• About
    • Login
    View Item 
    •   Institutional Repository Home
    • Electronic Theses and Dissertations
    • Electronic Theses and Dissertations
    • View Item
    •   Institutional Repository Home
    • Electronic Theses and Dissertations
    • Electronic Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of Institutional RepositoryCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister

    Effects of Legal Instructions on Behavioral and Neural Mechanisms of Decision-Making

    Hartsough, Lauren
    0000-0002-5182-5083
    : http://hdl.handle.net/1803/16395
    : 2020-11-18

    Abstract

    A fundamental question in decision-making is how instructions can be used to influence behavior. Nowhere is this question more important than in the legal system, in which the fate and lives of individuals are in the balance. In the United States, jurors are frequently instructed to apply poorly defined and varied decision thresholds (burdens of proof), as well as instructions to disregard inadmissible evidence. For civil trials, a preponderance of evidence (PoE) is set as the decision threshold, while criminal trials require the more stringent threshold of beyond a reasonable doubt (BaRD). It is unclear, however, how decision threshold and disregard instructions are applied by laypeople and how they compare to participants’ intuitive decisions. To evaluate burden of proof instructions, here we applied quantitative, psychometric analyses to assess and compare decision thresholds across instruction-type in both legal and non-legal contexts. We found a consistent pattern across all legal scenarios, non-legal scenarios, and psychophysical tasks: As expected, naive individuals interpreted PoE less stringently than BaRD, but surprisingly, they interpreted PoE more conservatively than their own intuitive belief (IB) and the legally prescribed threshold. Decision thresholds were also more stringent for legal than any non-legal contexts. Follow-up studies addressed why laypeople's PoE standard is interpreted more stringently than expected, and why adjudication in the legal domain is consistently more conservative than any other domains of decision-making tested. We also examined how domain expertise affected this pattern of results. Furthermore, to understand the application of disregard instructions we built on an existing neuroimaging paradigm to evaluate the brain mechanisms involved in assessing biasing character evidence and admissibility instructions using fMRI. We found that an instruction allowing individuals to consider evidence increased punishment independent of character evidence, and identified several prefrontal regions associated with individual differences in the application of this instruction. Taken together, our findings suggest that legal instructions can influence decisions in ways not intended or accounted for by the law. This may call for a re-assessment of the intended outcomes of legal standards – particularly PoE – as well as the potentially biasing effect of admissibility rulings.
    Show full item record

    Files in this item

    Icon
    Name:
    HARTSOUGH-DISSERTATION-2020.pdf
    Size:
    4.616Mb
    Format:
    PDF
    View/Open
    Name:
    Dissertation_Supplement.docx
    Size:
    20.16Mb
    Format:
    Microsoft Word 2007
    View/Open

    This item appears in the following collection(s):

    • Electronic Theses and Dissertations

    Connect with Vanderbilt Libraries

    Your Vanderbilt

    • Alumni
    • Current Students
    • Faculty & Staff
    • International Students
    • Media
    • Parents & Family
    • Prospective Students
    • Researchers
    • Sports Fans
    • Visitors & Neighbors

    Support the Jean and Alexander Heard Libraries

    Support the Library...Give Now

    Gifts to the Libraries support the learning and research needs of the entire Vanderbilt community. Learn more about giving to the Libraries.

    Become a Friend of the Libraries

    Quick Links

    • Hours
    • About
    • Employment
    • Staff Directory
    • Accessibility Services
    • Contact
    • Vanderbilt Home
    • Privacy Policy