Clusters of nonverbal behavior differentiate truths and lies about future malicious intent in checkpoint screening interviews

Abstract

Recent research has shown that nonverbal behavior (NVB) assessed across multiple channels can differentiate truthtellers from liars. No study, however, has examined whether or not multiple NVBs can differentiate truths from lies about intent regarding future malicious behavior, or across multiple cultural/ethnic groups. We address this gap by examining truths and lies about intent to commit a malicious act in the future in brief, checkpoint-type security screening interviews. Data from four NVB channels producing twenty-one observable NVBs were coded and analyzed using different analytic strategies. Clusters of NVB were found to differentiate truthtellers from liars at statistically significant levels, and substantially beyond the ability of human observers. The findings showed that clusters of NVB can differentiate truthtellers from liars even in brief, checkpoint-type interviews.

Keywords:

• nonverbal behavior
• veracity
• deception
• intent
• facial expressions
• gestures
• voice
• body movements
• shrugs

Acknowledgements

The data utilized in this study are available upon reasonable request to the authors for a period of five years after publication, as per the American Psychological Association (APA) guidelines. Statements of fact, opinion and analysis in this study are those of the authors and do not reflect the official policy or position of the Transportation Security Administration (TSA) or the US Government.

Ethical standards

Declaration of conflicts of interests

Both authors are employees of Humintell, a for-profit company that conducts applied research and training on the topics covered in this paper.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the University at Buffalo, State University of New York Social and Behavioral Sciences Institutional Review Board and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in this study.

Notes

1 Their analyses also showed that within a cluster of NVBs, some cues were relatively more important than others and neither motivation nor strong emotion were moderators of the effects. Levine (2018) also commented in his review that arguments about the importance of stakes invoked circular reasoning.

2 Burgoon et al. (2009) was labeled as an intent study but none of the test beds used in the paper was actually about intent regarding future malfeasance; rather, multiple test beds from experiments about current or past events were used to make a case for the use of indicators for future intent.

3 Considerably more detail than is reported herein about sampling, recruitment, cultural differences among the ethnic groups, interviewers and questions, stakes, procedures and specific instructions can be found in Matsumoto and Hwang (2015) and Matsumoto et al. (2015).

4 Thus, these samples consisted of both immigrants to the U.S., and Chinese-, HIspanic-, or Middle Eastern Americans..

5 The criteria allowed us to include individuals who were members of groups that are culturally different (as exemplified by the results on the GEQ) but can read, write and speak English functionally enough to participate in the study. Interested readers are referred to Matsumoto and Hwang (2015) for more details concerning recruitment, discussion of cultural differences and citations relevant to ethnic differences in NVB.

6 The seven questions were as follows: (1) ‘Good morning/afternoon. What is the purpose of your visit today?’; (2) ‘Where will you be going?’; (3) ‘May I see a picture ID?’; (4) ‘Can you tell me in as much detail as possible what you plan to do in the file room today?’; (5) ‘Is that all?’; (6) ‘Do you intend to engage in any act that involves taking anything that does not belong to you?’; (7) ‘Is there anything else you wish to tell me about what you plan to do once you pass through this screening?’. As originally reported in Matsumoto et al. (2015), questions 4, 5 and 6 were those that are diagnostic, as those who have not been assigned to steal the check (the truthtellers) must answer them truthfully whereas those who have been assigned to steal the check (the liars) have to lie. These were the three questions which were analyzed in the present study.

7 Sample sizes for specific analyses varied because of the differing number of missing cases due to technical issues in the various methods of data extraction, differences in source record availability (for whole body movements) and differences in cases with no interview contamination.

8 Given 21 univariate tests computed, at α = .05, 21 × 5% = 1.05 tests should attain an α ≤ .05 by chance; in reality, 4 tests attained this; at α = .10 (trending toward significance), 21 × 10% = 2.10 tests should attain an α ≤ .10 by chance; in reality, 7 tests attained this.

9 However, there are also real differences in the depth and quality of memories, as memories of the past have actually occurred and involve the encoding of facts, sensations, emotions and other associations, little of which exists for future intent. Likely for this reason, cognitive load approaches to detecting lies about the future may not be as effective as lies about the past, as reported by Fenn, McGuire, Langben, and Blandón-Gitlin (2015).

Additional information

Funding

This work was funded by the Transportation Security Administration [grant no. HSTS04-16-C-CT9002].