group cases with a 68.75% chance of accuracy.

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Why is it important?

Results are contrary to those found in the previous research, which was conducted with developmentally normal persons (Manzanero, et al., 2016), where the dispersion of points on the graph was observed to be greater for statements given by participants assuming the perspective of false protagonist than for those assuming the actual perspective. In that study, in contrast to this one, the two types of statements could be distinguished with a 94.3% chance of accuracy. At any rate, this difference in the results could be accounted for by differences between the two studies in terms of not only the participants but also the events—for an actual event was used for the present study, but a filmed event and a different type of fabrication was used for the study with participants who did not have ID. It would be advisable to conduct further research with different events and different types of fabrication so that the results could be generalized.