In our previous article, “Confirmation Bias: The Science Behind its Impact on Jury Selection and Litigation”, we explored the concept of confirmation bias and its profound effects on jury selection and decision-making processes. We emphasized the need to recognize and address this cognitive bias in the legal system. Building upon that foundation, this article delves deeper into the circumstances and individuals affected most significantly by confirmation.

Confirmation bias permeates the litigation process, affecting various stages from trial preparation to jury deliberation. Therefore, it is crucial to be mindful of its influence on all individuals involved in a trial, including legal professionals, trial consultants, and the jury themselves. By understanding how confirmation bias impacts each step of the litigation process, it is possible to take proactive steps to mitigate its effects on trial outcomes. 

Relying on Pseudoscience During Jury Selection

During jury selection, trial consultants can play a vital role in identifying and evaluating potential jurors who may be favorable or unfavorable to a client’s case. However, that role is entirely contingent on the validity of their approach. Scientific prediction of juror behavior based on various individual characteristics is possible, but only if premised on a valid scientific framework. Trial consultants who circumvent the safeguards of the scientific method undermine their effectiveness by relying on pseudoscience or purporting to act as “intuitive psychologists”. 

Numerous “how-to” books on trial practice have touted pseudoscientific advice, masquerading as psychological research. Some of the resulting “psychological” claims include:

  • Cabinetmakers are meticulous and so will never be satisfied with the evidence.
  • Athletes won’t feel sympathy for anyone they perceive as fragile.
  • People from Scandinavia will favor the prosecution.
  • You can determine a good juror by how much you like their face.

Pseudoscientific ideas are often perpetuated by confirmation bias. Pseudoscience is based on subjectivity and intuition, rather than objectivity and empiricism. This means that the ideas it promotes are easily adopted by others because of their simplicity, subjectivity, and intuitive appeal and given the human propensity for belief perseverance, ideas are resilient once they take hold. 

To address this issue, it is important to distinguish between psychological science and psychological pseudoscience. While both make claims about human behavior and cognition, they are distinguished by a very critical factor: psychological science adheres to safeguards that protect against confirmation bias, whereas psychological pseudoscience does not. Human intuition is useful, and in fact is often crucial for generating hypotheses. Science is only meant to objectively test whether or not those intuitions hold up when put to the test.  

Impact on Attorneys During Trial Preparation

Attorneys are also not immune to the effects of confirmation bias, which can affect their own approach to trial preparation, jury selection, and evidence evaluation. 

  1. Selective Case Evaluation: Confirmation bias can lead attorneys to favor information that confirms their initial assessment of a case, potentially leading them to downplay or disregard contradictory evidence. This bias can distort their perception of the strengths and weaknesses of their own case and hinder their ability to make objective judgments regarding case strategy and potential outcomes.
  1. Oral Voir Dire & Jury Selection: Confirmation bias can extend to oral voir dire and the process of jury selection. Attorneys may have preconceived notions about what makes a good juror generally and speaking and based on their own intuitive case theories. These predetermined expectations about what makes a good juror can skew how jurors are evaluated during jury selection, regardless of what the evidence collected during voir dire suggests.  In one study [1], attorneys were given juror profiles and asked to create an oral voir dire strategy based on those profiles. The results indicated that they used their expectations to formulate intuitive theories about those jurors. Their voir dire strategies involved asking questions geared towards confirming their theories, which ultimately led to the formation of conclusions that were biased by the questions they asked. They heard what they expected to hear because they asked questions designed to prove they were right. Given what we know about confirmation bias, it is probably not surprising that research suggests that an intuitive approach to jury selection is ineffective. In fact, studies find that lawyers cannot effectively predict how jurors will vote, either based on their intuitive rules of thumb [2] or by how they interpret prospective jurors’ responses during oral voir dire [3, 4]. Accepting that relying on intuition alone has not only limited utility would not only be advantageous for individual attorneys but would contribute to a fairer trial process. 
  1. Document and Evidence Evaluation: During the discovery phase, confirmation bias can impact the evaluation of documents and evidence. Attorneys may be more inclined to assign greater significance to evidence that supports their case while discounting or minimizing the relevance of contradictory evidence. This biased evaluation can distort the presentation of evidence and weaken the overall integrity of the legal arguments. 

Jurors’ Biased Processing of Evidence and Information During Trial:

Distorting new information so that it conforms with your pre-existing beliefs is a central hallmark of confirmation bias. Confirmation bias leads jurors to selectively focus on the evidence that supports their initial beliefs, disregard or explain away evidence that does not align with those beliefs, and distort evidence that is ambiguous.

  1. Interpretation of evidence: In a demonstration of how confirmation bias can distort the evaluation of new evidence, one study had participants read a mock police file containing only weak circumstantial evidence that pointed toward one potential suspect [5]. After reading this, some participants were asked to predict who they thought was guilty. Once they had established their belief regarding the suspects’ guilt, they began looking only for evidence that would confirm this initial prediction and interpreted ambiguous evidence as confirming their prediction that the suspect was guilty. 

Consider how this can be affected by pre-trial publicity or holding stereotypical beliefs about the suspect based on their group membership. If a juror comes into the trial with a prediction about the outcome, all evidence will be processed in a manner that bolsters their initial assumptions. 

  1. Influence on witness credibility assessment: Jurors may disproportionately believe, or discredit, witnesses based on whether their testimony aligns with their preconceived notions. This can compromise the fairness of the trial, as witness credibility is a critical factor in the determination of guilt or innocence. 
  1. The role of confirmation bias in juror deliberations and decision-making: By the time of deliberation, confirmation bias may have already affected their evaluation of the evidence and witness testimonies that were presented to a jury. It is, therefore, likely that if a juror held a case-relevant belief, those initial beliefs have been strengthened by the time deliberation begins. During the deliberation, jurors would then be even more likely to cling to those beliefs and resist changing positions. If other jurors share those opinions, then group discussions will reinforce existing biases to further entrench those biases and hinder objective decision-making. 

The Importance of Mitigating Confirmation Bias

By the time jurors enter the deliberation phase, confirmation bias may have already shaped the composition of the jury and the jurors’ evaluation of evidence and witness testimony. These initial biases tend to be reinforced during group discussions, making it challenging for jurors to change their positions and hindering objective decision-making. To counteract confirmation bias, 

it is essential to implement strategies that promote fairness and impartiality in jury deliberations.

In our next and final article in this series, “Mitigating Confirmation Bias for Fair Trials,” we will explore a range of strategies and techniques to mitigate the influence of confirmation bias within the legal system. We will discuss the importance of diversity in jury panels and its impact on reducing bias. Additionally, we will advocate for enhanced education and awareness of bias among jurors and legal professionals, emphasizing the need for continued learning and self-reflection. By implementing best practices to minimize the influence of confirmation bias, we can strive for more just and impartial trial outcomes.

Join us in the concluding part of this series as we explore practical approaches to mitigate confirmation bias and foster a more equitable legal system. 


  1. Otis, C. C., Greathouse, S. M., Kennard, J. B., & Kovera, M. B. (2014). Hypothesis testing in attorney-conducted voir dire. Law and Human Behavior38(4), 392. 
  2. Olczak, P. V., Kaplan, M. F., & Penrod, S. (1991). Attorneys’ lay psychology and its effectiveness in selecting jurors: Three empirical studies. Journal of Social Behavior and Personality, 6(3), 431.
  3. Kerr N. L., Kramer, G. P., Carroll, J. S., & Alfini, J.J. (1991). On the effectiveness of voir dire in criminal cases with prejudicial pretrial publicity: An empirical study. American University Law Review, 40, 665-701.
  4. Zeisel, H., & Diamond, S. S. (1978). The effect of peremptory challenges on jury and verdict: An experiment in a federal district court. Stanford Law Review, 491-531.
  5. O’Brien, B. (2009). Prime suspect: An examination of factors that aggravate and counteract confirmation bias in criminal investigations. Psychology, Public Policy, and Law15(4), 315-334.