Juries are the backbone of the judicial trial system in the United States. They make the ultimate decision regarding the charges of a defendant. Ultimately, the entire trial is based on convincing the jury that your point is the truth. They are required to weigh the evidence and stories both sides present and then deliberate together to reach a decision that decides the outcome of the case. Jurors, however, are human and are subject to several biases and methods of persuasion. The primary biases that juries are subject to are pre-trial bias, cognitive bias, and bias from external legal actors.[1]
Juror Bias
Pre-Trial Bias
In a landmark experiment within the jury psychology field, it was found that “jurors’ biased interpretation of new evidence to support whichever verdict is tentatively favored as a trial progresses.” [2] This is called pre-decisional distortion. This revealed that jurors tend to favor a verdict before all the evidence is presented, and view the evidence they are presented with in favor of the verdict they have already decided on. This can result in biased outcomes. A potential way around this is to include in jury instructions not to avoid making pre-judgments in the trial until all evidence is considered.
Additionally, in the age of technology, pre-trial biases such as pre-trial publicity can influence the jury’s bias through the internet and social media, which can affect their opinion in the case. Many jury questionnaires include questions about this and confirm whether or not they have heard about the case prior to becoming a juror as a way to combat this. If it is not included, it should be asked during voir dire.
Cognitive Bias
Cognitive bias occurs when there are subjective perceptions of individuals that may influence the decisions they make and how they interact with the world.”[3] This is often due to the way individuals view the world and certain scenarios and actions in their own way, and subsequently, the heuristics that humans often use. Heuristics are a prominent part of cognitive bias. “A heuristic is a mental shortcut that allows an individual to make a decision, pass judgment, or solve a problem quickly and with minimal mental effort.”[4] Heuristics are like cognitive shortcuts, and if the language you use is too complicated or the information too much, this can lead the jury to rely on heuristics that may not result in an outcome in your favor.
Bias from External Legal Actors
Expert testimony is an important part of a trial and can help break down complicated pieces of evidence, and depending on how effective the presentation of the expert witness is, it can have a major impact on the outcome of a case. However, expert testimony can be impacted by numerous factors such as “the type and complexity of evidence they are giving testimony on (e.g. eyewitness, footwear, DNA) the type of expertise they are communicating (e.g. clinical or actuarial; ) the characteristics of the expert (e.g. gender, appearance, attractiveness; ) the conditions of their testimony (e.g. pay rate, frequency of testimony) their manner of presenting (e.g. categorical like high/low, or likelihood ratios and numerical expressions) and their willingness/ability to testify about their own doubts and biases.“ [5] These factors can have a positive or negative impact on an expert’s testimony. For example, DNA evidence is marked as having either a correct result or not. This makes jurors think that DNA evidence is concrete and can influence how strongly they weigh DNA evidence. [6]
To eliminate some of these biases, Jury selection should be performed to create heterogeneous juries that challenge each other’s individual biases, increasing the quality of expert and lay witness training through practice, and educating lawyers and jurors about biases that we all inherently carry.[7]
Language and Emotion
There are several ways to help persuade the jury to your side of the matter, as well as several things to keep in mind when preparing for a jury trial. It is important to remember that jurors are normal, everyday people who are not legal experts. As a result, jurors can be “overwhelmed by the legal terminology being directed at them and confused due to the adversarial system of the courtroom. This cognitively taxing environment may cause jurors to have a low elaboration likelihood and thus utilize bias when reaching their verdict.”[8] Therefore, it is important to keep much of your courtroom vocabulary simple and avoid using legal vocabulary otherwise known as “legalese” that makes it too hard for jurors to understand and, as a result, have them disregard that information. “Both laypeople and legally trained individuals tend to respond more positively to attorneys who use clear, jargon-free language, perceiving them as more credible and relatable.”[9] The better the jury is able to understand and comprehend what you are saying, the more relatable you seem to the jury, as well as more reliable.
“Cognitive load is the concept that the brain has only a finite ability to process new information and that learning and recall are impaired by overloaded short-term memory. Studies have shown that the less effort it takes to process a factual claim, the more accurate it seems.”[10] It is important to convey information as simply as possible and even group large topics into sections to make it easier for jurors to digest and understand. “Human experience has demonstrated that people can understand and remember things that are grouped into three sections.” The rule of three has been used as a persuasive and informational technique for centuries, and it has been proven that when information is grouped into sections of three, people are more likely to listen and comprehend the information.
How an attorney communicates impacts how the jury receives that information. Research suggests that overly professional, neutral, and objective tones and use of and uses emotionally neutral communication can undermine the attorney’s trustworthiness.[11] Jurors can view this objective tone as detached or unfeeling and diminish the level of persuasiveness it can have on the jury. The emotional weight of an attorney’s words impacts the jurors’ perception and interpretation of information. It is important to make sure your story and the tone in which you convey your words as the attorney carries an emotional weight to it that will connect with the jury and have them siding with you. “Attorneys who use emotionally resonant language are often perceived as more credible than those who default to abstract, emotionally flat styles of communication. Furthermore, attorneys’ use of assertive, concrete language is associated with jurors viewing them as more persuasive.”[12] For example, saying the father died as a result of him being shot in the abdomen by his wife is more concrete than saying the victim died from a gunshot wound. This specificity of language resonates with the jury more than being vague. Being concrete and emotional with your language is more likely to influence the jurors in your favor.
Additionally, the use of positive, negative, or neutral language can impact the jury as well. Studies found that “attorneys using abstract, negative, and dispositional language (e.g., “He is aggressive”) increased juror guilt attributions and likelihood to increase the sentence of damages; using concrete, neutral, or situational language (e.g., “He shouted”) led to jurors reducing blame and punishment.”[13] Depending on who your client is, it is important to know when to speak positively, when to remain neutral, and when to speak negatively on matters relating to your client and the case. Depending on the type of language used, it can sway the jury to your side or to the other side if the wrong form of language is used.
Body Language and Witness Preparation
Body language is an important factor during a trial. The jury is observing both your movements as well as the movements of the witnesses you put on trial. Certain behavior, such as repetitive behavior or signs of agitation, can reflect poorly on the jury. Juries may see these movements as signs of deception. These body movements that can make the witness seem deceptive to the jury are known as adaptors. Signs of agitation or repetitive movements for the witness may make the witness seem deceptive to the jury. “Adaptors are generally defined as repetitive, unnecessary peripheral body movements, such as fidgeting. These movements usually occur as a means for a person to release excess levels of internal stress, allowing them to ‘adapt’ to the present situation. Witnesses may exemplify this behavior by bouncing a leg up and down, adjusting their glasses, swiveling their chair, taking too many drinks of water, or playing with a pencil.” [14] These restless movements can make you and your witness seem unreliable, nervous, and potentially deceptive to the jury. It is important to practice your examination questions with your witness to help them become more comfortable with being on the stand, questioned, and provide any necessary feedback to them as well regarding their actions or responses. It is also important to convey to the witness how they should act and to avoid these fidgety movements.
Conclusion
Understanding juror psychology is essential for any attorney to effectively persuade a jury. Jurors are human and as a result are subject to biases, cognitive limitations, and emotional influences. Their perceptions are shaped not only by the evidence presented but also by how that evidence is conveyed. Attorneys can create strategies that make their arguments clearer, more relatable, and more persuasive by being aware of pre-trial biases, cognitive processes, and the impact of language, tone, and body language. Clear communication, witness preparation, and awareness of jurors’ cognitive and emotional processing can help an attorney ensure that the jury understands the case and weighs the evidence in their favor. Ultimately, successful persuasion of the jury relies on an awareness of your words and language as well as the jury’s mind.
[1] Curley, LJ, Munro, J & Dror, IE, Cognitive and human factors in legal layperson decision making: Sources of bias in juror decision making, 62 Med. Sci. L. 206 (2022), https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9198394/
[2] Carlson, K. A., & Russo, J. E., Biased Interpretation of Evidence by Mock Jurors, 7 J. Experimental Psych.: Applied 91 (2001), https://doi.org/10.1037/1076-898X.7.2.91
[3] Curley, L. J., Munro, J., & Dror, I. E., Cognitive and Human Factors in Legal Layperson Decision Making: Sources of Bias in Juror Decision Making, 62 Med. Sci. & L. 206 (2022), https://pmc.ncbi.nlm.nih.gov/articles/PMC9198394/
[4] Heuristics, Psychology Today, https://www.psychologytoday.com/us/basics/heuristics (last visited Nov. 25, 2025).
[5] Curley, L. J., Munro, J., & Dror, I. E., Cognitive and Human Factors in Legal Layperson Decision Making: Sources of Bias in Juror Decision Making, 62 Med. Sci. & L. 206 (2022), https://pmc.ncbi.nlm.nih.gov/articles/PMC9198394/
[6] Curley, L. J., Munro, J., & Dror, I. E., Cognitive and Human Factors in Legal Layperson Decision Making: Sources of Bias in Juror Decision Making, 62 Med. Sci. & L. 206 (2022), https://pmc.ncbi.nlm.nih.gov/articles/PMC9198394/
[7] Id.
[8] Curley, L. J., Munro, J., & Dror, I. E., Cognitive and Human Factors in Legal Layperson Decision Making: Sources of Bias in Juror Decision Making, 62 Med. Sci. & L. 206 (2022), https://pmc.ncbi.nlm.nih.gov/articles/PMC9198394/
[9] Healy, Justice et al., Words Matter: How Attorney Language Abstraction and Emotional Valence Shape Juror Decision-Making, 15 Behav. Sci. 1355 (2025), https://pmc.ncbi.nlm.nih.gov/articles/PMC12562236/
[10] John P. Blumberg, The Psychological Science of Jury Persuasion, Plaintiff Magazine, Nov. 2017, at https://plaintiffmagazine.com/recent-issues/item/the-psychological-science-of-jury-persuasion
[11] Healy, Justice et al., Words Matter: How Attorney Language Abstraction and Emotional Valence Shape Juror Decision-Making, 15 Behav. Sci. 1355 (2025), https://pmc.ncbi.nlm.nih.gov/articles/PMC12562236/
[12] Id.
[13] Healy, Justice et al., Words Matter: How Attorney Language Abstraction and Emotional Valence Shape Juror Decision-Making, 15 Behav. Sci. 1355 (2025), https://pmc.ncbi.nlm.nih.gov/articles/PMC12562236/
[14] Courtroom Sciences, The Psychology of Body Language (n.d.),
https://www.courtroomsciences.com/litigation-consulting-1/the-psychology-of-body-language-605/ (last visited Nov. 25, 2025).
Recent Comments