Dateline: October, 2010, Issue 1
The study of the influence of inadmissible evidence on jurors, and admonitions to disregard it, has spanned more than 30 years.
Steblay and colleagues (2006) conducted a comprehensive review of this research, and examined 175 different tests of the effects of instructions to disregard inadmissible evidence that were reported in 48 different studies.
Conviction rates were higher when jurors were exposed to the inadmissible evidence and an admonition, than when jurors did not hear the inadmissible information.
Jurors exposed to the inadmissible evidence who received an admonition also convicted more often than jurors exposed to the inadmissible evidence who did not receive an admonition.
Jurors were particularly susceptible to being influenced by stricken evidence when a reason for rejecting the evidence was not provided, the evidence was rejected due to an unexplained technicality, or the rejected evidence was obtained illegally.
In sum, jurors are reluctant to disregard inadmissible evidence that they consider probative, and judicial instructions do not eliminate jurors' use of stricken evidence.
Source Steblay, N., Hosch, H., Culhane, S. E., & McWethy, A. (2006). The impact of juror verdicts of judicial instruction to disregard inadmissible evidence: A meta-analysis. Law and Human Behavior, 2006, pp. 469-542.