Nonverbal cues to deception: insights from a mock crime scenario in a Chinese sample

Nonverbal behaviors could play a crucial role in detecting deception, yet existing studies on deception cues have largely centered on Western populations, predominantly university students, thus neglecting the influence of cultural and sample diversity. To address this gap, our study explored deception cues within an Asian cultural setting, utilizing a mock crime paradigm. Our sample comprised Chinese participants, including both men and women with various socioeconomic status (SES) backgrounds. Our findings revealed that compared to truth tellers, liars exhibited heightened emotions and an increased cognitive load. Furthermore, liars showed a higher frequency of self-adaptors and a longer duration of gaze aversion. Our findings contribute to a more profound understanding of deception cues within Asian culture and have implications for practical fields such as criminal interrogation.

The Detection of Malingered Amnesia: An Approach Involving Multiple Strategies in a Mock Crime

The nature of amnesia in the context of crime has been the subject of a prolonged debate. It is not uncommon that after committing a violent crime, the offender either does not have any memory of the event or recalls it with some gaps in its recollection. A number of studies have been conducted in order to differentiate between simulated and genuine amnesia. The recognition of probable malingering requires several inferential methods. For instance, it typically involves the defendant's medical records, self-reports, the observed behavior, and the results of a comprehensive neuropsychological examination. In addition, a variety of procedures that may detect very specific malingered amnesia in crime have been developed. In this paper, we investigated the efficacy of three techniques, facial thermography, kinematic analysis, and symptom validity testing in detecting malingering of amnesia in crime. Participants were randomly assigned to two different experimental conditions: a group was instructed to simulate amnesia after a mock homicide, and a second group was simply asked to behave honestly after committing the mock homicide. The outcomes show that kinematic analysis and symptom validity testing achieve significant accuracy in detecting feigned amnesia, while thermal imaging does not provide converging evidence. Results are encouraging and may provide a first step towards the application of these procedures in a multimethod approach on crime-specific cases of amnesia.

Evaluative Observation in a Concealed Information Test

The Concealed Information Test (CIT) is a valid method to detect hidden knowledge by means of psychophysiological measures. Concealing information is always a social behavior; yet, the role of social aspects has barely been investigated in recent CIT research favoring standardized, computer-based experiments. Evaluative observation is known to influence social behavior as well as physiological measures; examining the impact of evaluative observation on physiological responding in a CIT is the aim of this study. Sixty-three students completed a mock-crime and then underwent a CIT. In a between-subjects manipulation, half of the participants were observed through a camera and were faced with the real-time video of the experimenter watching them while completing the CIT. The other half completed the CIT without observation and video. Electrodermal activity, respiration line length, phasic heart rate, and finger pulse waveform length were registered. A specific questionnaire captured the individual fear of negative evaluation. Typical differential CIT responses occurred in both groups and with each measure. Contrary to expectations, differential CIT responses did not differ between groups. No modulatory influence of the fear questionnaire score on physiological responding was found. A ceiling effect, involving high attention and high motivation to avoid detection as well as high arousal in both groups due to the CIT procedure per se is discussed as explanation for these results, while the independence of the orienting reflex of social and motivational influence appears less likely in the light of previous literature.

Emotional Arousal at Memory Encoding Enhanced P300 in the Concealed Information Test

Previous studies have reported that the concealed information test (CIT) is a reliable and powerful method for detecting information. However, the external validity of the CIT studies has not been fully proven. In particular, few studies have examined the effects of emotional arousal at memory encoding on physiological responses in the CIT. The present study investigated the influence on the CIT of the magnitude of emotional arousal at memory encoding of a mock crime, using the P300 component of the event-related brain potential (ERP). In accord with the assumptions of excitation-transfer theory, we presented emotionally arousing pictures before a mock crime. Participants were randomly assigned to either a high emotional arousal group (n = 10) or a low emotional arousal group (n = 11), viewing pictures expected to arouse emotion at a high or low level, respectively. Subsequently, all participants enacted the same mock crime, in which they were instructed to stab a pillow with a sharp-edged tool (e.g., a kitchen knife or ice pick) as if harassing a mannequin lying on a bed. After the antecedent emotional experience, the P300-based CIT was conducted. Participants in the high arousal group showed significantly greater P300 amplitudes in response to a probe stimulus compared with the low arousal group. No differences were found between the groups in response to irrelevant stimuli. These results support the notion that emotional arousal influences the P300 in the CIT paradigm.

A functional analysis of deception detection of a mock crime using infrared thermal imaging and the Concealed Information Test

The purpose of this study was to utilize thermal imaging and the Concealed Information Test to detect deception in participants who committed a mock crime. A functional analysis using a functional ANOVA and a functional discriminant analysis was conducted to decrease the variation in the physiological data collected through the thermal imaging camera. Participants chose between a non-crime mission (Innocent Condition: IC), or a mock crime (Guilty Condition: GC) of stealing a wallet in a computer lab. Temperature in the periorbital region of the face was measured while questioning participants regarding mock crime details. Results revealed that the GC showed significantly higher temperatures when responding to crime relevant items compared to irrelevant items, while the IC did not. The functional ANOVA supported the initial results that facial temperatures of the GC elevated when responding to crime relevant items, demonstrating an interaction between group (guilty/innocent) and relevance (relevant/irrelevant). The functional discriminant analysis revealed that answering crime relevant items can be used to discriminate guilty from innocent participants. These results suggest that measuring facial temperatures in the periorbital region while conducting the Concealed Information Test is able to differentiate the GC from the IC.

P300 amplitudes in the concealed information test are less affected by depth of processing than electrodermal responses

The Concealed Information Test (CIT) has been used in the laboratory as well as in field applications to detect concealed crime related memories. The presentation of crime relevant details to guilty suspects has been shown to elicit enhanced N200 and P300 amplitudes of the event-related brain potentials (ERPs) as well as greater skin conductance responses (SCRs) as compared to neutral test items. These electrophysiological and electrodermal responses were found to incrementally contribute to the validity of the test, thereby suggesting that these response systems are sensitive to different psychological processes. In the current study, we tested whether depth of processing differentially affects N200, P300, and SCR amplitudes in the CIT. Twenty participants carried out a mock crime and became familiar with central and peripheral crime details. A CIT that was conducted 1 week later revealed that SCR amplitudes were larger for central details although central and peripheral items were remembered equally well in a subsequent explicit memory test. By contrast, P300 amplitudes elicited by crime related details were larger but did not differ significantly between question types. N200 amplitudes did not allow for detecting concealed knowledge in this study. These results indicate that depth of processing might be one factor that differentially affects central and autonomic nervous system responses to concealed information. Such differentiation might be highly relevant for field applications of the CIT.