Attempting to hide our real thoughts: electrophysiological evidence from truthful and deceptive responses during evaluation

Neuroelectric Correlates of Human Sexuality: A Review and Meta-Analysis

Many reviews on sexual arousal in humans focus on different brain imaging methods and behavioral observations. Although neurotransmission in the brain is mainly performed through electrochemical signals, there are no systematic reviews of the electrophysiological correlates of sexual arousal. We performed a systematic search on this subject and reviewed 255 studies including various electrophysiological methods. Our results show how neuroelectric signals have been used to investigate genital somatotopy as well as basic genital physiology during sexual arousal and how cortical electric signals have been recorded during orgasm. Moreover, experiments on the interactions of cognition and sexual arousal in healthy subjects and in individuals with abnormal sexual preferences were analyzed as well as case studies on sexual disturbances associated with diseases of the nervous system. In addition, 25 studies focusing on brain potentials during the interaction of cognition and sexual arousal were eligible for meta-analysis. The results showed significant effect sizes for specific brain potentials during sexual stimulation (P3: Cohen's d = 1.82, N = 300, LPP: Cohen's d = 2.30, N = 510) with high heterogeneity between the combined studies. Taken together, our review shows how neuroelectric methods can consistently differentiate sexual arousal from other emotional states.

The role of conflict processing mechanism in deception responses

A considerable number of studies have described the potential neural mechanism of deception, but most deception studies have relied upon deception from experimental supervisor instruction. Experimental control (participants follow instructions to deceive without any risk) means that the deception occurs in a way that does not come close to the real deception. In the current study, a neural imaging experiment on deception closer to the real deception was conducted. Event-related potential (ERP) and event-related spectral perturbation (ERSP) techniques were used to explore the neural mechanism of deception. The results showed that deceptive response evoked larger medial-frontal negativity (MFN) and smaller response-locked positivity (RLP) than truthful response. We interpret these findings to indicate that conflict detection and emotional processing are associated with deception. In addition, magnitudes of alpha and beta oscillations after the deceptive response were significantly smaller than those after the truthful response, demonstrating that deception is associated with neural oscillations reflecting conflict adjustment. The results comprehensively characterized the physiological properties of the brain oscillations elicited by a deceptive response and provided a theoretical foundation for detection in practical applications.

Automaticity of Early Sexual Attention: An Event-Related Potential Study

A promising line of research on forensic assessment of paraphilic sexual interest focuses on behavioral measures of visual attention using sexual stimuli as distractors. The present study combined event-related potentials (ERPs) with behavioral measures to investigate whether detection of a hidden sexual preference can be improved with ERPs. Normal variants of sexual orientation were used for a proof-of-concept investigation. Accordingly, 40 heterosexual and 40 gay men participated in the study. Within each group, half of the participants were instructed to hide their sexual orientation. The results showed that a match between sexual orientation and stimulus delays responses and influences ERP before motor responses. Late ERP components showed higher potential in differentiating hidden sexual preferences than motor responses, thereby showing how ERPs can be used in combination with reaction time measures to potentially facilitate the detection of hidden sexual preferences.

Cognitive processes during deception about attitudes revisited: a replication study

Event-related potential (ERP) studies about deception often apply recognition tasks. It remains questionable whether reported ERP patterns and cognitive processes can be generalized to other contexts. As the study by Johnson et al. (2008) fills this gap by investigating deception regarding attitudes, we tried to replicate it. Participants (N = 99) were instructed to lie or tell the truth about their attitudes. We obtained the same results as Johnson et al. (2008): lies were accompanied by enhanced medial frontal negativities (MFN) and suppressed late positive components (LPCs) indicating that lying relied on stronger cognitive control processes and response conflicts than being honest. The amplitudes of pre-response positivities (PRP) were reduced for lies implying that lies about attitudes were accompanied by strategic monitoring. MFN amplitudes increased and LPC amplitudes decreased for lies about positively valued items revealing that lying about positively valued items is cognitively more challenging than lying about negatively valued items. As a new finding, MFN, LPC and PRP components were neither moderated by Machiavellianism nor by changes in the attitude ratings. The results indicate that LPC, MFN and PRP components are reliable indicators of the cognitive processes used during deception and that it is worthwhile to investigate them in further deception contexts.

The Electrocortical Signature of Successful and Unsuccessful Deception in a Face-to-Face Social Interaction

Deceptive behavior, and the evaluation of others' behavior as truthful or deceptive, are crucial aspects of human social interaction. We report a study investigating two participants in a social interaction, performing a deception task. The first participant, the "informant," made true or false autobiographical statements. The second participant, the "detective," then classified these statements as truth or lie. Behavioral data showed that detectives performed slightly above chance and were better at correctly identifying true as compared with deceptive statements. This presumably reflects the "truth bias": the finding that individuals are more likely to classify others' statements as truthful than as deceptive - even when informed that a lie is as likely to be told as the truth. Electroencephalography (EEG) was recorded from the informant. Event-related potential (ERP) analysis revealed a smaller contingent negative variation (CNV) preceding "convincing" statements (statements classified as true by the detective) compared to "unconvincing" statements (statements classified as lie by the detective) - irrespective of whether the statements were actually truthful or deceptive. This finding suggests a distinct electrocortical signature of "successful" compared to "unsuccessful" deceptive statements. One possible explanation is that the pronounced CNV indicates the individuals' higher "cognitive load" when processing unconvincing statements.

Internal cost of spontaneous deception revealed by ERPs and EEG spectral perturbations

Abundant literature has studied the behavioral and neural correlates of deception, but little research has focused on the internal cost of spontaneous deception. In the present study, the event-related potential and event-related spectral perturbations techniques were used to measure the internal cost of spontaneous deception by having participants perform a sender–receiver task in which they decided whether to send deceptive messages to increase their payoff from the task. Several important main findings emerged from this study. We observed a reward positivity (RewP) after senders sent the message, suggesting an integration of reward with associated cost after response in our task. Furthermore, spontaneous deception decreased the amplitude of the RewP and power in the delta and beta bands, whereas it increased the amplitude of power in the theta band, indicating that deception carried an internal cost that devalued individuals’ rewards.

Functional Connectivity Pattern Analysis Underlying Neural Oscillation Synchronization during Deception

To characterize system cognitive processes during deception, event-related coherence was computed to investigate the functional connectivity among brain regions underlying neural oscillation synchronization. In this study, 15 participants were randomly assigned to honesty or deception groups and were instructed to tell the truth or lie when facing certain stimuli. Meanwhile, event-related potential signals were recorded using a 64-channel electroencephalography cap. Event-related coherence was computed separately in four frequency bands (delta (1-3.5 Hz), theta (4-7 Hz), alpha (8-13 Hz), and beta (14-30 HZ)) for the long-range intrahemispheric electrode pairs (F3P3, F4P4, F3T7, F4T8, F3O1, and F4O2). The results indicated that deceptive responses elicited greater connectivities in the frontoparietal and frontotemporal networks than in the frontooccipital network. Furthermore, the deception group displayed lower values of coherence in the frontoparietal electrode pairs in the alpha and beta bands than the honesty group. In particular, increased coherence in the delta and theta bands on specific left frontoparietal electrode pairs was observed. Additionally, the deception group exhibited higher values of coherence in the delta band and lower values of coherence in the beta band on the frontotemporal electrode pairs than did the honesty group. These data indicated that the active cognitive processes during deception include changes in ensemble activities between the frontal and parietal/temporal regions.

Electrophysiological markers of working memory usage as an index for truth-based lies

People prefer to lie using altered truthful events from memory, perhaps because doing so can increase their credibility while reducing cognitive and working memory (WM) load. One possible way to counter such deceptive behavior is to track WM usage, since fabricating coherent lies or managing between truth and lies is likely to involve heavy WM load. In this study, participants memorized a list of words in the study session and used these old words to provide deceptive answers when cued later, in the testing session. Our behavioral results showed that people needed more time to make a deceptive response during the execution stage, and this prolonged deceptive reaction time (RT) was negatively correlated with each participant's WM capacity. Event-related potential findings showed a more negative-going frontal amplitude between the lie and truth conditions during the preparation stage, suggesting that WM preparatory processes can be detected long before a deceptive response is verbalized. Furthermore, we observed a larger positive frontal-central amplitude during the execution stage, which was negatively correlated with participants' lie-truth RT differences, suggesting that participants' efficiency in producing deceptive responses can be readily traced electrophysiologically. Together, these findings suggest that WM capacity and preparation are crucial to efficient lying and that their related electrophysiological signatures can potentially be used to uncover deceptive behaviors.

Neurocognitive mechanisms underlying deceptive hazard evaluation: An event-related potentials investigation

Deceptive behavior is common in human social interactions. Researchers have been trying to uncover the cognitive process and neural basis underlying deception due to its theoretical and practical significance. We used Event-related potentials (ERPs) to investigate the neural correlates of deception when the participants completed a hazard judgment task. Pictures conveying or not conveying hazard information were presented to the participants who were then requested to discriminate the hazard content (safe or hazardous) and make a response corresponding to the cues (truthful or deceptive). Behavioral and electrophysiological data were recorded during the entire experiment. Results showed that deceptive responses, compared to truthful responses, were associated with longer reaction time (RT), lower accuracy, increased N2 and reduced late positive potential (LPP), suggesting a cognitively more demanding process to respond deceptively. The decrement in LPP correlated negatively with the increment in RT for deceptive relative to truthful responses, regardless of hazard content. In addition, hazardous information evoked larger N1 and P300 than safe information, reflecting an early processing bias and a later evaluative categorization process based on motivational significance, respectively. Finally, the interaction between honesty (truthful/deceptive) and safety (safe/hazardous) on accuracy and LPP indicated that deceptive responses towards safe information required more effort than deceptive responses towards hazardous information. Overall, these results demonstrate the neurocognitive substrates underlying deception about hazard information.

Are Happy Faces Attractive? The Roles of Early vs. Late Processing

Facial attractiveness is closely related to romantic love. To understand if the neural underpinnings of perceived facial attractiveness and facial expression are similar constructs, we recorded neural signals using an event-related potential (ERP) methodology for 20 participants who were viewing faces with varied attractiveness and expressions. We found that attractiveness and expression were reflected by two early components, P2-lateral (P2l) and P2-medial (P2m), respectively; their interaction effect was reflected by LPP, a late component. The findings suggested that facial attractiveness and expression are first processed in parallel for discrimination between stimuli. After the initial processing, more attentional resources are allocated to the faces with the most positive or most negative valence in both the attractiveness and expression dimensions. The findings contribute to the theoretical model of face perception.

The motor cost of telling lies: electrocortical signatures and personality foundations of spontaneous deception

Although universal, lying is generally considered immoral behavior. Most neuroscience studies on lying sanction or instruct deceptive behaviors and thus might fail to acknowledge the significance of lie-related moral conflicts. By combining electroencephalogram (EEG) recordings with a novel paradigm in which participants decided freely whether to deceive another person, we have generated indices of the cognitive (reaction times and stimulus-locked event-related components) and moral (readiness potential and its correlations with deception-related personality traits) cost of spontaneous deception. Our data fail to support the consensus that deception is cognitively more demanding than truth telling, suggesting that spontaneous deception, as opposed to lying out of requirement, might not mandate additional cognitive workload. Interestingly, lying was associated with decreased motor readiness, an event-related potential (ERP) component that is linked to motor preparation of self-determined actions and modulated when we face moral dilemmas. Notably, this reduction was less extensive in manipulative participants and greater in those who cared highly about their impression management. Our study expands on previous findings on deception by associating a cortical marker of reduced preparation to act with individual differences in moral cognition.

Can you catch a liar? How negative emotions affect brain responses when lying or telling the truth

The capacity to deceive others is a complex mental skill that requires the ability to suppress truthful information. The polygraph is widely used in countries such as the USA to detect deception. However, little is known about the effects of emotional processes (such as the fear of being found guilty despite being innocent) on the physiological responses that are used to detect lies. The aim of this study was to investigate the time course and neural correlates of untruthful behavior by analyzing electrocortical indexes in response to visually presented neutral and affective questions. Affective questions included sexual, shameful or disgusting topics. A total of 296 questions that were inherently true or false were presented to 25 subjects while ERPs were recorded from 128 scalp sites. Subjects were asked to lie on half of the questions and to answer truthfully on the remaining half. Behavioral and ERP responses indicated an increased need for executive control functions, namely working memory, inhibition and task switching processes, during deceptive responses. Deceptive responses also elicited a more negative N400 over the prefrontal areas and a smaller late positivity (LP 550–750 ms) over the prefrontal and frontal areas. However, a reduction in LP amplitude was also elicited by truthful affective responses. The failure to observe a difference in LP responses across conditions likely results from emotional interference. A swLORETA inverse solution was computed on the N400 amplitude (300–400 ms) for the dishonest – honest contrast. These results showed the activation of the superior, medial, middle and inferior frontal gyri (BA9, 11, 47) and the anterior cingulate cortex during deceptive responses. Our results conclude that the N400 amplitude is a reliable neural marker of deception.

"Have You Ever Seen This Face?" - Individual Differences and Event-Related Potentials during Deception

Deception studies emphasize on the importance of event-related potentials (ERP) for a reliable differentiation of the underlying neuro-cognitive processes. The stimulus-locked parietal P3 amplitude has been shown to reflect stimulus salience but also attentional control available for stimulus processing. Known stimuli requiring truthful responses (targets) and known stimuli requiring deceptive responses (probes) were hypothesized to be more salient than unknown stimuli. Thus, a larger P3 was predicted for known truthful and deceptive stimuli than for unknown stimuli. The Medial Frontal Negativity (MFN) represents the amount of required cognitive control and was expected to be more negative to known truthful and deceptive stimuli than to unknown stimuli. Moreover, we expected higher sensitivity to injustice (SI-perpetrator) and aversiveness (Trait-BIS) to result in more intense neural processes during deception. N = 102 participants performed a deception task with three picture types: probes requiring deceptive responses, targets requiring truthful responses to known stimuli, and irrelevants being associated with truthful responses to unknown stimuli. Repeated-measures ANOVA and fixed-links modeling suggested a more positive parietal P3 and a more negative frontal MFN to deceptive vs. irrelevant stimuli. Trait-BIS and SI-perpetrator predicted an increase of the P3 and a decrease of the MFN from irrelevants to probes. This suggested an intensification of stimulus salience and cognitive control across picture types in individuals scoring either higher on Trait-BIS or higher on SI-perpetrator. In contrast, individuals with both higher Trait-BIS and higher SI-perpetrator scores showed a less negative probe-MFN suggesting that this subgroup invests less cognitive control to probes. By extending prior research we demonstrate that personality modulates stimulus salience and control processes during deception.

The presentation order of cue and target matters in deception study

Background

Two experimental procedures (cue-target and target-cue) were used in studying the processes of deception. How the task will affect participants' performances is not clear. This study was conducted to investigate the effect of the order of presentation of cue and target on the processes of deception.

Methods

A face evaluation task was employed to test and compare the order effect of the deception-indicating cue and the target stimulus in studying deception (i.e., which research procedure is more sensitive in distinguishing different experimental conditions and which is more likely to represent the deception process in daily life). Behavioral responses and event-related potentials (ERP) were recorded while participants made truthful and deceptive responses about their evaluation.

Results

Response-locked ERP showed that both deceptive conditions in cue-target and target-cue procedures elicited medial frontal negativities. However, the results in the ERP distribution regions, the ERP amplitudes and source estimation results were different in the two procedures. The cue-target procedure elicited a more negative ERP deflection between 40 ms and 90 ms over the central-frontal scalp regions than the target-cue procedures. Source localizations in cue-target were identified in three clusters, namely, medial frontal gyrus, dorsal anterior cingulate cortex, and ventral medial frontal gyrus. In the target-cue procedure, the sources were identified in the frontal areas.

Discussion

Different presenting orders of the cue and target stimuli induced different neural activities. Further, the cue-target procedure could represent the process of deception better than the target-cue procedure.