New study: Detecting deception via Cognitive Interviewing
New study: Detecting deception via Cognitive Interviewing
The Cognitive Interviewing process that can enhance the memories of witnesses and involved officers during use-of-force investigations has now been modified to make it a useful tool for also detecting possible deception when questioning suspects about crimes.
The modified protocol includes 2 unexpected requests that seem especially effective in exposing untruthfulness: 1) Asking the suspect to sketch 1 or more drawings to illustrate his story and 2) asking him to repeat his account in reverse order of occurrence, beginning with the end of the story and working backward in time.
“Unexpected requests can trip up a liar,” explains Dr. Edward Geiselman, a Force Science certification instructor and a psychology professor at UCLA. “A deceptive subject’s cognitive resources already are being strained to the limit to create his story and maintain it consistently. Increasing that load even more with these demanding and surprising tasks can provoke potential signs of deception, if you know what to look for.”
It’s been some 3 decades since Geiselman and Dr. Ron Fisher of Florida International University first introduced Cognitive Interviewing to law enforcement. Since then, that approach, with its emphasis on rapport-building and open-ended narration and memory prompting, has been subjected to more than 100 scientific laboratory tests, as well as innumerable workaday field applications.
Results have been remarkably consistent: Typically, CI elicits between 25% and 40% more correct and relevant information than conventional, often confrontational police Q & A, Geiselman says. CI has been adopted by the FBI, the Dept. of Homeland Security, and the Defense Intelligence Agency, as well as by police departments in the U.S., Canada, and abroad.
Now, addressing a desire by investigators to enhance their ability to pinpoint lies, Geiselman has introduced 2 additional elements to the original 6-stage CI process. He calls this extended version the Cognitive Interview for Suspects (CIS), and describes the application and assessment of it in an article accepted by the American Journal of Forensic Psychology for publication later this year.
TRUTHS & LIES. During sessions in his research lab, Geiselman writes, he matched up 2 groups of participants: 20 male and female college students of various ethnicities, averaging about 20 years of age, who served as interview subjects, and 6 undergraduate research assistants who were trained to conduct the CIS procedure.
Each interviewee was to relate 2 personal “life events”: 1 that had actually occurred within the last 3 months and another that they made up but had “never really happened, even in part.” Their assignment was to tell about both “in such a manner that the interviewer would believe it actually happened” and to “maintain this ruse to the very end.”
The interviewers, without prior knowledge as to truth or fiction, were to elicit accounts of the events by following the CIS format and to judge after each stage of the process whether the interviewee at hand was lying or giving honest information. The interviewers were cautioned not to approach the interaction with any preconceived bias regarding truthfulness.
STEP-BY-STEP PROCESS. The same procedure was followed for each interview.
1. Introduction/rapport. The interviewer introduced him/herself and spent a few minutes chatting casually and non-judgmentally with the “suspect” on neutral topics and shared interests about which the subject had no reason to lie. This served to put the subject at ease and to build rapport, and also allowed the interviewer to “observe the subject’s general demeanor as a baseline.”
2. Narrative. The suspect was instructed to tell about the event “in as much detail as possible and to take as much time as needed to concentrate.” The interviewer did not challenge any aspect of the story and, indeed, spoke only to use “extenders” and other prompts (“Really…tell me more about that”) “to keep the narrative going as long as possible.”
3. Drawing/sketch. Unexpected by the suspect, he/she was asked to draw an illustration or diagram related to the event “to clarify the narrative for greater understanding by the interviewer, as well as to give the subject another opportunity to recall additional information.” Specifically, the subject was asked to sketch the general layout of the area where the incident was said to have occurred and then to trace the path of events as they unfolded from beginning to end
4. Follow-up. For further clarification, the interviewer asked open-ended questions “presented as information-gathering rather than as confrontational to maintain the momentum toward generating more information from the suspect.” Delaying confrontation while priming the suspect for maximum commentary, Geiselman explains, allowed for “greater opportunity to observe inconsistent statements as well as any verbal, vocal, and behavioral changes from the baseline.”
5. Reverse-order technique. When all the scenes from the narrative were exhausted with follow-up questions, the interviewer then asked the subject to describe the event again, this time step-by-step in a backward sequence, a technique that tends to more successfully jog a truthful subject’s memory for additional details than repeating the story from start to finish.
6. Challenge. At this point, using the same soft-spoken, respectful manner, the interviewer confronted the subject about “inconsistencies, incriminating statements, and/or external incriminating evidence,” none of which had been mentioned before this point. The interviewer could even accuse the subject of “lying to me this entire time.”
(Two components of the traditional CI were eliminated during this experiment: the Review phase, when the interviewer offers a summary of the subject’s story so the interviewee can correct inaccuracies or recall additional facts, and the Closure, when the interviewer expresses gratitude for truthful responses or disappointment about a subject’s suspected attempts to deceive.)
DECEPTION DETECTION. When Geiselman analyzed the interviewers’ phase-by-phase assessments of whether they were hearing true or fabricated stories, he found that the interviewers’ ability to distinguish deception improved “systematically as the interviews progressed.”
His assistants’ accuracy in picking out the false stories wasn’t significantly better than chance after the rapport-building and narrative stages. This, despite the fact that “narratives offered by the interview subjects when they were being truthful were significantly longer…than when they were being deceptive,” Geiselman notes.
“The drawing task improved the detection of deception by revealing some time-consuming difficulties…on the part of deceptive subjects,” he writes. “[T]he interviewers reported unanimously that the subjects whom they [accurately] thought were being deceptive failed to include significant elements from their narratives in their drawings, whereas truthful subjects tended to add a few new details in their drawings.
“Deceptive subjects frequently needed to start over with their drawings due to inconsistencies, and they tended to change and/or correct elements of their stories. Overall…deceptive subjects required more time to complete their illustrations, even though it was the truthful subjects who tended to add some new details during this stage.”
The interviewers also scored “modest increases in detection accuracy” after the follow-up questioning. Truthful responses took “significantly longer” this time because of the more detailed answers truth-tellers provided.
After the second surprise gambit–asking that the story be told in reverse–detection of deception “improved substantially,” Geiselman says. Deceptive subjects “tended to require prompts to keep them from making significant leaps backward (‘What happened right before that?’) and reverting to forward-order recall. Research shows that deceptive persons have unusual difficulty telling fabricated stories backwards.”
By the time the process reached the challenge stage, “most interviewers already had decided that most of the deceptive subjects were, in fact, deceptive,” Geiselman reports.
In debriefings, the interviewers agreed on certain key differences between subjects they believed were truthful and those they suspected of lying. Geiselman itemizes:
• “When asked to clarify unresolved inconsistencies in their stories, truthful subjects most often offered explanations that involved miscommunication (‘I wasn’t clear before, let me explain…’), whereas deceptive subjects most often offered explanations that involved claims of faulty memory (‘I was mistaken before; it was this way…’).”
• “When asked if the subjects wanted to add anything, deceptive subjects tended to either respond NO quickly or they simply repeated elements from their narratives. In contrast, truthful subjects tended to either make elaborations or at least hesitate to search memory before saying NO.”
• “When challenged directly…about having lied, deceptive subjects most often appeared unhappy and uncomfortable, then offered weak denials or deflected the direct challenge… In contrast, the truthful subjects were more likely to give a firm denial about not having lied” and often offered additional information in support of their position.
Finally, Geiselman points out, the interviewers unanimously agreed that each of 3 major deception indicators identified in previous research were “more apparent” in subjects they accurately thought were lying, especially during the Drawing, Reverse-order, and Challenge stages of the CIS. Namely:
• There was “something unnatural” about their stories–”few details, ends abruptly, contradictions, lacking chronology, vague or illogical story line, and awkward use of terms.”
• These subjects exhibited “exaggerated behavior”–smiling inappropriately, shrugging, grooming, rationalizing.
• These subjects displayed “unusual eye movements or contact,” such as “blinking, squinting, exaggerated movements, and looking down or around the room.”
CAUTION. While Geiselman regards the expanded CIS template as a “promising” tool for attentive and sensitive investigators, he cautions that individual indicators of deception should be considered only as “red flags” or “hot spots” in an interview.
Distinguishing lies from truth “is not an easy task,” he writes. “Detection of any one indicator…should not be taken as sufficient evidence to conclude that the subject is being deceptive. Instead, judgments…must be based on the overall pattern of performance through the entire CIS protocol.”
Further, he acknowledges important limitations in his study. For example, the “suspects” were “college students operating in a low-stakes environment. Skilled liars under high-stakes conditions would conceivably be more difficult to detect, and truthful persons under stress and/or sleep deprivation would conceivably exhibit some characteristics of liars.”
However, he is encouraged by the fact that his young research assistants, who received only 6 hours’ training in the CIS techniques and had no external information about the subjects’ stories in advance and no investigative experience, were able to “learn and apply [the protocol] with considerable accuracy.”
In real-world applications of cognitive techniques, some investigators have reported that “suspects with some frequency get so caught up in the memory-jogging elements that they wind up stating things that only the perpetrator could have known,” Geiselman told Force Science News. During one Cognitive Interview, a suspect recalled seeing a murder victim “still twitching”–after claiming in prior conventional interviews that he happened upon the scene long after the shooting stopped.
Heartened by the possibilities, Geiselman concludes that more research, including a direct comparison with “confrontation interrogation techniques,” is “certainly warranted.”
Dr. Geiselman’s official report on “The Cognitive Interview for Suspects” will appear in Vol. 30, Issue 3 of the American Journal of Forensic Psychology, due out in July. Meanwhile, Geiselman, who conducts training on Cognitive Interviewing and deception detection, can be reached at: firstname.lastname@example.org