Mock Juror Understanding of Complex Testimony: the Flynn Effect in Atkins Cases

Thumbnail Image
Journal Title
Journal ISSN
Volume Title
University of Alabama Libraries

In 2002, the Supreme Court ruled that individuals with intellectual disability (ID) could not be sentenced to death (Atkins vs. Virginia). Since this decision, triers-of-fact have been making determinations as to whether a defendant meets the diagnostic criteria for ID. The current study evaluated whether an expert witness' credentials and the complexity of their testimony would influence mock jurors' diagnostic determinations. Undergraduate students were exposed to testimony on the Flynn effect (a statistical phenomenon relevant to IQ scores and ID determinations) that varied in complexity. Credentials of the testifying defense expert witness were also manipulated. There was no significant effect of complexity level of the testimony, though scores on a post-hearing comprehension test suggested participants overall struggled to understand the Flynn effect. Testimony from a defense expert with more prestigious credentials was more persuasive, with participants being more likely to agree that the claimant meets diagnostic criteria for ID. In addition, participants' need for cognition (NFC) and other related attitudes were measured. Participants higher in NFC were more likely to scrutinize application of the Flynn effect and determine the claimant did not meet criteria for ID. Implications of these findings for legal actors in Atkins cases and future directions for researchers are discussed.

Electronic Thesis or Dissertation
dual processing, Flynn effect, intellectual disability, mock juror, need for cognition