Top Psychological Biases That Influence Jurors in Trial

By: Michelle M. Pena

Ever wonder why jurors see the same evidence but reach wildly different conclusions? The courtroom is not just a battle of facts; it’s a battle against hidden psychological biases shaping each juror’s interpretation of the evidence. Although jurors are asked to make decisions solely based on evidence and instructions, the reality is there are psychological biases at work (unconsciously and thus unintentionally) that ultimately shape how jurors process evidence, evaluate witnesses, and reach verdicts. Recognizing and understanding these biases is critical for attorneys seeking to communicate effectively with jurors to successfully present their case

Biases That Impact Jurors

1. Confirmation Bias: Seeing What You Want to See

Jurors are not blank slates. Each juror who walks into the courtroom carries their own life experiences, opinions, and attitudes, all of which shape how that juror interprets the evidence, and perceives the litigants and the attorneys. Confirmation bias is the tendency to seek out, attend to, and better recall information (e.g., evidence, arguments) that confirms one’s preexisting beliefs or initial impressions formed early in trial while often ignoring or explaining away contradictory information or evidence (Nickerson, 1998).

It is important to highlight that confirmation bias, as with most cognitive biases, occurs automatically without an individual’s awareness (Kunda, 1990). Jurors are neither purposefully seeking out information that confirms their pre-existing beliefs nor deliberately choosing to ignore information or evidence that does not fit with their hypothesis. As such, confirmation bias can have a powerful influence on how jurors process a case, regardless of the facts or instructions presented in court.

2. Defensive Attribution: Protecting Themselves from Blame

Defensive attribution is a cognitive bias we use to protect ourselves from the fear that something negative that happened to someone else could happen to us (Shaver, 1970). Jurors will try to distance themselves from an individual that something negative happened to and will tend to assign more blame to a party if that juror perceives the harm as preventable and wants to believe s/he would have acted differently in the same situation.

In personal injury, negligence, or even financial fraud cases, jurors may increase blame if they feel vulnerable to similar harm, using blame as a psychological defense to reassure themselves it would not happen to them. For example, if a plaintiff suffers an injury from a car accident, jurors may focus on what the plaintiff “should have done” to avoid the accident to reduce that juror’s own feelings of vulnerability. In a securities case, jurors may shift blame onto the investor-victims by focusing on what the juror believes s/he would have done differently to avoid being defrauded, such as conducting more due diligence before investing.

To reduce defensive attribution, attorneys should consider jurors’ sense of personal risk and address how an injury or incident was outside the plaintiff’s control.

3. Anchoring Bias: What They See/Hear First Matters

The first piece of evidence or numerical value presented can serve as a psychological anchor, influencing how jurors evaluate subsequent evidence or damages. For example, an attorney’s suggested damages number can anchor jurors’ perceptions of what a reasonable award should be, even if they intend to remain objective (Robbennolt & Studebaker, 1999). Anchors proposed by plaintiff attorneys create a psychologically powerful baseline for jurors who often struggle with assigning a monetary value to difficult-to-define damages. That is why anchoring typically has the greatest impact on noneconomic damages – because of their subjectivity. Also, the first explanation of “what happened” may anchor jurors’ understanding of the facts, influencing how they interpret subsequent testimony and evidence.

Attorneys can strategically use anchors during opening statements or damages discussions, while also preparing to counter unfavorable anchors set by the opposing side.

4. Hindsight Bias: Monday Morning Quarterbacking

After learning how events turn out, jurors may believe the outcome was more predictable than it actually was, affecting cases involving negligence and/or foreseeability. Hindsight bias is the tendency, after all the information about an event is known, to perceive an event or occurrence as having been preventable regardless of the circumstances (Fischoff & Beyth, 1975). For example, in a product liability case, if a product causes an injury, jurors may believe the danger was obvious and that the manufacturer should have predicted and prevented the harm, even if the risk was low or not widely recognized at the time. This bias can disadvantage defendants who are judged by what jurors know now, rather than what was knowable at the time of the alleged wrongdoing.

Attorneys can reduce the impact of hindsight bias by using counterfactuals. Counterfactuals cause jurors to think about alternative outcomes based on what was known at the time the choice was made. Using “if only” statements is often effective in countering hindsight bias (e.g., “If only we knew then what we know now about how this injury happened, we would see the risk clearly. But at the time, without the benefit of hindsight, this risk was not obvious”). Hindsight bias can also be reduced by taking jurors back to the time and place immediately before the decision or choice was made – reminding jurors of what was known at that specific time and place (i.e., a lot less than what is known now).

Concluding Remarks

The courtroom is not just a forum for facts and law. It is a human environment shaped by perception and bias. By recognizing and understanding confirmation bias, defensive attribution, anchoring bias, and hindsight bias, attorneys can tailor their strategies to align with jurors’ decision-making processes, leading to more effective advocacy and better outcomes at trial.

Citations

• Fischhoff, B., & Beyth, R. (1975). “I knew it would happen”—Remembered probabilities of once-future things. Organizational Behavior and Human Performance, 13(1), 1–16.
• Kunda, Z. (1990). The case for motivated reasoning. Psychological Bulletin, 108, 480-498.
• Nickerson, R.S. (1998). Confirmation bias: A ubiquitous phenomenon in many guises. Review of General Psychology, 2, 175-220.
• Robbennolt, J.K., & Studebaker, C.A. (1999). Anchoring in the Courtroom: The Effects of Caps on Punitive Damages. Law and Human Behavior, 23, 353–373.
• Shaver, K. (1970). Defensive Attribution: Effects of Severity and Relevance on the Responsibility Assigned for an Accident. Journal of Personality and Social Psychology, 14(2), 101–113.