Concept
Competency and Impaired Witnesses
Requirement of personal knowledge
Competency and Impaired Witnesses
Personal knowledge asks whether a witness perceived the particular fact she describes. A separate challenge goes to the witness herself: the opponent says she is too young, too ill, or too intoxicated to be heard at all. Rule 602 answers both questions together with its neighbors, Rules 601 and 603, and the three rules make up the entire modern test of competency, meaning a person's qualification to take the stand. The same group of rules also bars two particular people from testifying in their own trials, the presiding judge and a sitting juror. This section takes the general test first, then the impaired witness, then the judge and juror.
The Modern Competency Test
Rule 601 begins from inclusion: every person is competent to be a witness unless the rules provide otherwise.1 That starting point reverses a long history in which legislators and judges acted as gatekeepers and kept whole classes of people off the stand.2 The grounds of incompetency the rules do not recognize include age, mental incapacity, religious belief, conviction of a crime, and connection to the case as a party or interested person. Most of them survive only as ways of impeaching the witness.3 The old rules rested on judges' distrust of lay jurors, but excluding a witness who may be the only person who knows the facts costs the factfinder evidence it cannot get elsewhere.4 The modern rules therefore leave the weighing to the jury, working with cross-examination and cautionary instructions.
The only general competency requirements left are in Rules 602 and 603.5 Rule 602 allows testimony only if evidence is sufficient to support a finding that the witness has personal knowledge, and Rule 603 requires an oath or affirmation in a form designed to impress the duty of truthfulness on the witness's conscience.6 Read together, they ask four things: that the witness had the capacity to perceive, record, and recollect; that she in fact perceived something bearing on a fact of consequence; that she promises to tell the truth and understands the difference between truth and a lie or fantasy; and that she can understand questions and make herself understood, with an interpreter if needed.7 The sufficiency standard in Rule 602 is the same conditional-relevance standard used in Rule 104(b). The proponent need only offer evidence from which a reasonable juror could find that the witness perceived the matter.8 The judge screens, and the jury decides how far to believe her.
Courts and commentators read these rules in three ways, and the plain-text reading comes first. On that reading, Rule 601 leaves no competency standards beyond the oath and Rule 602, and the Advisory Committee's note supports it by stating that no mental or moral qualifications for testifying are specified.9 A conservative reading treats Rule 601 as creating only a presumption, so that the common-law capacity requirements survive and the judge must still find the witness qualified. That reading is weak, because the common law often already placed the burden on the opponent, and Rule 601 would then change almost nothing.10 An intermediate reading implies the four capacities listed above from Rules 602 and 603, but it applies the lenient Rule 104(b) procedure to all of them.11 The casebook critique of courts that read a mental-capacity requirement into Rule 602 or a moral-capacity requirement into Rule 603 rests on the text. Rule 602 asks only whether a reasonable juror could believe the witness perceived the matter, and Rule 603 asks only for an oath or affirmation.12 Under every reading, Rule 403 remains a backstop for an extreme case in which the testimony would be so garbled that it would only confuse the jury.13
Children, Mental Illness, and Addiction
Three groups are challenged as incompetent more often than any others: children, people with mental illness, and people addicted to drugs. None is excluded as a class. The question for each is whether the individual witness can recall what she claims to have perceived, can communicate it, and understands the duty to tell the truth.15 The common law had already moved this way. Children as young as three have been held competent, persons with deafness or muteness may testify, and even a crack cocaine user with the intelligence of a seven-year-old has been allowed to testify. A person is shut out only in extreme cases, such as insane delusions directly tied to the subject of the testimony.16
The case of McDuffie shows the rule applied to mental illness. A trial judge disqualified him as a witness, although he believed a figure he called Star Child had told him to kill someone. His treating physician testified that his memory was sufficient, that he understood the oath, and that he could communicate what he saw. The court of appeals held the disqualification improper, because the presumption of competence applies to a person considered insane to the same extent as anyone else. It also held the error was not harmless, because his testimony would have substantially corroborated the defendant's.17 Impairment tends to affect weight, which cross-examination exposes. The opponent may explore how age, retardation, injury, or mental illness affected the witness's ability to observe, remember, and recount. That inquiry is not collateral, so the opponent may offer extrinsic evidence of it.18 Drug use at the time of the event or at the time of testimony may be explored in the same way, and the witness's denial does not end the inquiry.19
A prosecution witness who admitted cocaine addiction shows the same point on the drug side. Defense counsel used cross-examination to expose his addiction, his claimed lack of memory, his uncertainty about details, and several inconsistencies, and the trial court called him a loose cannon. The court said his testimony alone would not support a guilty verdict, yet he was allowed to testify, and other circumstantial evidence supported the verdict. The appeals court noted that an earlier decision had rejected the claim that inconsistencies and addiction made this same witness incompetent.20 The weakness of his account lowered its value without keeping it from the jury. A similar contrast appears in California v. Green, where the witness Porter said he had taken LSD at the time of the events and could not remember them. The Court held that cross-examination, rather than the witness's memory, was the constitutionally critical factor under the Confrontation Clause.21 That is a confrontation holding, not a competency holding, but it reflects the same attitude toward impaired memory: the testimony is less reliable, and the jury weighs it.
The presumption can be rebutted at the extreme. Suppose a witness, after a head injury, cannot say what year it is and offers no coherent account of the events. If the evidence is viewed in the light most favorable to the proponent and no reasonable juror could believe that the witness perceived, recalls, and can narrate the matter, the testimony may be kept out. This is the standard sometimes called minimum credibility.22 Courts have also recognized that a witness's ability may be so impaired that she cannot satisfy Rule 602.23 Past lies are different. A child who has lied before is not barred, because there is no general bar on frequent liars. The opponent must instead point to the child's proven difficulty in separating truth from fantasy, which bears on personal knowledge and on the promise to tell the truth.24
Judges and Jurors as Witnesses
Two persons are barred from testifying as a matter of rule rather than capacity. The presiding judge may not testify as a witness at the trial, and a party need not object to preserve the issue.26 The reason follows from the judge's role. The person who rules on every objection cannot be cross-examined by the lawyers who must appear before her, and a jury is likely to give her factual statements more authority than any other witness's. A judge who supplies a fact from her own knowledge therefore puts into the case evidence that no party can effectively test. For this reason a judge's question that contradicts a witness, rather than clarifies the record, is treated as the equivalent of testifying.27
In United States v. Lewis, the trial judge found that a defendant's statements to agents were voluntary, and he said his finding was influenced by his own experience with the effects of general anesthesia after surgery. The court of appeals held that he was not a competent witness to the defendant's condition under Rule 605, and that no evidence showed he had personal knowledge of her actual condition under Rule 602.28 It also rejected the idea that judicial notice could rescue the finding. A judge may not use from the bench what she knows only as a private individual, and this judge had not announced any notice or relied on a generally known fact.29 Rule 602 is the second reason the judge could not supply the fact: her experience with her own surgery says nothing about what the defendant perceived or felt.
The juror rule works the same way. A juror may not testify as a witness before the other jurors at the trial, and if one is called, the court must give a party the chance to object outside the jury's presence.30 The rule exists for a reason like the judge's. A juror who testified would have to be evaluated by eleven colleagues who then deliberate with her. This rule is separate from Rule 606(b), which governs testimony about deliberations when a verdict is attacked later. That rule bars testimony about what happened in the jury room or about mental processes, with exceptions for extraneous prejudicial information, outside influence, and clerical mistakes on the verdict form.31
Children, Mental Illness, and Addiction
Three kinds of witness draw competency challenges more often than any others: children, people with mental illness, and people who use or are addicted to drugs. The rules do not exclude any of these groups as a class. The question in each case is about the individual witness: whether she could perceive the events, can remember them, can communicate them, and understands that she is obliged to tell the truth.33 The reason for refusing categorical bans is practical. A rule that shut out every child or every person with a psychiatric history would sweep in many people who saw the event clearly, and the factfinder would lose evidence it may be unable to get anywhere else. So the modern approach screens the individual witness for a minimum level of credibility and leaves the rest to cross-examination and the jury. Neither age nor sanity is itself the test of competency.34
Children show the principle most simply. Imagine a four-year-old who watched a neighbor's car strike a parked truck and who understands that she must tell the truth. Her youth is a reason for the jury to weigh her account with care, but it does not bar her from the stand. Before the modern rules, trial judges often held a preliminary hearing outside the jury's presence to test a child, an alleged addict, or a mentally impaired witness, and courts still routinely hold such hearings. The judge may receive expert testimony at them and may order a psychiatric examination to help decide whether the witness qualifies.35 Change one fact and the result changes. Suppose a different child cannot tell what she actually saw from what she imagined. If a reasonable juror, viewing the evidence in the light most favorable to the proponent, could not believe that this child observed, remembers, and can narrate the event, her testimony may be kept out.36 What moved the answer was not her age but the absence of any reasonable basis for crediting her perception.
Mental illness follows the same logic. A finding that a person is feebleminded, a period spent in a mental institution, and even a determination that the person was incompetent to stand trial do not by themselves make the person incompetent as a witness, because mental deficiency ordinarily affects the weight of testimony rather than its admissibility.37 The McDuffie episode, decided in the Fourth Circuit, shows how far the presumption of competence reaches. McDuffie believed that a figure he called Star Child had told him to kill a man, and the trial court disqualified him as a witness. His treating physician testified that his memory was adequate, that he understood the oath, and that he could communicate what he had seen. On that record the court of appeals held the disqualification clearly improper, because the presumption of competence applies to a person considered insane just as it applies to anyone else.38 The error also required a new trial, since his testimony would have substantially corroborated another witness's account.39 A delusion on one subject, in other words, did not disqualify him on the events he actually observed.
Addiction raises the question whether a witness's impairment goes to admissibility or to weight, and the answer is usually weight. In the Hickey prosecution, a government witness named Ventimiglia was a self-confessed cocaine addict whom the trial judge called a loose cannon. On cross-examination, defense counsel exposed his addiction, his claimed lack of memory, his uncertainty about details, and several inconsistencies in his story.40 The Sixth Circuit nonetheless held that he was properly allowed to testify. Its reasoning rested on the low threshold of Rule 602: testimony should be excluded for lack of personal knowledge only if no reasonable juror could believe that the witness had the ability and opportunity to perceive the events he described.41 The same court recognized that a witness's ability can be so impaired that he cannot satisfy the rule, but this witness was not in that position, because a rational juror could believe he perceived the course of events despite finding much of his account unconvincing.42 The defense had the remedy it needed in cross-examination, which let the jury see every weakness in his account.
A witness whose memory has failed can still be heard, as the facts of California v. Green show. The State's main witness, a young man named Porter, testified that he had taken LSD about twenty minutes before the telephone call at the center of the case and could not remember what followed. He added that the drug had kept him from distinguishing fact from fantasy, and the trial court described him as markedly evasive.43 After the prosecutor read his earlier hearing testimony to him, Porter guessed that he had obtained the marihuana from the defendant's parents' yard, but on cross-examination he conceded that what had been refreshed was his memory of the earlier testimony, not of the events themselves.44 The Supreme Court's holding concerned the Confrontation Clause: it rejected the California court's view that cross-examination at trial and at the preliminary hearing was an inadequate substitute for confrontation.45 It is therefore not a competency decision. Even so, the case shows a witness with a drug-clouded memory taking the stand and being tested by questioning, with the weakness of his account left for the factfinder to assess.
The presumption of competence has limits, and they define the point at which a witness is excluded. The ultimate question is whether the witness is so lacking in the powers of observation, recollection, and narration, or in understanding of the duty to tell the truth, that no reasonable juror could believe him. A witness that deficient lacks minimum credibility, and his testimony may not be received.46 Rule 403 stands behind that screen. A witness who barely clears it may still be excluded when his deficiencies are so severe that the probative value of his testimony is outweighed by the dangers Rule 403 lists, and the more deficient the witness, the more likely that outweighing becomes.47 A witness who passes both screens is subject to cross-examination on his ability to observe, remember, and narrate and on his understanding of the duty to testify truthfully. Because that inquiry bears on credibility, the opponent may offer extrinsic evidence of the impairment.48 The sequence is a low screen, then Rule 403 for the extreme case, then cross-examination for everything else.
Judges and Jurors as Witnesses
Two participants in a trial are barred from testifying in it by categorical rule, without any inquiry into what they actually know. The presiding judge is one, and a sitting juror is the other. Both bars connect to the personal knowledge requirement, because each person occupies a position in which private knowledge can enter the case without the safeguards that ordinarily attach to testimony.
Rule 605 provides that the judge presiding at a trial may not testify in that trial as a witness, and that no objection need be made to preserve the point.50 The automatic character of the objection follows from the problem it addresses. A judge cannot act as an impartial referee and as a source of evidence at the same time. The lawyers who must appear before her every day are poorly placed to cross-examine her, and a jury is likely to give a factual statement from the bench more weight than the same statement from any other witness. Because the judge's own conduct is the difficulty, no party can be expected to raise it, and the rule works without an objection.51 The disqualification also reaches a judge who never takes the stand. If she injects facts from her private knowledge that are not judicially noticeable, she has in effect become a witness, and her conduct is objectionable under Rule 605.52
The bar is tied to the trial before her. Suppose an assault occurs in a courtroom during a trial. The judge who saw it may testify in the later assault prosecution, because a different judge presides there and her office does not disqualify her from testifying in a case she is not trying.53 The facts she perceived are the same in both settings. Only her role changes, and the rule follows the role.
The bar and the personal knowledge requirement operate together when a judge reasons from private experience. In United States v. Lewis, a trial judge found that a defendant's statements to agents were involuntary, and he acknowledged that his finding was influenced by his own experience of recovering from surgery under general anesthesia and by what others had told him about his behavior afterward.54 The court of appeals reasoned that, had he been sworn as a witness on that subject, his testimony would have been incompetent twice over: he was the presiding judge, and nothing showed he had personal knowledge of the defendant's actual condition when she spoke.55 What he felt after his own operation said nothing about what she perceived or understood on the day in question. In substance he had testified without an oath and without cross-examination.
Lewis also rejected the argument that judicial notice could save the finding. A judge may not use from the bench what she knows only as a private observer, and this judge had neither announced that he was taking notice nor relied on a fact generally known or readily verifiable from reliable sources under Rule 201(b).56 Announcement matters because it gives a party the opportunity to be heard on whether notice is proper and on what is being noticed.57 The contrast case shows the difference. In Bey v. Bolger, a court took notice, in a written memorandum setting out its basis, that hypertension makes a person susceptible to stroke or heart attack, so the parties could ask for reconsideration, and the judge did not rely on his own experience of the condition.58 In Lewis, by contrast, the prosecutor could not compare the judge's illness and dose with the defendant's abscessed shoulder, or test the judge's opinion in any other way the adversarial system uses to assure trustworthiness.59
The juror rule is the counterpart of Rule 605. Under Rule 606(a), a juror may not testify as a witness before the other jurors at the trial, and if one is called, the court must give a party the chance to object outside the jury's presence.60 The reasoning parallels the judge's. A juror who testified would be a witness whose credibility the other eleven must assess while they also deliberate with him, and the lawyers could hardly cross-examine someone who will then vote on the verdict. The phrase "before that jury" matters: the rule does not prevent the judge or counsel from questioning prospective jurors during selection.61 In practice a prospective juror who admits to knowing about the events is excused during selection, so a juror ever reaches the stand only rarely.62
Rule 606(a) should be kept apart from Rule 606(b), which applies later and concerns a different problem. Rule 606(b) governs an inquiry into the validity of a verdict or indictment and bars a juror from testifying about statements or incidents in deliberations, the effect of anything on any juror's vote, or any juror's mental processes. Exceptions allow testimony on extraneous prejudicial information, outside influence, and a mistake in entering the verdict.63 The first rule asks whether a juror may be a witness during the trial. The second asks what jurors may say afterward to attack the result.