Date of Award

January 2019

Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Andre Kehn


To prevent the biasing influence of information obtained outside of the courtroom courts often issue instructions to jurors that limit or prohibit certain activities and the use of information during the trial and when making verdict decisions. (i.e., prohibitive instructions). However, research indicates that mock jurors tend to ignore such instructions. Additionally, advances in mobile technology give today’s jurors easier access to potentially biasing information obtained through the internet and digital communication (e.g., social media, blogs, email, and texting). This raises the question not yet addressed by extant research, whether jurors access this information during a case, even when judges issue instructions prohibiting such activities. To investigate this question 208 mock jurors participated in a two-stage mock jury trial. They viewed and listened to narrated transcripts from a real murder case and deliberated as a jury. Mock jurors were given one of three judicial instructions that either prohibited internet-based juror misconduct (IBJM) with reasons and consequences (strong), only prohibited IBJM (weak), or did not mention IBJM (control). The results show that instructions currently recommended in Federal courts (weak) did not prevent IBJM more effectively than those without the admonishment. However, significantly lower rates of IBJM were found among mock jurors administered the strong instructions than the weak or control instructions. Last, the Juror Internet Research Scale (JIRS) did not identify or predict non-compliant mock jurors who engaged in IBJM. Implications of these findings for instruction literature and theory are discussed as well as potential impacts on the court system.