Researchers have proposed many explanations for the replicated finding that jurors often fail to disregard evidence when instructed by a judge to do so. We propose a novel explanation: that the act of objecting may cause the effect because an objection (a) draws attention to the testimony and (b) heightens the perceived importance of the testimony (because of the implication that the objecting party wants to prevent jurors from using it). In previous studies, the act of objecting has always been confounded with the presence of the critical (objected-to) testimony. We devised two new experimental conditions that unconfound these factors. We found that whereas objections increase the use of objected-to (incriminating) testimony, random (non-objection) interruptions decrease use of this testimony. We conclude that, unlike random interruptions, an objection communicates to the jurors that an attorney is concerned about the objected-to testimony, increasing the perceived importance of that testimony.
Wilson, Molly J. Walker and Spellman, Barbara A. and York, Rachel, Beyond Instructions to Disregard: When Objections Backfire and Interruptions Distract (May 3, 2014).