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Commitment Effects: Does Asking Verdict Questions Early Commit Mock Jurors to a Position?

When we design a mock trial – where jurors are read instructions and deliberate to a verdict form – we concentrate on presenting the case facts, witnesses, and evidence in a way that will impact jurors’ story of the case similarly to a “real life” trial.  As such, we typically wait until after jurors hear the plaintiff’s rebuttal to read jury instructions and have them deliberate to a verdict form.  Deliberations are thereby the first time jurors are processing their initial decision-making about the specific verdict questions.

But should researchers wait until deliberations to have jurors answer verdict questions?  What about asking some of those verdict questions earlier in the test, such as after the plaintiff’s and defendant’s cases-in-chief?  Some researchers prefer the latter, and some clients request it.  So which is the better research methodology?


Persuasion Psychology and the Possible Effect on Juror Verdicts

The answer to those questions may lie in long-standing findings on the psychology of persuasion, which taught us that early commitment to an idea leads to a greater likelihood of persuasion to that idea later[1] – this is more commonly known as a “commitment effect.”  This effect combines with the “consistency principle,” whereby people form an initial impression of themselves (e.g., as a pro-plaintiff voice) and like to view themselves as behaving consistently with their past opinions or behaviors.

Therefore, to maintain the most valid results from our jury research, we have traditionally avoided asking jurors specific verdict-related questions before deliberations because of the possibility of a commitment effect, which would increase the likelihood that jurors’ case leanings show less variance throughout the day.  In other words, we don’t want jurors to lock into a position before hearing and considering the full case.

Testing the Commitment Effect Theory

Recently, some of our clients have asked us to incorporate verdict-related questions throughout the research, rather than waiting until deliberations.  We saw this as a real-world opportunity to test the commitment effect theory.  Our hypothesis was that asking verdict-related questions earlier in the jury research process would indeed create a commitment effect for jurors going into deliberations, signified by a reduced variability in jurors’ case leanings across the day.

To test this hypothesis, we created a dataset from six mock trials (190 total jurors).  For three of these mock trials, we asked verdict questions throughout the day, beginning after the plaintiff’s case in chief; for the other three we used our traditional methodology, whereby jurors do not answer any verdict questions until they begin deliberations.

In all six tests, jurors were asked to document their case leaning on a seven-point scale where 1 = “Strongly Favor the Defendant” and 7 = “Strongly Favor the Plaintiff.”  We gathered these leanings at several points: after openings, after each case-in-chief, after closings and rebuttal, and after juror deliberations.

Results: Asking Verdict Questions Before Deliberations Creates Commitment Effects

For each juror, any shift in leaning from one juncture to the next was calculated, converted to an absolute value, and summed – providing a measure of “total case leaning change” by juror over the course of the day.  Next, jurors were categorized into two groups, based on whether they had been part of a mock trial with “early verdict questions” or with “deliberations-only verdict questions.”  The jurors’ “total case leaning change” data was then submitted to a statistical analysis[2] to assess the differences, if any, between the two test groups.

Ultimately, the statistical analysis was clear – there was significantly less variability in jurors’ case leanings over the course of mock trials when they responded to verdict questions during the day and before deliberations.[3]  The results supported the hypothesis that jurors would experience a commitment effect in their case leanings when asked verdict questions before deliberations. 

Priming Case Issues Before Deliberations May Affect the Course of Deliberations

Now, did answering those verdict questions earlier in the research process dramatically change the direction of deliberations or the strength of the discussion?  Unfortunately, that is an open question that is impossible to answer in a real-world setting without compromising our mock trial tests.

That said, one can exacerbate the commitment effect or influence deliberations by priming jurors with issue-based questions from both sides’ perspectives before deliberations (but after the plaintiff’s rebuttal).  At Litigation Insights, we administer a final issue-based questionnaire (the “Exit questionnaire”) after deliberations and verdict forms are completed, to avoid influencing jurors’ deliberation discussions.  Avoiding influencing factors is particularly important because deliberations offer an opportunity to better understand what evidence and themes resonated for jurors, which facts they best recalled, and which arguments fell flat when they received little attention in the group discussion.

Opportunely, we recently had the chance to watch mock jurors deliberate after they had already completed a final issue-based questionnaire.  Although the findings are qualitative, when compared with our experience of over 20 years watching thousands of mock jurors deliberate, the deliberation content in this case certainly appeared to be influenced by having completed an Exit questionnaire before discussing the issues and rendering a verdict.  Of particular note were the points made by several jurors in deliberations that closely echoed some of the more minor, nuanced issues covered in the questionnaire, all of which were unusual details for jurors to bring up in discussions.  Without a comparison group or statistical measures, it is impossible to say with certainty that deliberations were affected by the issue-based questionnaire before deliberations, but from a veteran consultant’s view, the questionnaire appeared to affect some jurors’ arguments in deliberations.


In any research design, it’s important to consider the validity of the outcome and weigh the effects of potential influencers.  Given the results of our recent analyses, it is likely important that jury researchers inform clients about the potential for commitment effects in jurors’ case leanings, so they can weigh the pros and cons if they wish to introduce verdict questions early on.

Furthermore, these results beg additional troubling questions: How might actual trial jurors’ leanings and verdicts be affected in venues that allow jurors to discuss the case and their views as the trial progresses, rather than ordering jurors to wait until deliberations?  Could this potentially benefit plaintiffs, since jurors are allowed to discuss the evidence before the defendant puts on its case?



Jill-LieboldBy: Jill Leibold, Ph.D. – Director – Jury Research




[1]  Freedman, J. L., & Fraser, S. C., Compliance Without Pressure: The Foot-in-the-Door Technique, JPSP, 1966, 4, 196-202; Cialdini, R.B. (2007). Influence: The Psychology of Persuasion.
[2]  The data was submitted to an independent samples t-test, t = -2.78 (2,188), p < .01, which revealed significant differences in the overall variation of jurors’ case leanings between the two groups.
[3]  Specifically, there was an average difference in leanings change of 1.61 points.  The “early verdict questions” group averaged 6.02 points in leanings change (standard deviation 3.35 points) over the day, compared to an average of 7.63 points in change (standard deviation 4.53) in the “deliberations-only verdict questions” group.  Note that the standard deviation – the measure of variance in scores for a group – is also smaller for the “early verdict questions” group, another indicator that jurors’ changes to their leanings were smaller in that group.

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