Dateline: September, 2007, Issue 5
Because of the nearly unrestricted use of leading questions, cross-examination provides opportunity to influence jurors through questions designed to impart information to the jury.
Kassin and colleagues (1990) tested whether jurors' perceptions of an expert witness can be influenced by leading cross-examination questions. Jurors heard a cross-examiner ask two questions of an expert witness that implied something negative about the reputation of that expert (Isn't it true that your work is poorly regarded by your colleagues? Hasn't your work been sharply criticized in the past?). One third of these jurors also heard a denial from the expert (No, it isn't; No, it hasn't), one third heard an admission from the expert (Yes, it has; Yes), and one-third heard objections to the questions from an attorney that were sustained by the judge and then withdrawn before the witness had a chance to respond. There was also a group of jurors who did not hear the leading cross-examination questions.
The expert's credibility - that is, the expert's honesty, believability, competence and persuasiveness - was significantly diminished by the leading questions. The expert was less credible to jurors even when the expert flatly denied the charge or the attorney won a favorable ruling on an objection.
The researchers concluded that the technique of cross-examination by innuendo is highly effective in diminishing an expert's credibility, and that both an attorney's objections and an expert's denials of the innuendo fall on deaf ears.
Source Kassin, S. M., Williams, L. N., & Saunders, C. L. (1990). Dirty tricks of cross-examination. Law & Human Behavior, 14, pp. 373-384.