What Is Eyewitness Identification?

What Eyewitness Identification Generally Means

Eyewitness identification generally refers to the process by which a person who witnessed an event — such as a crime — identifies someone as an individual they saw in connection with that event. The identification might occur in a formal setting arranged by investigators, or it might arise in other ways, such as through a description a witness provides shortly after the event.

When a witness makes an identification, that identification can become a form of evidence in a legal proceeding. Courts and legal systems generally treat eyewitness identification as a category of evidence that can be considered alongside other evidence in a case, rather than as something that is automatically conclusive or automatically disregarded.

What counts as an identification, what procedures surround it, and how it is presented or weighed in court can vary considerably depending on the jurisdiction and the specific circumstances of a case.

Why Reliability Can Vary

Courts and researchers have long discussed the idea that human memory and perception are not perfectly accurate recording devices. A witness's recollection of an event, and of the people involved, can be affected by a range of factors — and those factors can influence how closely a witness's identification reflects what actually occurred.

Some of the factors that have been discussed in this context include:

• Stress and emotional state — High levels of stress or fear at the time of an event can affect how a person perceives and later recalls what they saw.
• Lighting and viewing conditions — The amount of light available, whether an event happened at night or indoors, and similar physical conditions can affect what a witness was able to observe clearly.
• Distance and duration of observation — How far away a witness was from the events they observed, and how briefly or at length they had an opportunity to observe, can play a role in what details they retain.
• Passage of time — Memory can change over time. The longer the gap between the event and the identification procedure, the more opportunity there may be for a witness's recollection to shift or fade.
• How the identification procedure is conducted— The way an identification procedure is administered can itself influence a witness's response, which is one reason that identification procedures have been a subject of ongoing discussion and development in legal and research communities.
• Other individual and situational factors— Various additional elements, including a witness's familiarity with the person they are identifying and the overall circumstances of the event, can also come into play.

It is worth noting that these factors do not automatically mean any given identification is unreliable — rather, they represent considerations that can inform how reliability is examined in a particular case. Reliability is generally understood to exist on a spectrum and to depend on the full set of circumstances surrounding each identification.

It Is Generally Examined and Tested, Not Simply Accepted

One important concept in how legal systems approach eyewitness identification is that reliability is generally treated as something that can be examined and questioned, rather than something that must be taken at face value. This means that when an identification is offered as evidence, there are often avenues through which its reliability may be explored.

That examination might happen in various ways. In some proceedings, evidence about the conditions under which an identification was made — lighting, distance, stress, the procedures used — can be presented to help the fact-finder understand how much weight to give the identification. Expert knowledge about human memory and perception may also, in some jurisdictions and circumstances, be introduced to provide context.

A related concept is the broader practice of testing the accuracy and credibility of witness testimony generally. Information about how witnesses can be questioned and their accounts examined is discussed in the concept of witness impeachment. It can also be useful to understand what distinguishes a lay witness — an ordinary observer — from other kinds of witnesses, which is covered in the concept of what a lay witness is.

Whether and how reliability can be examined in any particular proceeding depends on the applicable rules and the specific facts at issue. The general principle, however, is that an eyewitness identification is subject to scrutiny rather than insulated from it.

How It Relates to Identification Procedures

Eyewitness identification as a concept is closely connected to the formal procedures through which identifications are often made. Investigators and law enforcement agencies sometimes use structured procedures to present people or images to a witness and ask whether the witness can identify anyone in connection with an event.

One widely known type of identification procedure is a lineup — an arrangement in which a witness is presented with a group of individuals (or photographs of individuals) and asked to indicate whether they recognize anyone. The concept of a lineup as an identification procedure, including the general ways such procedures are typically structured, is explored in more detail in the related concept of what a lineup is.

The connection between eyewitness identification and identification procedures is significant because how a procedure is conducted can affect the resulting identification. Questions about whether a procedure was fair, whether it was administered in a way that could have influenced the witness, and whether proper guidelines were followed are generally considered relevant when examining the reliability of an identification that emerged from such a procedure.

How It Fits Into the Bigger Picture of Proof

Eyewitness identification is generally understood as one form of evidence — one piece of information that a fact-finder might weigh when reaching a conclusion about what happened. It does not exist in isolation from other evidence, and it does not carry a fixed value independent of the other circumstances of a case.

In legal proceedings, a fact-finder — whether a judge or a jury — considers the full picture of the evidence presented. An eyewitness identification might be consistent with, or in tension with, other evidence such as physical evidence, documentary evidence, or the accounts of other witnesses. The weight given to any identification can depend on how it interacts with the rest of what is known about a case.

This connects to foundational concepts in the law of proof. The standard of reasonable doubt — the level of certainty generally required in criminal proceedings — is relevant to how all evidence, including eyewitness identification, is ultimately evaluated. Similarly, understanding what elements of a crime must be established can provide context for what role identification evidence plays in connecting a specific person to those elements.

Eyewitness identification is neither inherently sufficient on its own to establish what happened nor inherently insufficient — it is one kind of evidence whose weight depends on the full circumstances of the case and the quality and circumstances of the identification itself.

Questions to Explore About Eyewitness Identification

If eyewitness identification is relevant to a case or situation, some people find it useful to ask broad informational questions to better understand the concept and its context. The following are general questions that can help frame an inquiry:

1. Under what conditions did the identification take place — for example, what was the lighting, what was the distance between the witness and the person identified, and how much time did the witness have to observe?
2. What kind of identification procedure, if any, was used, and what information is generally available about how that type of procedure is typically administered?
3. How much time passed between the original event and when the identification was made, and were there any intervening events that might have affected the witness's recollection?
4. What other evidence exists in the case, and how does the eyewitness identification fit alongside or in tension with that other evidence?
5. In the relevant jurisdiction, what general principles or frameworks apply to how eyewitness identification evidence is presented, examined, and weighed in legal proceedings?