ALL POTENTIAL PARTICIPANTS WERE GIVEN ATTITUDINAL QUESTIONNAIRES AND EQUAL NUMBERS OF PERSONS PREDISPOSED TOWARD CONVICTIONS OR ACQUITTAL WERE CHOSEN. IN THE FIRST TWO EXPERIMENTS A TOTAL OF 24 MOCK JURORS READ ACCOUNTS OF TRAFFIC FELONY CASES. IN SOME INSTANCES THE FACTS WERE PRESENTED AS RELIABLE, IN SOME AS BEING OF DOUBTFUL VALIDITY, AND IN SOME NO EVALUATION WAS MADE. HARSHER JURORS ASSIGNED MORE GUILTY RANKINGS AND LENIENT JURORS MORE ACQUITAL RANKINGS WHEN THE EVIDENCE WAS PRESENTED AS UNRELIABLE OR WAS NOT RATED. HOWEVER, WHEN THE FACTS WERE PRESENTED AS RELIABLE AND AGREED TO BY BOTH THE PLAINTIFF AND THE DEFENDANT, THE JUDGMENTS REFLECTED THE EVIDENCE. AN ADVERSARY TRIAL IN WHICH EACH SIDE ATTEMPTS TO DISCREDIT THE VALIDITY OF THE EVIDENCE MAY ACTUALLY ACCENT JUROR PREJUDICE, INSTEAD OF MITIGATING IT. ON THE OTHER HAND, THE EUROPEAN SYSTEM WHICH USES AN IMPARTIAL FACT-FINDING MODE MAY OVERCOME THIS NATURAL PREJUDICE. IN THE THIRD EXPERIMENT MOCK JURY TRIALS TESTED THE EFFECTS OF BIAS AGAINST VARIOUS COURTROOM PARTICIPANTS. A 15-MINUTE TRIAL WAS EXTENDED TO 50 MINUTES BY IRRITATING AND OBNOXIOUS BEHAVIOR BY EITHER THE DEFENSE ATTORNEY, THE PROSECUTOR OR THE JUDGE. GREATEST GUILT WAS ATTRIBUTED TO THE DEFENDANTS WHEN THEIR ATTORNEYS WERE ANNOYING, THE LEAST GUILT WHEN THE PROSECUTORS WERE ANNOYING OR THERE WAS NO ANNOYANCE. THIS BIAS, HOWEVER, WAS MEDIATED BY THE FACTS OF THE CASE. TABLES PRESENT THE STUDY DATA, WHICH IS DISCUSSED AT LENGTH. REFERENCES ARE APPENDED. (GLR)