Manipulating Jury Biases

The top google link for the phrase "Overcoming Bias", other than links associated with this forum, is to a book length pdf called "Overcoming Jury Bias."  This is a well written guide to lawyers on how to get a jury to agree with them.   It does show how to overcome jury bias when that would help you, but it also shows how to enhance jury bias when that would help you:

A woman who claims to be the victim of a sexual assault must appear in court as a "victim". If the woman appears before the jury wearing tight clothing, ostentatious jewelry, overdone cosmetics and a wild hair style, this will create an incongruence in the minds of the juror of this woman as a "victim". …

Your first witness should be very carefully selected with the goal of helping the jurors to perceive, understand and adopt your model of the case as their own. … a trustworthy, unimpeachable storyteller …

The attorney needs to get the jurors to set aside their belief that "doctors don’t make mistakes" solely for the course of this trial, solely for this doctor and solely for this patient in this surgery. … As soon as this medical negligence trial is over, it is fine for the jurors to revert to their previously held view that "doctors don’t make mistakes."  … You have told them it is all right to believe that doctors do not make mistakes….

There can be no doubt about it, we like people like ourselves. We want to be with others who are similar to us. … if a lawyer tries a case in Florida where other lawyers dress more casual, then he too should dress more casual.  During voir dire ask jurors about their hobbies. If a juror has a hobby and you know something about the subject matter, let the juror know that you have the same hobby. It is all efforts to raise feelings of similarity on the conscious level.  Feelings of similarity help create "liking" on a conscious and unconscious level. … if a juror enjoys bowling, we may at some point in addressing the jury utilize the metaphor about "rolling a strike" …

Unfortunately, people probably suspect we have the same motives here, to twist other people’s biases to our advantage.   Let us try hard to avoid the fact or impression of such motives, but honestly, a good way to overcome our own biases is to read about the ways professionals manipulate our biases to their advantage. 

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  • JMG3Y

    I expect that this has to be applied in a very subtle fashion as jurors likely react negatively when they perceive they are being overtly manipulated. It seems that we maintain the fiction that we individually aren’t particularly susceptible to bias, that we remain somewhat suspect of most others but that we generally ignore the evidence on most all counts.

    For example,in the political arena, most politicians successfully make perpetual claims that they are not biased by lobbyists and campaign contributions in their attempt to maintain the perception that they are impervious to such manipulation and cannot be bought. And many voters apparently believe these statements from most politicians (or else believe that their returns from their own lobbying portals are greater than their taxes). But empirical evidence to the contrary abounds. If this were truly the case, lobbyists would likely not be nearly so well paid. Showing that businesses are not investing in lobbyists or making campaign donations for altruistic reasons but rather to increase shareholder value would likely be a fairly trivial exercise if it hasn’t been done. Politicians wouldn’t be nearly so resistant to lobbying and campaign reform. Rather than maintaining the position that reform isn’t needed because bias isn’t a problem, they would more likely implement change to remove the negative image.

    How much can we overcome our biases by improving our understanding of their presence? Sometimes, we really want the opportunity for bias because it pays off and we aren’t nearly as rational or logical as we perceive ourselves to be. Of what benefit is evidence? In the end, just like everyone else the juror wants to go home feeling good about what they have done, whatever twisting occurs to accomplish that.

  • Robin Hanson

    JMG3Y, you are right that it is not clear how far understanding goes to overcome biases. Improving our incentives to reduce bias may often be more effective.

  • Curt Adams

    I suspect it would help jurors be less biased, and less manipulable, if *they* read the book.

  • Carl Shulman

    Manipulation of others is often constrained by social norms and interactions, in a way that private application need not be. For instance, since authors for economics papers are listed in alphabetical order, those with early surnames get an unjustified advantage:

    The manipulative application of this is to change one’s last name to Aachen or Aaronson, but if this is done too obviously (as opposed to choosing to take a spouse’s name or not) it risks making one a laughingstock, negating the hoped-for benefits. This risk of social backlash is absent when information is used in secret, or at least private deliberations, e.g. an investor attempting to perform a meta-analysis of financial economics literature can discount early-surname authors in the aggregation.

  • Anders

    [ I happened to stumble upon this yummy source of biases: M.B. Kovera, J.J. Dickinson & B.L. Cutler, Chapter 10: Voir Dire and Jury Selection in Handbook of Psychology vol 11 (Forensic Psychology) eds. Goldstein & Weiner, Wiley 2003 ]

    Jury selection is another clear source of bias. There is a lot of “jury selection folklore” according to Fulero & Penrod, such as the use of poor jurors to bias towards lower damages (since they might not understand large sums of money) – but others claim there is a Robin Hood effect making them somewhat vindictive – that having similar jurors to the client may cause both an empathy effect but also a black sheep effect where they punish clients who reflect poorly on their group, and so on. Given the contradictions and anecdotal nature of this, we should expect that a lot of this is just plain wrong but that people try to select juries based on heuristics from this kind of folklore.

    There have been studies demonstrating that jury selection do affect the outcome. Zeisel and Diamond (1978) took 12 jurors who were removed through peremptory challenges to remain as observers and give their own verdict. Comparing with the remaining and replacement jurors, it turned out that the selection did affet the outcome but that attorneys were bad at predicting how the jurors would vote. Johnson and Haney (1994) found that defense and prosecution were reasonably good at excusing biased jurors, but that this did not affect the overall bias of the entire jury.

    There appears to be research trying to reduce or control for juror bias, so called “scientific jury selection”. People are selected based on their demographics rather than as individuals, based on found correlations between demographics and opinions in a community survey. The big problem is that it is impossible to determine the contribution of scientific jury selection to a trial’s outcome in any particular case. It seems hard to really call it scientific. There has been a few attempts to compare the method with normal decisions such as (Horowitz, 1980), but that was rather inconclusive.

    Some studies have not found any link between juror age, gender, marital status, and occupation were unrelated to damage awards (Goodman, Loftus, & Greene, 1990). Other studies suggest that jurors who have higher incomes, more prestigious
    occupations, or higher educational levels are more likely to convict than are jurors with a lower socioeconomic status (Adler, 1973; Simon, 1967). Early research suggested that Black mock jurors were more likely to acquit defendants using an insanity defense than were White mock jurors (Simon, 1967), but there may also be a black-sheep effect (Nietzel & Dillehay, 1986). Gender appears to predict verdicts in cases that involve issues such as rape, domestic violence, and sexual harassment, issues on which men’s and women’s attitudes often differ. There is little evidence to suggest that gender is a reliable predictor of
    verdict in other types of cases.

    Overall, there doesn’t seem to be any evidence showing that the decisions of a voir dire jury is any better than a randomly selected jury.

  • Robin Hanson

    Anders, interesting; that would have made a fine post on its own.

  • TGGP

    I think I remember Alex Tabbarok giving a presentation at AEI on the Bronx jury redistributing the wealth.
    Here it is:,eventID.1329/summary.asp