Provisional Assumptions

In courtrooms, the law often asks individuals to ignore information—carefully, purposely—that otherwise feels important. Juries, for example, are often asked to disregard information about a variety of facts, from prior convictions to settlement negotiations. But legal literature and psychology research has shown us that it is difficult for jurors to follow these instructions and cabin their curiosity about different facts in a case. Jurors have difficulty suppressing their thoughts; they rebel against admonitions; they create story-based hypotheses that are resistant to change.

To help align these evidence exclusions with empirical realities, this Article introduces an original tool: a provisional assumption. A provisional assumption would ask jurors not to ignore information but to assume certain information about subjects for which evidence is inadmissible; for instance, to assume that a civil defendant has no insurance against liability or that a criminal defendant has no prior criminal record. Drawing from psychological theories that explain why people rebel against admonitions, such as mental control and reactance, I test provisional assumptions using two experimental studies. Leveraging the context of insurance and its inadmissibility in tort cases, the results suggest that this approach would allow jurors to focus on the facts that matter. Provisional assumptions appear to hold promise as a portable intervention applicable in boardrooms and interview suites as well as courtrooms, and as a model of procedural innovation informed by interdisciplinary research.


In July 1987, Steve Terry was playing catch with his two sons when the ball landed in a tree.[1] When Terry tried to reach for the ball with a pole, he struck an improperly installed power line and was electrocuted, causing him severe injury.[2] Four years later, a jury awarded more than $5 million to Terry, but the utility company, Plateau Electric Cooperative, moved for a mistrial.[3] Its argument: the jury had heard something forbidden.

Plateau believed that Terry’s attorney had improperly prejudiced the jurors by eliciting testimony that mentioned in passing that the utility company owned insurance,[4] and it brought affidavits from three jurors mentioning what other jurors had said: that the utility company’s “insurance carrier would not miss” $5 million,[5] that “the corporation always ‘gets over on the individual and I am not going to let it happen this time,’ ”[6] and that “sometimes ‘you just have to break the law.’ ”[7]

To the appeals court, these statements went beyond the “life experiences”[8] jurors are “encouraged . . . to rely upon”[9] into “an astonishing amount of extraneous prejudicial information.”[10] Even though it might be “common knowledge” that Plateau, as a utility company, had liability insurance,[11] to the judge on appeal, that “argument beg[ged] the question: What would the verdict have been had there been no insurance, with that fact being made known to the jury?”[12]

This Article seeks to unpack that question. Terry’s case is just one illustration of how insurance status can generate assumptions about a party’s ability to pay damages and its responsibility. But such assumptions occur across other subjects of litigation, from car accidents[13] to medical malpractice[14] to corporate indemnification.[15]

By excluding information about a party’s insurance status—or their lack thereof—federal[16] and state[17] rules of evidence, alongside their early common law underpinnings,[18] attempt to reduce bias and confusion among jurors. And in an attempt to make this exclusion effective, courts instruct jurors either to disregard insurance status if it slips out during the trial or to only regard it for a particular purpose.[19] These admonitions rest on the assumptions that jurors can disregard inadmissible information that enters the courtroom, that they can consider a piece of evidence for one purpose but not for others, and that they can prevent speculation about inadmissible information.[20]

Yet, we know these assumptions can be fictive. In other evidentiary situations in which jurors encounter admonitions from a judge, the admonition frequently fails. For instance, notwithstanding instructions to ignore information about a defendant’s criminal record, jurors are more likely to think that defendants with prior convictions are guiltier.[21] Jurors also incorporate information from the news into their deliberative processes, despite the presence of admonitions.[22] This pretrial publicity can lead to harsher treatment of criminal defendants,[23] even if jurors believe they are being unbiased.[24]

Perhaps courts could exert extra effort in “blindfolding,” ensuring that inadmissible information is not mentioned at all, by incentivizing parties to create comprehensive motions in limine that exclude evidence and sanctioning violations of the motion.[25] But even if inadmissible information were to be perfectly hidden or “blindfolded” from jurors, in actuality, jurors might use their everyday stereotypes to construct their narrative of the case, as in Terry v. Plateau Electric Cooperative.[26] They also might speculate about missing information, to the detriment of focusing on the facts at hand.[27] The problem remains: How do we prevent people from their own speculation, if telling them not to consider information—that is, an admonition—might make them more likely to do it?

In this Article, I use the evidentiary limitations on the admissibility of insurance as a springboard to help understand how we might reduce juror speculation and to offer an alternative to jury admonitions. I suggest that courts should consider providing a provisional assumption for jurors, that is, request that jurors assume a particular piece of information when making their determination. I theorize that such provisional assumptions will reduce the inadmissible information’s salience and allow individuals to focus on the facts that courts deem most important.

To investigate whether provisional assumptions could work, I use a pair of survey experiments relating to the admissibility of insurance in trials. The experiments ask mock jurors in an online study to assume that neither the plaintiff nor the defendant has insurance, comparing them to another group of mock jurors who are simply given a standard jury instruction that says generally that insurance should not be considered. I find that those jurors asked to provisionally assume no insurance are less likely to be interested in the plaintiff’s insurance and may award less damages to the plaintiff. And I find potential evidence that these results are robust under uncertainty.

By accounting for the psychology of jury decision-making, the provisional assumption intervention aligns legal theories with human psychology, while yielding several policy-relevant benefits. First, allowing jurors to assume facts about insurance allows them to concentrate on the questions that matter to the law and prevents jurors from making assumptions that might be inconsistent with those of the other jurors or the objectives of the evidentiary rule at hand. Second, a provisional assumption is a solution whose simple implementation generates minimal bias to either party. Third, this procedural innovation is behaviorally informed but does not treat jurors in a patronizing fashion. Providing jurors with a provisional assumption might displace the assumptions they have—and also displace our own assumptions about how jurors behave.

This Article proceeds in three parts. Part I lays out the historical and functional importance of the evidence rules underlying the exclusion of insurance status from jury consideration. It then addresses how courts have dealt with the exclusion in practice. Part I also shows how jury instructions fall short  of eliminating forbidden information by illustrating the disconnect between evidentiary exclusions and empirical realities via classic examples in social psychology and jury studies.

Part II contains two original studies. It imagines what an ideal intervention would look like and introduces the provisional assumption as a psychology-based intervention, consistent with legal intuitions about evidence. It then describes and reports on the results of two original survey experiments that demonstrate the first-ever use of this intervention.

Lastly, Part III explores the implications of these studies for juror decision-making and legal decision-making generally. To be sure, the frequency of civil jury trials has steadily diminished over time. Still, understanding how jurors speculate might have parallels to other situations in which the law asks people to not consider certain information. I address several potential objections to the implementation of the provisional assumption and argue that implementation of psychological innovations helps to conform the underlying rationale of the law with legal actors’ expectations.

          [1].      Terry v. Plateau Elec. Coop., 825 S.W.2d 418, 420 (Tenn. Ct. App. 1991).

          [2].      Id.

          [3].      Id. at 419, 421.

          [4].      Id. at 421.

          [5].      Id.

          [6].      Id. at 422.

          [7].      Id. at 421–22.

          [8].      Id. at 423.

          [9].      Id.

        [10].      Id. Under Rule 606 of the Federal Rules of Evidence, juror testimony may not be used to impeach a verdict unless “extraneous prejudicial information was improperly brought to the jury’s attention” or “an outside influence was improperly brought to bear on any juror.” Fed. R. Evid. 606(b); see also Warger v. Shauers, 574 U.S. 40, 48 (2014).

        [11].      Terry, 825 S.W.2d at 423.

        [12].      Id.

        [13].      See, e.g., Valerie P. Hans & Nicole Vadino, Whipped by Whiplash? The Challenges of Jury Communication in Lawsuits Involving Connective Tissue Injury, 67 Tenn. L. Rev. 569, 581 (2000); Tim A. Baker, Sizing Up Settlement: How Much Do the Merits of a Dispute Really Matter?, 24 Harv. Negot. L. Rev. 253, 257–58 (2019).

        [14].      See Lauren Gailey, “I’m Sorry” as Evidence? Why the Federal Rules of Evidence Should Include a New Specialized Relevance Rule to Protect Physicians, 82 Def. Couns. J. 172, 181 (2015).

        [15].      See Baker, supra note 13, at 257.

        [16].      See Fed. R. Evid. 411.

        [17].      See, e.g., 6 Jack B. Weinstein & Margaret A. Berger, Weinstein’s Federal Evidence art. IV (Mark S. Brodin ed., 2d ed. 1997).

        [18].      See Banks McDowell, The Collateral Source Rule—The American Medical Association and Tort Reform, 24 Washburn L.J. 205, 205 (1985).

        [19].      See Justin Sevier, Evidence Law and Empirical Psychology, in Philosophical Foundations of Evidence Law 349, 356–57 (Christian Dahlman, Alex Stein & Giovanni Tuzet eds., 2021).

        [20].      See Shari Seidman Diamond & Neil Vidmar, Jury Room Ruminations on Forbidden Topics, 87 Va. L. Rev. 1857, 1864–66 (2001); Sevier, supra note 19, at 356–58.

        [21].      See Roselle L. Wissler & Michael J. Saks, On the Inefficacy of Limiting Instructions: When Jurors Use Prior Conviction Evidence to Decide on Guilt, 9 Law & Hum. Behav. 37, 41–43 (1985); David Crump, Does Impeachment by Conviction Create Undue Prejudice? An Experiment and an Analysis, 53 Akron L. Rev. 1, 16 (2019). The effect of prior convictions on liability extends to civil contexts. See Kathryn Stanchi & Deirdre Bowen, This Is Your Sword: How Damaging Are Prior Convictions to Plaintiffs in Civil Trials?, 89 Wash. L. Rev. 901, 927–29 (2014). Although information about prior convictions might be admitted to undermine a defendant’s credibility, it also appears to increase her liability in the jury’s eyes. See Sarah Tanford & Michele Cox, The Effects of Impeachment Evidence and Limiting Instructions on Individual and Group Decision Making, 12 Law & Hum. Behav. 477, 488 (1988).

        [22].      See, e.g., Stanley Sue, Ronald E. Smith & Renee Gilbert, Biasing Effects of Pretrial Publicity on Judicial Decisions, 2 J. Crim. Just. 163, 170 (1974); Geoffrey P. Kramer, Norbert L. Kerr & John S. Carroll, Pretrial Publicity, Judicial Remedies, and Jury Bias, 14 Law & Hum. Behav. 409, 431 (1990); Gary Moran & Brian L. Cutler, The Prejudicial Impact of Pretrial Publicity, 21 J. Applied Soc. Psych. 345, 360 (1991).

        [23].      See Nancy Mehrkens Steblay, Jasmina Besirevic, Solomon M. Fulero & Belia Jimenez-Lorente, The Effects of Pretrial Publicity on Juror Verdicts: A Meta-Analytic Review, 23 Law & Hum. Behav. 219, 229 (1999); Kramer et al., supra note 22, at 431; Moran & Cutler, supra note 22, at 360.

        [24].      See Moran & Cutler, supra note 22, at 362.

        [25].      See Diamond & Vidmar, supra note 20, at 1863–64.

        [26].      Terry v. Plateau Elec. Coop, 825 S.W.2d 418, 421–23 (Tenn. Ct. App. 1991); see, e.g., Shari Seidman Diamond & Jonathan D. Casper, Blindfolding the Jury to Verdict Consequences: Damages, Experts, and the Civil Jury, 26 Law & Soc’y Rev. 513, 516 (1992); Diamond & Vidmar, supra note 20, at 1861.

        [27].      See Diamond & Vidmar, supra note 20, at 1864–65.

* Sharswood Fellow, the University of Pennsylvania Carey Law School. J.D., Harvard Law School (2017); Ph.D., Harvard University (2020). Many thanks to David Abrams, Kim Ferzan, Jill Fisch, Jonah Gelbach, Chris Hampson, David Hoffman, Jon Klick, Sandy Mayson, Serena Mayeri, Gideon Parchomovsky, Tess Wilkinson-Ryan, and Maggie Wittlin, and workshop participants at Albany, Brooklyn, Columbia, Chapman, Chicago, Duke, Florida State, Fordham, George Washington, Georgia State, Minnesota, Texas A&M and Wyoming law schools, as well as conference participants at SEALS and the Inaugural Workshop for Asian American and Pacific Islander Women in the Legal Academy, for comments and conversations.


A Proposed Cure: More Expansive Conversion Therapy Legislation and the Limits of Parental Rights – Note by Nicole A. Meier

Article | Family Law
A Proposed Cure: More Expansive Conversion Therapy Legislation and the Limits of Parental Rights
by Nicole A. Meier*

From Vol. 93, No. 2 (January 2020)
93 S. Cal. L. Rev. 345 (2020)

Keywords: Sexual Orientation Change Efforts (“SOCE”), Conversion Therapy, Parental Rights

This Note will propose and examine the constitutional bounds of more expansive legislation that targets not just SOCE at the hands of state-licensed mental healthcare providers, but also at the hands of unlicensed providers—specifically religious leaders. Though more expansive legislation would likely trigger constitutional objections under the First Amendment, particularly with respect to free speech and free exercise rights, this Note will examine the constitutionality of this proposed legislation through the lens of parental rights under the Fourteenth Amendment.

This Note will proceed in the following order: Part I will examine the history and nature of SOCE, detail the current position of mainstream mental health professional associations regarding SOCE, and analyze current SOCE legislation and its deficiencies. Part II will propose more expansive SOCE legislation and establish that such legislation would not unconstitutionally infringe upon parental rights under the Fourteenth Amendment. Part III will analyze the limits that the Supreme Court has hitherto placed on parental rights, taking the defined limits of these rights in light of claims of religious freedom into special consideration. Parts IV and V will respond to anticipated critiques of the proposed legislation, focusing on the potential ease with which the legislation may be evaded and the ramifications that the legislation may have with respect to parental rights. Finally, Part VI will provide several policy justifications for the proposed legislation.

*. Senior Editor, Southern California Law Review, Volume 93; J.D. Candidate 2020, University of Southern California Gould School of Law; B.A. Philosophy 2016, Santa Clara University. Thank you to my parents, Josh and Barbara, for all of their encouragement and support. In addition, thank you to Professor Camille Gear Rich for encouraging me to pursue this topic and for her guidance during the drafting of this Note, and to Professor Scott Altman for his insight during the editing process. Finally, thank you to the talented Southern California Law Review editors for their excellent work.

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Is California Committed?: Why California Should Take Action to Address the Shortcomings of its Assisted Outpatient Commitment Statute – Note by Andrea Reynoso

From Volume 88, Number 4 (May 2015)

The history of the treatment of mental illness in the United States is anything but simple. While both social and scientific understanding of mental illness have developed tremendously in recent decades, there remain significant barriers to implementing effective treatment and rehabilitation programs for people with mental illness. Inherent in this intersection of law and mental health is the delicate balance between preserving liberty and autonomy interests on the one hand, and providing for individual and societal safety on the other. This balance is not easily achieved and remains the core debate surrounding much of today’s mental health legislation.



Beyond Facts and Norms: How Psychological Transparency Threatens and Restores Deliberation’s Legitimating Potential – Article by Arthur Lupia, Yanna Krupnikov & Adam Seth Levine

From Volume 86, Number 3 (March 2013)

In Between Facts and Norms: Contributions to a Discourse Theory of Law and Democracy, Jürgen Habermas describes a challenge to modern democracies and a procedure for adapting to this challenge. The challenge is that in the absence of natural law, or any other universally accepted moral or ethical code, no common framework informs people about what kinds of laws are, and are not, legitimate. Hence, if laws are to be accepted by, and hence binding on, the populations for whom they are intended to apply, an alternate legitimating mechanism is required.

Habermas describes communicative procedures that have the potential to provide legitimacy to collective decisions. In this ideal discourse (“ID”), as we describe it, all citizens have an equal right to speak and an obligation to listen. If deliberations culminate in agreement on the validity of socially relevant moral, ethical, or technical propositions, then the propositions serve as substantive foundations for subsequent legislative decisions and bureaucratic actions.



The Neurobiology of Opinions: Can Judges and Juries Be Impartial? – Article by Isabelle Brocas & Juan D. Carrillo

From Volume 86, Number 3 (March 2013)

In this Article we build on neuroscience evidence to model belief formation and study decisionmaking by judges and juries. We show that physiological constraints generate posterior beliefs with properties that are qualitatively different from traditional Bayesian theory. In particular, decisionmakers will tend to reinforce their prior beliefs and to hold posteriors influenced by their preferences. We study the implications of the theory for decisions rendered by judges and juries. We show that early cases in judges’ careers may affect their decisions later on, and that early evidence produced in a trial may matter more than late evidence. In the case of juries, we show that the well-known polarization effect is a direct consequence of physiological constraints. It is more likely to be observed when information is mixed, as behavioral evidence suggests, and when prior beliefs and preferences are initially more divergent across jurors.



Examining Empathy: Discrimination, Experience, and Judicial Decisionmaking – Article by Jill Weinberg & Laura Beth Nielsen

From Volume 85, Number 2 (January 2012)

There are moments when the law is not enough.

In Virginia v. Black, a normally silent Justice Clarence Thomas interjected with what one commentator called a “Luke-I-am-you-father” voice. The case involved a First Amendment challenge to a Virginia law that prohibited cross burning. During a deputy U.S. solicitor general’s oral argument in favor of the law, Justice Thomas condemned him for not going far enough. Justice Thomas, who grew up in the segregated South and was the only black Justice on the bench, posed a very potent question: “Aren’t you understating the . . . effects of . . . the burning cross” given that crosses were “symbol[s] of [a] reign of terror” during the “100 years of lynching . . . in the South?” He continued, “I think that what you’re attempting to do is to fit this into our jurisprudence rather than stating more clearly what the cross was intended to accomplish.”

Similarly, during the Senate Judiciary Committee hearing on the nomination of then-nominee, now-Justice Sonia Sotomayor, Senator Jeff Sessions challenged her prior representations that she could be an impartial judge by quoting remarks she made the day before: “You have repeatedly made this statement: ‘I accept the proposition that a difference there will be by the presence of women and people of color on the bench, and that my experiences affect the facts I choose to see as a judge.’” Without hesitation, Sotomayor responded, “the point that I was making was that our life experiences do permit us to see some facts and understand them more easily than others.” Ultimately, Senator Sessions made his stance clear that empathy and judicial decisionmaking can and should be mutually exclusive, saying, “Call it empathy, call it prejudice, or call it sympathy, but whatever it is, it is not law. In truth, it is more akin to politics, and politics has no place in the courtroom.”



Beyond No-Man’s Land: Psychiatry’s Imprecision Revealed by Its Critique of SVP Statutes as Applied to Pedophilia – Note by Jennifer Jason

From Volume 83, Number 6 (September 2010)

The field of psychiatry has identified a problem with the law, its source, and suggested a solution. The problem is “legislators . . . us[ing] psychiatric commitment [of sex offenders] to effect nonmedical societal ends.” The source is U.S. Supreme Court decisions allowing legislatures to use definitions of mental illness that have no basis in psychiatry: “As a consequence of U.S. Supreme Court decisions that are written ambiguously and tentatively, the bright line separating . . . [the legal conception of] mental disorder [(for the purposes of civilly committing sex offenders under sexually violent predator statutes)] from ordinary criminal behavior is difficult to draw and tests a no-man’s land between psychiatry and the law.” 

The solution is “[g]reater clarity and standardization . . . com[ing] from both sides: the legalists who interpret the law and the clinicians who apply and work under it.” A close analysis of the psychiatric critique of these statutes that allow for the civil commitment of sex offenders reveals psychiatry’s own imprecision within the bounds of psychiatry and in the domain of the overlap between psychiatry and the law.



Thwarting California’s Presumptive LWOP Penalty for Adolescents: Psychology’s and Neuroscience’s Message for the California Justice System – Note by Ashley N. Johndro

From Volume 83, Number 2 (January 2010)

In California, adolescents convicted of special circumstance first-degree murder are presumptively sentenced to life without the possibility of parole (“LWOP”) pursuant to section 190.5 of the California Penal Code. To date, California has sentenced more than 250 adolescents to die behind bars. Recent studies in psychology and neuroscience challenge this status quo. These disciplines suggest that adolescents are biophysically determined to suffer from poor decisionmaking capacities and behavior control. This Note argues that adolescent culpability is mitigated by currently valued standards, informed by science’s conception of the adolescent, and that adolescent crimes consequently warrant the lesser punishment of twenty-five years to life.