Presentation of evidence - Ability to observe, remember, or ...

Learning Outcomes

This article explains the foundational requirements for witness testimony under the Federal Rules of Evidence, focusing on how a witness’s ability to observe, remember, and relate accurately affects competency determinations on MBE-style questions, including:

• Identifying the core components of witness competency under FRE 601–603 and how they interact with personal knowledge.
• Applying the personal knowledge requirement of FRE 602 to fact patterns involving limited opportunity to observe, sensory impairments, or intoxication.
• Distinguishing memory weaknesses that merely undermine credibility from those that negate competency and bar testimony altogether.
• Using FRE 612 and FRE 803(5) to address memory problems through present recollection refreshed and past recollection recorded without rendering a witness incompetent.
• Analyzing how the oath or affirmation, a witness’s understanding of the duty to tell the truth, and practical communication abilities relate to accurate narration of events.
• Evaluating when language barriers, interpreters under FRE 604, or other communication difficulties create true competency issues versus arguments that only affect the weight of the evidence.
• Separating genuine competency objections from credibility-focused attacks so as to select the correct admissibility outcome on bar exam multiple-choice questions.

MBE Syllabus

For the MBE, you are required to understand witness competency and the presentation of testimonial evidence, with a focus on the following syllabus points:

• General rule of witness competency in federal court (FRE 601), including the role of state law in civil diversity cases.
• Personal knowledge requirement for lay witnesses (FRE 602), including what counts as sufficient evidence of perception.
• Oath or affirmation requirement (FRE 603) and its relationship to truth-telling.
• Distinction between witness competency (ability to observe, remember, and relate under an oath) and credibility (weight and believability of testimony).
• Use of related rules (FRE 612 and FRE 803(5)) to deal with memory problems without rendering a witness incompetent.
• Role of interpreters (FRE 604) and communication difficulties in assessing a witness’s ability to relate accurately.

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

1. Under the Federal Rules of Evidence, a lay witness may testify to a matter only if:
   1. The witness has specialized knowledge about the matter.
   2. Evidence is introduced sufficient to support a finding that the witness has personal knowledge of the matter.
   3. The witness is an adult of sound mind.
   4. The witness's testimony is undisputed.
2. A witness testifies at trial about a car accident she saw last year. On cross-examination, the opposing counsel asks, "Isn't it true you were treated for significant memory loss shortly after the accident?" This question primarily challenges the witness's ability to:
   1. Observe accurately.
   2. Remember accurately.
   3. Relate accurately.
   4. Understand the oath.
3. Which element ensures a witness appreciates the duty to testify truthfully?
   1. Personal knowledge.
   2. Competency hearing.
   3. Oath or affirmation.
   4. Relevance of testimony.

Introduction

For evidence to be presented through a witness at trial, the witness must be deemed competent to testify. Competency involves several foundational requirements related to the witness's capacity to provide reliable information. Central to this is the witness's ability to have observed an event, remember it, and then accurately relate it to the trier of fact, all under the solemnity of an oath or affirmation. The Federal Rules of Evidence (FRE) adopt a generally liberal approach to competency, presuming witnesses are competent unless specific rules provide otherwise.

The MBE often tests this area by giving you a witness with problems—poor eyesight, intoxication at the time of the event, past head injury, limited English, young age, or deep bias—and asking whether the testimony is admissible. Your task is to decide whether the issue is:

• A genuine competency problem that bars the witness from testifying at all; or
• A credibility issue that merely affects how much weight the jury gives the testimony.

Under the Federal Rules, true incompetency is rare. Most weaknesses in a witness’s perception, memory, or communication are for the jury, not the judge, to evaluate.

Key Term: Competency
The legal qualification of a person to give testimony in court, based on their ability to observe, remember, relate events, and understand the duty to tell the truth.

Key Term: Personal Knowledge
Knowledge derived from a witness's own direct sensory perceptions—what the witness actually saw, heard, smelled, touched, or tasted, as opposed to speculation or repetition of someone else’s statements.

Key Term: Oath or Affirmation
A solemn promise to testify truthfully, administered in a form calculated to awaken the witness’s conscience and impress upon them the duty to tell the truth.

Key Term: Ability to Observe
A witness’s capacity and actual opportunity to perceive the events or conditions about which they are testifying through their senses.

Key Term: Ability to Remember
A witness’s capacity to retain and recall information about events they previously perceived, at least to the extent necessary to give meaningful testimony.

Key Term: Ability to Relate
A witness’s capacity to communicate their perceptions and memories in a way the fact-finder can understand, whether verbally, through sign language, or with the aid of an interpreter or other accommodations.

Key Term: Interpreter
A qualified person who translates testimony or questions for a witness who cannot communicate effectively in the language of the court; under FRE 604, interpreters must take an oath to make a true translation.

Key Term: Credibility
The degree to which a witness’s testimony is believable and reliable; assessed by the fact-finder and influenced by factors like perception, memory, bias, and demeanor, but usually not a basis for exclusion.

General Framework: The Four Basic Testimonial Abilities

Traditional evidence doctrine breaks witness competency into four core abilities:

• Ability to observe (perception).
• Ability to remember (memory).
• Ability to relate (communication).
• Ability to appreciate the obligation of the oath or affirmation (understanding the duty to tell the truth).

The Federal Rules embed these concepts in three provisions:

• FRE 601 (general competency).
• FRE 602 (personal knowledge, which presupposes observation and some memory).
• FRE 603 (oath or affirmation, which is tied to the ability to relate truthfully).

On an MBE question, think in this order:

1. Does any Rule disqualify the witness (competency)?
2. Does the witness have at least minimal personal knowledge of the matter (observation + memory)?
3. Can the witness understand and accept the duty to tell the truth and communicate what they know (relate accurately under an oath)?

If the answer to all three is yes, the witness is competent. Weaknesses in any of these areas are then classic cross-examination material and go to credibility, not admissibility.

General Rule of Competency (FRE 601)

FRE 601 establishes a broad presumption: "Every person is competent to be a witness unless these rules provide otherwise." This rule sweeps away many traditional common law grounds for disqualification (for example, religious belief, conviction of a crime, direct financial interest in the lawsuit, or being a party).

For the MBE, assume a witness is competent unless:

• A specific Federal Rule disqualifies them (which is rare); or
• In a civil case under diversity jurisdiction, state law supplies the rule of decision and a state competency rule (often a Dead Man’s statute) applies under FRE 601’s second sentence.

The core assessment under the FRE focuses not on categorical disqualifications but on the fundamental abilities necessary for testimony: observation, memory, communication, and understanding the obligation to be truthful. A witness with mental illness, a criminal record, bias, or substance abuse history is generally still competent; those factors almost always go to credibility, not competency.

Most competency issues are resolved by the judge as preliminary questions under FRE 104(a). The judge may briefly question the witness (often outside the jury’s presence) to decide whether the minimum standards are met.

Personal Knowledge Requirement (FRE 602)

A key component of witness testimony is the requirement of personal knowledge. FRE 602 states that a witness may testify to a matter only if evidence is introduced sufficient to support a finding that the witness has personal knowledge of the matter.

Evidence of personal knowledge can come from:

• The witness’s own testimony (e.g., “I saw…”, “I heard…”); and
• Occasionally, other evidence (such as a surveillance video showing the witness at the scene).

The standard is low: “sufficient to support a finding” that the witness perceived the matter. The judge does not decide that the witness is right—only that a rational juror could conclude the witness has personal knowledge.

Ability to Observe

The personal knowledge rule directly relates to the witness's ability to observe the events or conditions about which they are testifying. The witness must have perceived the matter through their own senses.

• Prerequisite: The party offering the witness must provide a basis showing the witness had an opportunity to observe the event. This is often established through the witness's own testimony (e.g., "I was standing on the corner and saw the collision").
• Obvious failures of observation (e.g., the witness was unconscious, asleep, in another city, or physically unable to perceive, such as a blind person describing visual details) will defeat personal knowledge and make the testimony inadmissible as to that matter.
• More commonly, limitations on observation—poor lighting, a brief glance, distance, intoxication, stress, or impaired senses—do not defeat competency. They are explored during cross-examination to attack credibility, not competency.

For MBE purposes, if the facts show the witness had some opportunity to perceive the event, the testimony should be admitted; the weaknesses are for the jury.

Worked Example 1.1
At trial for robbery, the prosecution calls a witness who was inside the bank during the event. The witness states, "I was terrified and mostly hid under a desk, but I peeked out and saw a person with a red jacket run out." On cross-examination, the defense establishes the witness only peeked for a split second and admits his view was partially obscured. The defense moves to strike the testimony for lack of competency. How should the court rule?

Answer:
Deny the motion. The witness has personal knowledge based on direct observation, even if limited. The limitations (brief view, partial obstruction, fear) go to the weight and credibility of the identification testimony, which the jury should assess, not to the witness's basic competency to testify under FRE 601 and 602.

Lay opinions and observation: FRE 701 allows a lay witness to give opinion testimony if it is:

• Rationally based on the perception of the witness; and
• Helpful to understanding the testimony or determining a fact in issue.

Thus, a witness may say, “He looked drunk,” or “The car was going very fast,” provided those opinions stem from their personal observations. If the factual basis for the perception is weak, that affects credibility but not competency, assuming basic observation occurred.

Ability to Remember

While memory is essential for testimony, imperfections in memory generally affect credibility, not competency. A witness is competent even if they cannot recall every detail, if their recollection is hazy, or if their memory has faded over time.

Only in extreme cases—where the witness effectively remembers nothing about the relevant event—will lack of memory render them incompetent as to that subject.

Tools for dealing with memory problems include:

• Present recollection refreshed (FRE 612):
  If a witness has trouble remembering, their memory can be refreshed using almost any item (often a document, notes, or a photograph). The item is shown to the witness; if it jogs their memory, they then testify from their present recollection. The writing itself is usually not admitted as substantive evidence by the proponent.
• Past recollection recorded (FRE 803(5)):
  If refreshing fails and the witness still cannot remember, a record that the witness previously made or adopted when the matter was fresh may be read into evidence as a recorded recollection. The record must accurately reflect the witness’s knowledge at the time it was made. It is read to the jury; only the opposing party may introduce the record as an exhibit.

In both situations, the witness is still considered competent; the rules simply provide mechanisms to get reliable information before the fact-finder.

Worked Example 1.2
A witness saw a shooting three years ago and wrote a detailed statement that night. At trial, she testifies that she remembers seeing the shooter but cannot recall details such as distance, lighting, or whether the shooter wore glasses. After reviewing her prior statement, she still cannot independently remember those details. The proponent offers the statement under the recorded recollection exception. The opposing party objects that the witness is incompetent due to poor memory. How should the court rule?

Answer:
Overrule the objection. Imperfect memory affects credibility, not competency. The witness perceived the event and remembers at least some aspects. Because her current memory is insufficient, the prior statement may be read to the jury under FRE 803(5) if its foundational requirements are met.

Severe memory impairments: Severe dementia, amnesia, or brain injury can raise closer questions. A witness who cannot remember anything about the event may lack personal knowledge at the time of testimony and be incompetent as to that topic. But where the witness can recall even part of what occurred, the usual result under the Federal Rules is admission, with vigorous cross-examination.

Oath or Affirmation Requirement (FRE 603)

Before testifying, a witness must give an oath or affirmation to testify truthfully. This requirement emphasizes the witness's duty to relate events accurately and truthfully.

The exact wording is flexible. The key is that the form used is “calculated to awaken the witness’s conscience” and impress upon them the duty to tell the truth. Religious formulas are not required; secular affirmations are permitted and equally effective.

FRE 603 is where the witness’s understanding of truthfulness is tested. A witness who cannot comprehend the difference between truth and lies, or who does not understand that they must tell the truth in court, may be found incompetent.

Ability to Relate Accurately

The oath or affirmation requirement directly addresses the witness's ability and duty to relate their knowledge truthfully and accurately.

The ability to relate has two components:

1. Understanding the truth-telling obligation.
   The judge may ask simple questions—especially with children or persons with cognitive limitations—such as:

   • “Do you know what it means to tell the truth?”
   • “What happens if you tell a lie?”
     If the witness shows they understand that lying is wrong and promises to tell the truth, the oath requirement is satisfied.

2. Practical communication ability.
   A witness must be able to communicate their perceptions and memories in some understandable form. Problems here include:

   • Language barriers (requiring an interpreter).
   • Speech impediments.
   • Deafness or muteness.
   • Limited vocabulary (e.g., young children).

Under FRE 604, interpreters must be qualified and must take an oath to make a true translation. With a competent interpreter, a non-English-speaking witness is just as competent as an English speaker.

Communication difficulties rarely lead to a finding of incompetency, provided there is a workable way to get the witness’s testimony to the jury. Courts can use:

• Interpreters (including sign-language).
• Alternative questioning methods.
• Allowing the witness to point to diagrams or photographs.

Only if communication is so impaired that the fact-finder cannot meaningfully understand the testimony will the witness be deemed incompetent.

Worked Example 1.3
Plaintiff calls an adult witness who suffered a stroke and now has significant expressive aphasia. The witness understands questions and can answer “yes” or “no” but cannot form full sentences. Plaintiff proposes to use carefully framed yes/no questions and a speech therapist as an interpreter. The defense objects that the witness cannot "relate" events and is incompetent. How should the court rule?

Answer:
Overrule the objection. FRE 603 and 604 are satisfied if the witness understands the duty to tell the truth and can communicate in a way that the jury can understand, with the aid of an interpreter if necessary. Limited speech affects the detail and weight of the testimony, not basic competency.

Worked Example 1.4
Plaintiff calls an 8-year-old child to testify about a car accident he witnessed. Before the child testifies, the judge asks the child simple questions about the difference between telling the truth and telling a lie, and asks the child to promise to tell the truth. The child demonstrates understanding. The defendant objects, claiming the child is too young to be competent. Should the objection be sustained?

Answer:
No. Under the FRE, age alone is not a disqualifier. The judge properly inquired into the child's ability to understand the duty to testify truthfully (FRE 603). As long as the child also demonstrates personal knowledge (FRE 602) of the events, he is competent. His youthfulness may affect the weight the jury gives his testimony.

Competency vs. Credibility: A Frequent MBE Trap

Many MBE questions hinge on whether a problem is one of competency (admissibility) or credibility (weight). The general pattern:

• Competency/inadmissibility where:

  • The witness had no opportunity to perceive the event.
  • The witness has no present recollection of the matter at all and no usable recorded recollection.
  • The witness cannot understand the obligation to tell the truth.
  • Communication is so limited that the jury cannot make sense of the testimony.

• Credibility/weight where:

  • The witness had a poor vantage point, bad lighting, or was briefly distracted.
  • The witness was intoxicated at the time, but still perceived something.
  • The witness’s memory is partial or inconsistent.
  • The witness has biases, motives to lie, prior convictions, or mental health problems but can still understand and answer questions.

These credibility issues are explored through cross-examination and impeachment (e.g., showing bias, prior inconsistent statements, sensory impairments). They almost never justify excluding the witness altogether.

Exam Warning

Do not confuse issues of credibility with issues of competency under the FRE. While factors like poor eyesight, hearing impairment, memory lapses, or bias might significantly impact how believable a witness is (credibility), they generally do not make the witness legally incompetent to testify, provided the basic requirements of personal knowledge and understanding the oath are met. Incompetency is rare under the FRE.

Worked Example 1.5
During a bar fight case, a witness admits that at the time of the incident he had consumed several drinks and was “pretty drunk.” He testifies that he saw the defendant punch the victim. The defense moves to exclude his testimony, arguing his intoxication renders him incompetent. How should the court rule?

Answer:
Deny the motion. The witness’s intoxication goes to credibility, not competency, because he still perceived the event and can recount it. The jury evaluates whether to believe his testimony in light of his drinking.

Key Point Checklist

This article has covered the following key knowledge points:

• FRE 601 presumes every person is competent to be a witness unless another rule (or, in civil diversity cases, applicable state law) provides otherwise.
• Competency is built around four basic abilities: to observe, remember, relate, and understand the obligation of the oath or affirmation.
• FRE 602 requires that a lay witness have personal knowledge of the matter they testify about, meaning they must have perceived it with their senses (ability to observe and at least some ability to remember).
• Imperfect perception or memory typically affects credibility, not competency. Only extreme failures—no opportunity to observe or no recollection at all—defeat competency.
• FRE 612 and FRE 803(5) allow present recollection to be refreshed and past recollections to be read into evidence, addressing memory issues without making the witness incompetent.
• FRE 603 requires every witness to give an oath or affirmation to testify truthfully, demonstrating their understanding of the duty to relate events accurately.
• Communication difficulties and language barriers are addressed through interpreters under FRE 604; they usually impact the weight of testimony, not basic competency.
• Challenges to a witness's ability to observe, remember, or relate usually go to the weight of the testimony (credibility), not its admissibility based on competency.

Key Terms and Concepts

• Competency
• Personal Knowledge
• Oath or Affirmation
• Ability to Observe
• Ability to Remember
• Ability to Relate
• Interpreter
• Credibility