In psychology, a person's motivation generally relates to the strength of their desire to accomplish a specific goal, which is also referred to as their drive. On the other hand, the concept of motivation in criminal investigation refers to the need a suspect fulfilled by committing a criminal act such as financial gain, power, esteem, etc. This difference is not incompatible, for a person's clarity in defining a specific goal and the drive to accomplish that goal both encompass the construct of motivation. If a suspect lacks either a specific goal or the drive to accomplish that goal, inferences of truth or deception are often misleading.

A good example illustrating the relationship between goal orientation and the drive to accomplish a goal is the research that has been published investigating detection of deception. Laboratory studies create an artificial scenario where subjects are assigned the role of either committing a mock crime or not committing it. These "liars" or "truth-tellers" may then be administered a polygraph examination or face to face interview to collect data which is subsequently analyzed for indications of truth or deception. With this methodology, the typical result is that neither procedure achieves accuracies much above chance levels. However, when using similar data derived from actual criminal suspects (field studies) the same analysis consistently reveals accuracies far above chance levels.

The difference between these two populations is the level of motivation. "Truthful" laboratory subjects often do not form a clear goal of needing to be reported as telling the truth. While the deceptive laboratory subjects may have a clearly defined goal of avoiding being detected in a lie, they have very little drive to accomplish that goal. Consequently, both "truthful" and "deceptive" laboratory subjects produce similar polygraph charts or behavior during an interview. On the other hand, because a criminal suspect's livelihood, reputation and freedom are at stake, both innocent and guilty suspects form clear goals and a strong drive to accomplish the goal. It is important to appreciate that innocent and guilty suspects form different goals during an interview or polygraph examination. The innocent suspect's goal is to be exonerated or reported as telling the truth. The deceptive suspect's goal is to not have his guilt identified. This difference in goal orientation forms the basis for all inferential lie detection procedures.

With this background, it must be remembered that not all criminal suspects operate from high levels of motivation. A common exception is the innocent person who is essentially told, at the outset of the interview, "I don't believe you had anything to do with this crime." Under this circumstance the person has no need to establish a goal of being exonerated. The result may be unresponsive polygraph charts and possibly misleading behavior symptoms. Examples of these misleading behavior symptoms include failing to name a particular suspect, vouching for everyone, failure to speculate as to possible motivations by the guilty and offering a noncommittal punishment toward the guilty person. In essence, the unmotivated innocent subject lacks a number of underlying attitudes seen from an innocent suspect who is highly motivated to be exonerated.

To maintain high levels of motivation during an interview, an investigator should avoid downplaying the suspect's possible involvement in a crime. During a formal interview our introductory statement to all suspects is, "If you were involved in (crime) our investigation will clearly indicate that. If you had nothing to do with this it will show that as well." Our experience has shown that, especially suspects who are innocent of involvement in a criminal offense, need to be stimulated to form a clear goal of needing to be exonerated to produce behavior indicative of that fact.

In the opposite situation, the guilty suspect may be so overwhelmed with evidence against him that he does not form a strong inner drive to escape being detected in his crime. In essence, this suspect experiences a feeling of helplessness going into a polygraph examination or interview. During a polygraph examination this suspect may not exhibit significant arousal when he denies involvement in the crime - he is convinced that the polygraph will detect his lie and, therefore, is not motivated to avoid detection of deception. During an interview his nonverbal behavior may appear withdrawn and distant but the verbal content of his responses to behavior provoking questions may be more typical of the innocent. For example, the suspect may openly acknowledge that a crime was committed and that he had the best opportunity and motive to commit it. He may even offer a reasonably harsh punishment for the guilty person and deny that the guilty person should be given a second chance. This is exactly the behavior displayed by a guilty suspect who, prior to our interview, had already told her husband about her commission of the crime. Acting on factual information we interrogated the suspect and she readily confessed. During a post-confession interview she explained that her husband had already forgiven her and she had accepted the fact that she would be punished for what she did. When asked why she did not just come forward and admit her guilt she stated that husband advised her to lie.

With respect to the guilty suspect who lacks motivation because he has given up, we generally suggest that an investigator withhold incriminating evidence from a suspect until the interview or even interrogation. By doing so, not only is the suspect more likely to agree to be interviewed, but his level of motivation will remain high. During an interview the investigator wants the guilty suspect to believe that he can escape detection by suggesting that no crime was committed, opening up the investigation by naming unrealistic suspects, stating that the guilty person deserves leniency, etc.

The preceding comments all relate to the subject's internal motivation during non-accusatory procedures (polygraph examination and interviews). What happens when the external level of motivation is significantly increased through an accusatory interaction, such as during an interrogation? There are some behaviors, both truthful and deceptive, which become more obvious during an interrogation. For example, a truthful suspect's denials become much more forceful and emphatic during an interrogation. On the other hand, the accusatory nature of interrogation may amplify intrinsic factors affecting a person's behavior (personality, culture, intelligence, etc.) which may decrease the reliability of some behavioral observations. Finally, there are a number of specific behavior symptoms which take on quite different interpretations whether they occur during a non-accusatory interview or an accusatory interrogation.

One of these is the use of non-contracted denials, e.g., "I did not start that fire." During an interview, non-contracted denials are more often heard from deceptive than truthful suspects. However, during an interrogation, non-contracted denials, especially when delivered in a staccato fashion, are associated with truthfulness. Similarly, a bolstered phrases such as, "I swear, I don't know anything about that fire!" is indicative of deception during a non-accusatory interview. During an interrogation an innocent suspect, out of frustration or anger, may make the same statement. On the nonverbal level, staring or a forward-leaning posture throughout an interview is often a sign of deception, where the guilty suspect is forcing his presence on the investigator. However, during an interrogation these behaviors may be a good sign of sincere anger and shock, which is more indicative of truthfulness.

These are but a few examples of behaviors which are affected by the nature of the interaction with the investigator. They indicate why, when we do consultations to evaluate a suspect's behavior, we always ask whether or not the suspect has been accused of involvement in the offense or has been previously interrogated on it. Becoming confrontational with a suspect introduces a new variable to consider when evaluating behavior. If the accusation is clear and direct such as, "Tom, there is no doubt that you are the person who started that fire!" we can confidently assess the suspect's behavior. Where problems arise is when the investigator shifts from non-accusatory to accusatory questioning and then returns to non-accusatory questions. A lesson we emphasize during our training seminars is worth repeating: If you are going to interview - interview. If you are going to interrogate - interrogate.

In summary, an investigator must be aware of the subject's level of internal motivation to form clear goals and the drive to accomplish that goal. In this regard, the investigator should approach each interview in an impartial manner and certainly not downplay the possibility that the person being interviewed is considered as someone who may have involvement in the offense, or be motivated to withhold information. Second, the investigator should not overwhelm a suspect with incriminating evidence prior to the interview. To do so not only decreases the likelihood that the suspect will voluntarily agree to be interviewed, but may create a sense of helplessness which can distort goal orientation and cause misleading behavior or polygraph charts. Finally, the investigator must appreciate the influence that the nature of the interaction with a suspect (non-accusatory, accusatory) has on that person's behavior.