Deception and truth detection when analyzing nonverbal and verbal cues

In this article, I present my view on the significant developments and theoretical/empirical tipping points in nonverbal and verbal deception and lie detection from the last 30 years and on prospects for future research in this domain. I discuss three major shifts in deception detection research: (a) From observing target persons' nonverbal behavior to analyzing their speech; (b) from lie detection based on differences between truth tellers and liars' levels of arousal to lie detection based on the different cognitive processes or strategies adopted to appear convincing; and (c) from passively observing target persons to actively interviewing them to elicit or enhance verbal cues to deceit. Finally, I discuss my ideas for future research, focusing on initiatives from my own lab. Hopefully, this will stimulate other researchers to explore innovative ideas in the verbal deception research domain, which already has seen so much progress in the last decade.     

The effect of newly trained verbal and nonverbal labels for the cues in probabilistic category learning

Learning in a well-established paradigm of probabilistic category learning, the weather prediction task, has been assumed to be mediated by a variety of strategies reflecting explicit learning processes, such as hypothesis testing, when it is administered to young healthy participants. Higher categorization accuracy has been observed in the task when explicit processes are facilitated. We hypothesized that furnishing verbal labels for the cues would boost the formation, testing, and application of verbal rules, leading to higher categorization accuracy. We manipulated the availability of cue names by training separate groups of participants for three consecutive days to associate hard-to-name artificial auditory cues to pseudowords or to hard-to-name ideograms, or to associate stimulus intensity with colors; a fourth group remained unexposed to the cues. Verbal labels, cue individuation, and exposure to the stimulus set each had an additive effect on categorization performance in a subsequent 200-trial session of the weather prediction task using these auditory cues. This study suggests that cue nameability, when controlled for cue individuation and cue familiarity, has an effect on hypothesis-testing processes underlying category learning.     

Rapid judgements in assessing verbal and nonverbal cues: their potential for deception researchers and lie detection

In the present study it was investigated to what extent observers (i) could make rapid yet reliable and valid judgements of the frequency of verbal and nonverbal behaviours of interviewees (liars and truth tellers) and (ii) detect deceit after making these rapid judgements. Five observers watched 52 videoclips of 26 liars and 26 truth tellers. The findings revealed that rapid judgements were reliable and valid. They also revealed that observers were able to detect truths and lies well above the level of chance after making these rapid judgements (74% accuracy rate was found). The implications of these findings for deception researchers and lie detection are discussed. Copyright © 2004 John Wiley & Sons, Ltd.     

Encoding and decoding nonverbal cues of emotion.

Subjects ("senders") encoded six emotions twice, first via facial expressions and second via tone of voice. These expressions were recorded and presented for decoding to the senders and an additional group of judges. Results were as follows: (a) the ability to encode and the ability to decode both visual and auditory cues were significantly related; (b) the relationship between encoding and decoding cues of the same emotion appeared low or negative; (c) the ability to decode visual cues was significantly related to the ability to decode auditory cues, but the correlations among encoding (and decoding) scores on different emotions were low; (d) females were slightly better encoders, and significantly better decoders, than males; (e) acquaintance between sender and judge improved decoding scores among males but not among females; (f) auditory decoding scores were higher than visual decoding scores, particularly among males; (g) auditory decoding scores were relatively high if sender and judge were of the same sex, while visual decoding scores were relatively high if sender and judge were of opposite sexes; (h) decoding scores varied according to channel of communication and type of emotion transmitted.     

Modality-specific interference with verbal and nonverbal stimulus information

Subjects recalled both letters and the locations of letters in 2 by 3 and 1 by 6 matrices after either no interfering activity or visual, auditory, or kinesthetic interfering activity. Results for each type of matrix indicated the presence of selective auditory (verbal) interference with the recall of letter identity and selective visual and kinesthetic interference with the recall of letter location. Supplementary correlational analyses indicated that the presence of such a dual encoding strategy was most consistent across subjects for the 2 by 3 matrix. Although the results indicated that use of different modes of representation was related to the verbal-nonverbal nature of the information, it was shown that the structure of the stimulus array also affected the nature of the representation.     

Matched false-belief performance during verbal and nonverbal interference

Language has been shown to play a key role in the development of a child's theory of mind, but its role in adult belief reasoning remains unclear. One recent study used verbal and nonverbal interference during a false-belief task to show that accurate belief reasoning in adults necessarily requires language (Newton & de Villiers, 2007). The strength of this inference depends on the cognitive processes that are matched between the verbal and nonverbal inference tasks. Here, we matched the two interference tasks in terms of their effects on spatial working memory. We found equal success on false-belief reasoning during both verbal and nonverbal interference, suggesting that language is not specifically necessary for adult theory of mind.     

Effects of body mass index and education on verbal and nonverbal memory

We previously reported that higher education protects against executive dysfunction related to higher body mass index (BMI) in younger, but not older, adults. We now extend the previous analyses to verbal and nonverbal memory. Fifty-nine healthy, dementia-free community-dwelling adults ranging in age from 18 to 81 years completed the Hopkins Verbal Learning Test – Revised (HVLT-R) and the Brief Visuospatial Memory Test – Revised (BVMT-R). Self-reported years of education served as a proxy for cognitive reserve. We found that more highly educated individuals maintained their BVMT-R immediate recall performance across the range of BMI, but in less educated individuals, higher BMI was associated with worse performance. Our findings suggest that education may play a protective role against BMI-related nonverbal learning deficits, similar to previous reports for verbal memory and executive functioning. Results highlight the importance of considering educational background when determining the risk for BMI-related cognitive impairment in clinical settings.     

On problems of context and attribution in verbal reasoning

Investigated the effect of the verb on inferences in reasoning tasks with conditionals. Subjects were 60 pupils, both male and female, aged 17 to 18 years. Six verbs (buy, have, understand, ignore, hate, avoid) served as independent variables in conditional tasks consisting of two premises. The results which are statistically, highly significant, show an effect due to the verb depending upon the logical form of the task (2Î = 86.1, df= 30). indicate that certain semantic characteristics implicit in verbs determine the way in which a reasoning task is interpreted. A second experiment investigated why verbs differ in this way. Interviews were carried out with subjects using the verbs ‘buy’ and ‘ignore’. It is suggested that implicit meanings acquired through processes of social attribution play an essential role in verbal reasoning. In the present case, such attributions concern the depositional and episodic character of verbs and appear to be responsible for the interpretation of the premises of our tasks. It is concluded that any logical model aiming at an adequate representation of language in reasoning must take these implicit social attributions into account.     

Identifying emergent leaders from verbal and nonverbal communications.

Subject/observers were accurate in identifying emergent leadership hierarchies on four leadership dimensions when provided records of target groups' meetings containing only verbal communications, only nonverbal communications, or both types of behavior. With knowledge of participation rates controlled by covariance, the subject/observers' accuracy scores retained significance in three of the information conditions demonstrating the presence of verbal and nonverbal leadership cues independent of participation rates. The value of verbal and nonverbal communications to identifying leaders varied with the type of leadership hierarchy being identified. The findings are presumed to hold for leader selection as well. The author proposes that the question of why a group member has emerged to fulfill a leadership role in a group be studied from the point of view of group members' selecting leaders or permitting emergence rather than leaders emitting behaviors.     

Dichhaptic hand-order effects with verbal and nonverbal tactile stimulation

The palms of normal right-handed subjects were stimulated dichhaptically, i.e., with competing, bimanually presented tactile stimuli consisting of pairs of letters, pairs of digits, or pairs of line orientations. The subjects were required to identify both stimuli in a particular order, and order of report was compared between hands and across stimulus materials. Results indicated right-hand superiority for letters and left-hand superiority for lines; no hand differences occurred for digits. However, observed differences between hands appeared with second reports only, suggesting that measures of tactile storage are more sensitive to laterality differences than measures closer in time to actual stimulation.