Week 5 Lecture

Interviews and Eyewitness Identifications

Witness testimony is essential to the investigative process. The information provided by a witness can describe the perpetrator and his/her actions. A witness may even be able to positively identify a perpetrator. Though eyewitness testimony is persuasive, it is often unreliable. Therefore, the methods of identification used by the police must incorporate an understanding of the memory process and the factors that can influence it.

Interviews Defined

An investigative interview is any questioning that is intended to produce information regarding a particular crime or suspect. The goal is to develop information to move the investigation forward.

Types of Witnesses

A primary witness is a witness who has direct knowledge of a crime or a suspect.

  • Some primary witnesses are eyewitnesses. Eyewitnesses saw the crime occur or saw related events that occurred just before or after the crime.

A secondary witness is a witness who has information about related events before or after the crime.

Types of Information Obtained from Witnesses

  • Actions of the perpetrator can establish an individual’s MO. A particularly useful piece of evidence for linking crimes and creating behavioral evidence.
  • Descriptions of the perpetrator provide a basis for developing a composite sketch or picture of the perpetrator.
  • Identification (or name) of the perpetrator is the most useful type of information.

Methods of Eyewitness Identification

An eyewitness may identify a perpetrator through one or more methods.

  • The witness provides information for a composite picture of the perpetrator.
  • The witness views mug shot books.
  • The witness views the suspect through a show-up situation.
  • The witness views a photo line-up or photo array.
  • The witness views the suspect and others in a physical line-up.

Show-up Identifications

A show-up identification involves bringing the suspect back to the scene or to the location of the witness for identification. This is usually performed under circumstances where there was a quick apprehension.

  • A witness’ memory is fresh in this situation since the incident has just occurred and there is less pressure since the police do not know much at this point. Though witnesses are more cautious to make an identification in this situation, show-ups are suggestive and misidentification is likely.

Photo Line-ups

  • Photo line-ups are useful when investigators believe they know the perpetrator of a particular crime.
  • Investigators show a witness a group of five or six images for identification. One of these images is the suspect and the others fit the description but are not believed to be involved in the crime.

Live Line-Ups

  • Live, or physical, line-ups involve witnesses viewing the suspect and others in a controlled setting for identification. These individuals should match the initial description provided by the witness and there should be nothing suggestive regarding who the suspect is.

Value of Eyewitness Identifications in Establishing Proof

  • Eyewitness identification is one of the least reliable types of information, yet it is extremely persuasive at establishing proof.
  • Eyewitness error is the most common factor in wrongful convictions, according to the Innocence Project. Many of these eyewitnesses also express high confidence in their judgment.

The Memory Process and the Identification Task

The memory process involves three phases: encoding, storage, and retrieval.

  • Encoding (or acquisition) is when the event is perceived.
  • Storage (or retention) involves the “filing” of the information.
  • Retrieval occurs when the mental record or the “file” of the event is activated or recollected.

A relative-judgment process is when the eyewitness chooses the individual most representative of the description when compared to the others. However, if the suspect is not there, this is a problem.

Factors that Influence the Accuracy of Eyewitness Evidence

During the acquisition stage, the circumstances and nature of the event, as well as the characteristics of the witness, will influence the information absorbed by the witness.

Circumstances that may affect the acquisition of information:

  • Lighting conditions, distance, and obstructed views can have a significant impact.
  • The duration of the event is also important.
  • If the event is viewed as insignificant, it can be harder to recall.
  • Simple disguises, like a baseball cap, can impair identification.

Characteristics of witnesses that may affect the acquisition of information:

  • High levels of fear and stress can substantially reduce the accuracy of information.
  • Physical conditions must also be considered.
  • A witness’ expectations can also affect the accuracy of information.
  • When a witness has knowledge about a particular object, they may be able to provide more accurate information.
  • Age has been shown to be important (children and elderly provide less accurate information).
  • Females are more reliable but men are more confident.

During the storage stage, several factors can distort the accuracy of information.

  • Misleading or inaccurate information obtained at or near the time of the event. A way to prevent this is to separate all witnesses as soon as possible.
  • Also, the more time that passes, the less accurate the information will be.

During the retrieval stage, there are other factors that can influence the accuracy of information.

  • The manner in which the retrieval occurs, such as the way questions are worded, can be important.


Hypnosis is an altered state of consciousness characterized by an increased responsiveness to suggestion. It has been used to enhance memory recall of a witness to a criminal event.

There are three approaches to hypnosis for criminal investigations:

  • A free recall is when a witness is asked to create an unstructured account of what occurred.
  • A structured recall is when the witness is asked specific questions about their observations.
  • Recognition is when a witness is asked to recognize certain aspects of the event.
  • Because individuals under hypnosis are more susceptible to suggestions, this process often results in fabrications or false information.
  • The general rule in its admission in court is that previously hypnotized witness may testify their recollections prior to the hypnosis. All testimony recorded during and after hypnosis may not be admitted into court.

Cognitive Interviewing

Cognitive Interviewing encourages the witness to reinstate the context of the observed event and search through their memory for details systematically.

Techniques for this approach are as follows:

  • The witness must first recreate the context of the original event, both the content and the physical and psychological characteristics of the environment as well.
  • The witness then is encouraged to concentrate and focus through closing her eyes and breathing deeply.
  • The witness should then be encouraged to search her memory thoroughly.
  • Retrieval of the event should be done in multiple ways such as reversing the order of events, describing “frames” of the event, or through another person’s perspective of the scene.

Other techniques should also be used to enhance recollection of specific pieces of information.

There are significant benefits when using cognitive interviewing as opposed to traditional police interviewing. It is has shown to be an effective tool at memory recall.

The following are problems associated with traditional police interviewing:

  • Interviewers frequently interrupt witnesses.
  • Interviewers ask too many short-answer, close-ended questions.
  • Inappropriate, arbitrary, or rigid sequencing of questions.
  • Interviewers sometimes use negative phrasing.
  • Interviewers sometimes use non-neutral questions.
  • Interviewers sometimes use inappropriate or too formal language.
  • Interviewers ask questions too rapidly.
  • Interviewers sometimes make judgmental or insensitive comments to the witness.
  • Interviewers would sometimes fail to follow-up on potential leads provided by the witness.

There are basic rules associated with effective police interviews as a result of the success of cognitive interviewing.

  • Witnesses should be separated and interviewed one at a time.
  • Interviews should be conducted away from distractions.
  • Interviews should be conducted as soon as possible after the event.
  • It is important that investigators develop a rapport with witnesses.

Interrogations and Confessions

During the course of an investigation, suspects are identified and an interrogation is necessary. An interrogation is the accusatory questioning of a person believed to be the perpetrator of a crime with the intentions of obtaining a confession from this person. The interrogation of a suspect is a game of persuasion, where deception is used on both sides. Investigators carefully consider certain themes or tactics that are appropriate to persuade a particular individual to confess. It is important to note, however, that false confessions can be elicited through these tactics. Therefore, caution must be taken in the steps of interrogation.

Interrogation Defined

  • An interrogation is all questioning and other actions made by an investigator that is done with the intention of eliciting information from a suspect for criminal prosecution. It is an intimidating process and is typically done when an individual is in custody.
  • The ultimate goal of an interrogation is to obtain a confession. Though the individual being interrogated is not always the perpetrator, so it is important that the investigator does not elicit a false confession.
  • Deception is a common response to interrogation. Though it is important to note that deception should not be necessarily equated with guilt, for individuals may deceive for many reasons.

The Psychology of Persuasion

Interrogation is basically the task of persuading a suspect to confess despite the fact that a confession may lead to a conviction and prison.

Why do people confess then?

  • Suspects may confess to relieve a guilty conscience.
  • Suspects may confess because of persuasive police actions.
  • Suspects may confess because the suspect believes there is no point in denying the crime due to the perceived evidence against him/her.

The Ingredients of a Successful Interrogation

In order for an interrogation to occur, the suspect must first waive their Miranda rights and be willing to answer questions.

Many studies however, find that most suspects waive their Miranda rights and continue to be questioned.

Of the suspects that waive their Miranda rights, a majority either confess or make incriminating statements.

What are the ingredients necessary to produce a successful interrogation?

  • A plan prior to the interrogation is necessary to determine the information that is known and needs to be known from the suspect. If there is more than one investigator, the investigators’ roles need to be determined prior to the interrogation.
  • Adequate time is needed in an interrogation in order for it to be successful.
  • Control of the conversation and setting by the investigator is fundamental to a successful interrogation.
  • Investigators involved in the interrogation must have a good understanding of the facts of a case to ask the right questions and to understand when an answer is conflicting with other facts of the case.
  • Interrogators should be familiar with the suspect’s background.
  • Investigators should build rapport with the suspect.
  • Investigators should be familiar with and comfortable using a variety of persuasive themes, approaches, and tactics.

Steps in the Interrogation of Suspects

The following are steps to be followed in conducting interrogations.

  1. The first step is to confront the suspect directly with a statement that he or she committed the crime and then wait for a reaction.
  2. The suspect should be classified as either an emotional or non-emotional offender to determine the most effective themes to be used for that suspect.

An emotional offender is likely to experience guilt and should be approached in a unique way. The following themes are most effective with emotional offenders.

  • Investigators should sympathize with the suspect.
  • Investigators should minimize the seriousness of the offense.
  • Investigators should suggest to the suspect a more acceptable motivation for the offense.
  • Investigators should condemn others.
  • Investigators should appeal to the suspect’s pride through flattery.
  • Investigators should acknowledge that the accuser might have exaggerated the nature or seriousness of the crime.
  • Investigators should highlight the grave consequences of continued criminal behavior.

A non-emotional offender does not experience a troubled conscience and does not feel the need to answer questions by the police. The following themes are most effective with non-emotional offenders.

  • Investigators should attempt to obtain an admission about some incidental aspects of the crime through the use of false evidence.
  • Investigators should point out the futility of denials.
  • Investigators should play one offender against another, if the crime involved multiple parties.

  1. Denials beyond the initial one should be cut off.
  2. Suspects who move from denials to objections are likely moving towards a confession. Objections often provide useful information for the development of themes.
  3. It must be continually clear to the suspect that the interrogator is interested in getting the truth and will not give up by maintaining eye contact and a close proximity to the suspect.
  4. Theme development should continue, furthering the idea that confessing is the best course of action at this point.
  5. The next step is to present an alternative question to the suspect to get the suspect to make a statement. Usually a question that elicits a one-word confession (yes or no) is offered.
  6. The suspect then is to orally relate the details of his or her involvement in the crime.
  7. The last step is to turn the oral confession into a written one in the form of a narrative.

The Issue of False Confessions

A false confession is where an innocent individual confesses to a crime, or overstates their involvement in the crime.

Why would someone confess to a crime that they did not commit?
  • Compliant false confessions are to escape the punishing experience by the stressors present in interrogations.
  • Persuaded false confessions are when investigators make an individual believe that it is more likely than not that he or she committed the offense despite having no memory of doing so.
  • Voluntary false confessions are when an individual comes forward to the police and confesses to a crime due to a desire for fame, guilt for another crime, mental illness, or to protect the person who actually did it.

Investigative Tools in Recognizing Deception

The ability to detect deception is important when obtaining information from people. The most commonly used methods can be classified as mechanical or non-mechanical. The basic theory behind these methods is that under stressful situations, like an interrogation, suspects will try to repress fight or flight responses through physiological changes.

  • Non-mechanical methods of detecting deception include verbal and nonverbal practices.
  • It is important to consider various factors when evaluating the meaning of these behaviors.
  • No single behavior is always indicative of deception.
  • Individual differences need to be considered.
  • Gender and ethnic/cultural differences also need to be considered.
  • The situation and environment need to be considered as well.
  • Behavioral clusters may be meaningful even though single behaviors may not be.
  • The timing of verbal and nonverbal cues needs to be considered.

Kinesics relates to the study of body movement and posture to convey meaning. Many deceptive people will engage in self-protective type behaviors to cope with the stress.

  • Emblems are gestures that convey direct meaning.
  • Illustrators are hand and arm displays that illustrate what is being said.
  • Truthful emblems and illustrators will be congruent with what is said while deceptive ones are incongruent.

What are the most common deceptive nonverbal behaviors?

  • Facial expressions like an individual’s eyes, mouth, and nose are good indicators of deception.
  • Body positioning and posture can be indicative of deception when one performs a protective or defensive action.
  • Gestures, like manipulators or “created jobs”, that distract the hands, may be revealing of attempts to deceive.

The “poor man’s polygraph” consists of four questions to determine whether a person is answering truthfully.

  • Typically, a deceptive person’s answer to “Why should I believe you?” is “I don’t know”.
  • Typically, a deceptive person’s answer to “I know you are lying” does not make reference to “the truth.”
  • Typically, a deceptive person’s answer to “Do you really want to get away with this?” will be yes or no.
  • Typically, a deceptive person’s answer to a critical yes or no question will begin with “well.”

Mechanical means of detecting deception include a polygraph and a computer voice stress analyzer. The polygraph is a machine that records the physiological responses (perspiration, blood pressure, and galvanic skin response) to psychological phenomena like stress of deception.

  • The Relevant-Irrelevant Test (RIT) asks a serious of relevant and irrelevant questions and is supposed to determine deception but is subject to a lot of error.
  • The Concealed-Information Test (CIT) involves multiple-choice questions concerning the “guilty knowledge” of the suspect.
  • The Control Question Technique (CQT) is the most common technique that asks both control questions and crime-relevant questions. The control questions threaten the innocent and the relevant questions threaten the guilty.

Polygraph tests can be highly accurate under appropriate circumstances but are likely to be abused. Accuracy rates average at around 60-75%.

  • Though not always accurate, polygraph tests are a useful threat to obtain a confession.
  • Factors that affect the outcome of polygraph results are personality characteristics and disorders of the examined individual, drugs used by the examined individual, and the experience of the examiner.
  • Physical and mental countermeasures can “beat” the polygraph.
  • Polygraph results are infrequently admitted into court.

Another mechanical means of detecting deception is the Computer Voice Stress Analyzer (CVSA). The CVSA is a machine that is supposed to detect stress in one’s voice.

  • In short, the CVSA has about zero validity but can still be useful in eliciting confessions from suspects.