RULE 606(B) PROVIDES THAT JURORS MAY NOT TESTIFY ON ANY MATTER OCCURRING DURING THE JURY'S DELIBERATIONS THAT MIGHT HAVE AFFECTED THE VERDICT OR INDICTMENT UNLESS THERE WAS EXTRANEOUS PREJUDICIAL INFORMATION IMPROPERLY BROUGHT TO THE JURY'S ATTENTION OR SOME OUTSIDE INFLUENCE OR PRESSURE INTERFERED WITH THE OUTCOME OF THE JURY'S DECISION. THE COMMON LAW ANTECEDENT AND RATIONALE OF THE EXCLUSIONARY DOCTRINE ARE DESCRIBED AS WELL AS THE EVOLUTION OF RULE 606 (B) FROM ITS EARLY DRAFT BY THE ADVISORY COMMITTEE OF THE HOUSE OF REPRESENTATIVES TO ITS ADOPTION BY CONGRESS. INSTANCES IN WHICH THE RULE IS APPLICABLE INCLUDE SITUATIONS IN WHICH ONE OR MORE JURORS HAVE IGNORED OR MISUNDERSTOOD INSTRUCTIONS OR INTERROGATORIES OR APPLICABLE SUBSTANTIVE LAW, ONE OR MORE JURORS COMPROMISED PRINCIPLES OUT OF CONCERN OVER PERSONAL MATTERS IN ORDER TO MAKE AN EARLY END TO DELIBERATIONS, OR WHEN A JURY AGREED ON A TIME LIMIT FOR DELIBERATIONS. CASES ILLUSTRATING EXCEPTIONS TO THE RULE INCLUDE SITUATIONS IN WHICH ONE OR MORE JURORS HAVE CONDUCTED EXTRARECORD INVESTIGATIONS INTO THE CONTROVERSY INVOLVED DURING DELIBERATIONS OR WHEN INFORMATION WHICH COULD INFLUENCE DELIBERATIONS HAS BEEN RECEIVED IN THE JURY ROOM BY WAY OF MEDIA. SITUATIONS IN WHICH VERDICTS ARE SET ASIDE OR ALTERED BUT IN WHICH RULE 606 (B) DOES NOT APPLY ARE ALSO CONSIDERED, AS WELL AS PROCEDURAL PROBLEMS INVOLVING JUROR INTERVIEWS, MOTIONS, HEARINGS, AND BURDEN OF PROOF THAT AFFECT IMPEACHMENT OF JURY VERDICTS. (DAG)