A thorough study of the development of our jury system might surprise you.  

Today, we bend over backwards to ensure a juror knows nothing about a case before being selected to be a juror.   

"Medieval juries were self-informing, in that individuals were chosen as jurors because they either knew the parties and the facts, or they had the duty to discover them. This spared the government the cost of fact-finding.  Over time, English juries became less self-informing and relied more on the trial itself for information on the case. Jurors remained free to investigate cases on their own until the 17th century."