Jury: Behavioral Aspects

Trials increasingly involve the testimony of experts who present technical and scientific evidence. The addition of DNA evidence to the usual range of forensic testimony is a prime example. Surveys of jurors indicate that they find expert testimony to be useful, but they are wary of experts and their potential biases, a factor that can affect an expert's persuasiveness. Jurors typically work hard at trying to understand the content of expert testimony. Motivation, however, is not enough to ensure success and jurors often express concern about their ability to handle complex evidence.

Jurors are instructed to base their verdicts on the evidence presented at trial and legal instructions. However, their ability to fully process the evidence may be reduced if the expert fails to teach as well as attempt to persuade. When faced with technical testimony, jurors look for cues about the trustworthiness of the source, sometimes using the language itself as a cue. When a decision-maker accepts a persuasive message in response merely to cues (e.g., the prestigious credentials or complicated language of the source of the message), and has not processed and evaluated the message itself, the decision-maker is engaging in peripheral (or heuristic) processing. This approach contrasts with the central (or systematic) processing of the expert testimony that occurs if there is a thorough evaluation of the evidence.

There is little evidence to suggest that jurors adopt the position of an expert based solely on peripheral cues. What is more likely to happen is that the juror will reject unintelligible expert testimony. Moreover, unintelligible jargon may lead jurors to give less credence to an expert who displays other evidence of potential bias, such as an unusually high rate of pay.