There are (at least) two problems possibly stemming from a person testifying in court:

  • If they tell the truth, the testimony may have negative consequences they potentially don't like (which is the whole point of 5th Amendment, when the testimony is by the accused or in general detrimental to person testifying).

  • If they lie, they can be convicted of perjury, which is a nice fallback when you don't care about actual crime but about getting the person damaged at least somehow - US history and especially politics is littered by people who were gotcha-ed by perjury charges and not main charges.

If that is the case, then what prevents such a person from simply saying "I do not remember" when testifying? You can't prove a negative, so they can't be convicted of perjury for lying about whether they remember; they didn't testify about any fact so they can't perjure themselves; and they didn't help the prosecution (or defense) by truth.

  • Comments have been moved to chat; please do not continue the discussion here. Before posting a comment below this one, please review the purposes of comments. Comments that do not request clarification or suggest improvements usually belong as an answer, on Law Meta, or in Law Chat. Comments continuing discussion may be removed.
    – feetwet
    Commented Apr 10, 2023 at 0:34

6 Answers 6


You can't prove a negative, so they can't be convicted of perjury for lying about whether they remember;

Yes, they can. The government can convict the witness of perjury by proving that they did remember. This may be difficult, but it's not impossible.

Now you may say that we can't ever prove with certainty what a person did or didn't remember. But the legal standard isn't certainty, it's beyond a reasonable doubt. So a jury is allowed to draw a reasonable inference about whether they remembered, based on evidence of their outward behavior and other circumstances.

As an extreme example, suppose Alice was overheard chatting freely about topic X an hour before the trial, but when asked about topic X on the stand, said she didn't remember. When presented with evidence of her earlier conversation, a jury could reasonably infer that she was lying about not remembering. Is it possible that she truly had a memory lapse in the intervening hour? Sure, anything is possible. Is it reasonable to believe that she did? Probably not.

The US Department of Justice's Criminal Resource Manual has this to say on the subject:

Witnesses who claim not to remember, rather than deny a fact, may be prosecuted for perjury. However, the government must prove both that the witness at one time knew the fact and that the witness must have remembered it at the time he or she testified. United States v. Chen, 933 F.2d 793, 795 (9th Cir. 1991). If the dates of the transaction and testimony are sufficiently close, memory may be inferred. Instances in which the witness remembered other events that occurred at the same time or earlier than the event in question, or mentioned the event either immediately before or after his testimony, would be probative of the witness's memory at the time of the testimony. The two witness rule does not apply to prosecutions based on false memory lapses, and circumstantial evidence is sufficient, since there is no direct evidence possible concerning what the defendant actually believed. Gebhard v. United States, 422 F.2d 281, 287 (9th Cir. 1970).

There's a similar issue in all laws that deal with a person's knowledge or intent. Suppose Alice hits Bob with a stick and he dies. To convict Alice of murder, it must be proved that by hitting Bob, she intended to kill him. Can we ever really know what was in her heart? Maybe not, but if there is evidence that shortly beforehand, she told someone that she was going to kill Bob, it would be a reasonable inference that this was her intention.

  • 25
    In practice, it is sometimes not all that difficult to show that "I don't remember" is false because people sometimes go overboard. I've seen people denying that they know where they live, who they are married to, who is depicted in a picture of their children, whether they've recently been the victim of a gunshot wound . . . while clearly displaying no signs of dementia.
    – ohwilleke
    Commented Apr 6, 2023 at 21:10
  • 2
    @Barmar Hearsay is second-hand. If Alice tells Charlie that she's going to kill Bob, Charlie's testimony in court about that statement is not hearsay. If Charlie says to Danielle in a bar "Alice told me she was going to kill Bob", Danielle's testimony in court would be hearsay, because she's testifying not about what Alice said, but about what Charlie said Alice said. Commented Apr 7, 2023 at 16:50
  • 2
    @Barmar Yes, that's right; Charlie could also not testify "Alice killed Bob" or "Alice wanted to kill Bob"; what Charlie can say is "Alice said to me 'I'm going to kill Bob'". Commented Apr 7, 2023 at 16:53
  • 10
    What about a claim that you do remember, but don't think you remember well enough to testify under oath? If you ask me privately what I had for dinner two weeks ago, I remember well enough to answer you. If you swear me in and order me to answer truthfully under pain of perjury...well, I really do not remember to that level of certainty. And I am not sure that I remember just about anything to a degree of certainty high enough to defeat a prosecutor determined to set up a perjury trap.
    – tbrookside
    Commented Apr 7, 2023 at 19:21
  • 1
    I'd add that this could also apply in civil lawsuits - the case where Alex Jones was heavily shown to be lying about Sandy Hook discovery had him claiming "We couldn't find any texts with the words 'Sandy Hook', if we did have them, even when I did search for them." - even if he didn't remember the evidence shortly followed up with, it's proof that he should have found it during a routine search. Commented Apr 7, 2023 at 23:51

Anything you say in a court of law can be used against you in a court of law, unless the testimony is given under a grant of immunity. You would need to provide a transcript of the hypothetical testimony to get the understanding that you're looking for, but it is easy for a person to contradict themselves, claiming that you saw Jones on some date, and that you can't remember if you have ever seen Jones. Your "can't remember Jones" testimony can be refuted with physical evidence such as emails, journal entries, photographs or testimony such as a person testifying that they saw you talking to Jones in a manner that clearly indicates that you knew who he was.

You might avail yourself of the brain-surgery defense, to the effect that you may have done so but in the interim you had brain surgery and you can't remember anything from that month, but the jury will not believe that unless you provide convincing positive evidence that you had such surgery and that there is sufficient medical reason to believe that lack of recollection is possible.

Although this is not ideally how it is supposed to play out, if the prosecution offers some reason to think that you lied on the stand, you have to offer a reason to doubt the prosecution's position. In some jurisdictions, the finders of fact are told that they should be "firmly convinced" of the prosecution's claim, but there is a real tendency for juries to understand "reasonable doubt" as referring to "a reason to doubt". That is how you "prove a negative", by offering evidence that contradicts the claim.


Nothing stops a person from saying just that. Ronald Reagan famously did so when subpoenaed during Iran-Contra.


It was widely regarded as a dodge at the time. On the other hand he was diagnosed with Alzheimer's a few years later. (But on the gripping hand, his doctors say he didn't start showing signs of that until 1993. https://www.baltimoresun.com/news/bs-xpm-1997-10-05-1997278112-story.html So maybe it was a dodge.)

Other answers here have give reasons that doesn't always work. But this famous precedent seems relevant.


What stops them from claiming they don't remember? Not much can stop them from doing it. But there can be repercussions. Another poster rightfully pointed out that someone CAN be convicted of perjury for claiming they couldn't remember something. And even if the witness is never charged and prosecuted for perjury, the judge or jury is entitled to take everything the witness says (including claims that they can't remember something) into account when deciding whether they believe what the witness is saying. If the facts and circumstances lead a judge or jury to doubt that the witness is telling the truth about being unable to remember, they might give the testimony of this witness (including unrelated things testified to by the witness) less weight because they doubt the witness's credibility. And if the witness tries to later claim that they now remember the information they previously claimed to be unable to remember, that can similarly impact their credibility.


At the end of the day, if a witness persists in saying "I don't remember" and there is good reason they may be lying, the prosecution can always call an expert witness (say a psychologist who specializes in the subject of memory) who would give their expert opinion on whether or not the witness could be genuinely as forgetful as claimed.

The circumstances do matter. If asked "what did you do on a specific date, exactly ten years ago" most people would claim that they do not remember. And that is rather unlikely to be challenged. If you're asked "what did you do yesterday evening" and you say you don't remember because you were totally drunk, you do have arguments on your side ("Blackout"), assuming there is genuine objective evidence that you were totally drunk. But if you're asked "what did you do two days ago" and you're neither a drunkard nor an amnesiac, then the statement "I just don't remember" carries so much less weight.


Indeed it is usually not advantageous to testify in court. For most potential witnesses the smart thing to do is to say less.

However, some witnesses are special. For example, a store's loss prevention officer may be motivated to testify. The LP witness will testify against the alleged shop lifter. The LP witness will under direct examination explain to the jury why they should also think the alleged shop lifter is a scoundrel. This is friendly questioning. The LP witness does not have to worry. If there is some aspect that the LP witness does not want to visit, the plaintiff will not go there.

In return, the alleged shop lifter's side gets to ask questions of the LP witness. The safest course of action is for the LP witness to do as you say and "not remember." However the jury is allowed to make judgements. If for the plaintiff the LP witness has amazing memory and for the defendant the LP witness forgets a shocking amount, then the jury can draw their own conclusions.

Maybe the LP witness did not really have such an amazing memory but made stuff up and lied. Maybe the LP witness did not really forget but chose to "not remember." Either way, undercuts the testimonial power of the LP witness.

But you or I do not care about such things. Maybe you were at the store at the time of the alleged shop lifting incident. Maybe you were in the vicinity. Maybe you witnessed it. You probably forgot because it is not that important to you. Even if you remembered you probably have better things to do than testify in court. If nonetheless you are still in court, the outcome makes no difference to you. Testifying can only hurt you, never help you.

If you are put up to the stand, the jury will know who forced you on the stand, and you will repeatedly not testify and the jury will think whoever forced you on the stand wasted their time. So you will probably not be forced on the stand.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .