Respiration Line Length Research Articles

The effect of retroactive memory interference on the P300-based Complex Trial Protocol (CTP)

In a P300-based concealed information test (CIT), an increased response to a crime-related “probe” item of interest suggests concealed knowledge. Because the CIT's detection ability is based on knowledgeable parties recognizing the key item, weakening the crime memory might decrease probe identifiability and reduce diagnostic power. Research on retroactive memory interference (RI) has shown that acquiring new information after encoding a memory can degrade the original memory, which suggests that RI might pose a threat to CITs. To test this, Gronau et al. (2015) had participants complete a mock-crime, followed by either a control task or a RI manipulation task, intended to impair the crime memory. Both the simple guilty control and RI groups were subdivided into three time delay conditions: 1/3 of participants immediately completed the task and CIT, another 1/3 completed the task and returned a week later for the CIT, and the remaining participants completed both the task and CIT a week later. Results showed that RI reduced memory of crime details and skin conductance responses, while respiration line length was unaffected. Here, we extend Gronau et al. (2015), using the Complex Trial Protocol (CTP) version of the P300-based CIT, to investigate the influence of RI on recognition. The CIT effect was obvious in all six group × time delay subconditions, as evidenced by their significantly larger probe vs. irrelevant amplitudes, high percentage of bootstrapped iterations where probe > irrelevants, bootstrapped mean amplitude differences, and satisfactory hit rates. However, these indices of the CIT effect did not differ based on group or time delay, as was the case for target response error rates and P300 latencies. The only outcome of interest to vary by group or time delay was behavioral response times: both probe and combined irrelevant responses were delayed in the control (simple guilty) group. Thus, the evidence suggests that the RI manipulation used here does not threaten the P300-based CTP's accuracy. Results are considered as they compare to previous work, and limitations and possible explanations for our results are discussed.

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.

Psychophysiological Responses of People with Psychopathic Tendencies to the Concealed Information Test.

This study was designed to investigate differences in psychophysiological responses among individuals with psychopathic tendencies. A total 40 students were participated and were divided into two groups based on Levenson Self-Report Psychopathy Scale (LSRP) scores: a high psychopathic tendency group selected from the top 5% of LSRP scores, and a low psychopathic tendency group selected from the bottom 5% of LSRP scores. All participants were instructed to perform a mock crime and complete the concealed information test (CIT). Results indicate that significant differences between crime-relevant questions and irrelevant questions were observed for respiration line length and skin conductance response in both groups, but heart rate did not significantly differ between groups. There were no differences in psychophysiological responses between the groups. In conclusion, CIT was found to be an effective method for detecting crime-relevant information in individuals with psychopathic tendencies.

Unraveling the roles of orienting and inhibition in the Concealed Information Test.

The Concealed Information Test (CIT) is a well-validated tool for physiological and behavioral detection of concealed knowledge. Two distinct theoretical frameworks have been proposed to explain the differential responses to the concealed critical items: orienting response theory versus arousal inhibition theory. klein Selle, Verschuere, Kindt, Meijer, and Ben-Shakhar (2016), however, argued for a response fractionation model and showed that, while the skin conductance reflects pure orienting, both the respiratory and heart rate measures reflect arousal inhibition. The present study intends to (1) provide a constructive replication of klein Selle et al. (2016) using the autobiographical CIT, and (2) extend their work by testing an additional prediction derived from orienting theory, using an item-salience manipulation. One hundred and nine participants were tested on four high salient and four low salient identity items. Half of the participants were motivated to hide their identity (orienting + arousal inhibition), while the other half were motivated to reveal their identity (orienting only). Confirming earlier findings, the results revealed a fractionation between the different measures: while the skin conductance response (SCR) increased to a similar extent in the two motivational conditions, the respiration line length (RLL) shortened and the heart rate (HR) decelerated solely in the conceal condition. Moreover, while the SCR was larger for high than for low salient critical items, the RLL and HR responses were similar for these two item types. These data led us to conclude that, in the CIT, the skin conductance measure reflects orienting and the respiratory and heart rate measures reflect arousal inhibition.

Contributions of personality dimensions to spontaneous and deliberate information processing in the guilty actions test

The contribution of the Big-Five personality dimensions and locus of control to examinees' physiological responses in the Concealed Information polygraph Test (CIT) was examined for the first time. One hundred and twenty undergraduate students who completed Big Five personality and locus of control questionnaires were instructed to commit a mock theft. They were subsequently tested in the Guilty Actions polygraph Test, a modified version of the CIT. Each of the six sets of items (questions) was repeated twice. Results showed that introversion predicted enhanced Skin Conductance Responses (SCRs) to the critical items only for the first repetition of the first 3 questions which was explained by sensitivity to orienting responses. In contrast, extraversion was linked to Finger Pulse Waveform Length (FPWL) responses to the first repetition of the first 3 questions and was explained by extended and more deliberate information processing due to increased interest in the experiment. Participants high in openness to experience, characterized by intellectual curiosity, responded more strongly on FPWL throughout the test. Lower Neuroticism scores predicted enhanced Respiration Line Length (RLL) responses in the first repetition of the first 3 questions. Internal locus of control predicted higher tonic skin conductance level before and throughout the test. Results were explained by different information processing styles associated with these personality dimensions during various stages of the test.

Extracting critical information from group members' partial knowledge using the Searching Concealed Information Test.

The Concealed Information Test (CIT) is a psychophysiological method designed to detect information that an individual cannot or does not wish to reveal. The present study used a version of the CIT, the Searching Concealed Information Test (SCIT), to extract information from partial information that participants possessed on a planned jailbreak. In the first experiment, 52 undergraduate students were randomly, but not equally, allocated into 15 different clusters of partial knowledge. In each, participants possessed knowledge about 2 of 6 critical items. Using a lenient decision rule, and a combined measure defined as the mean of 3 individual measures (skin conductance response amplitude, finger pulse, and respiration line length) 5 of the 6 critical items were identified. Experiment 2 extended the first experiment to unequal proportions of critical knowledge. Forty-six undergraduate students were randomly allocated into 25 clusters of partial knowledge in which 0, 1, 2, 3, or 6 pieces of information were known. Using the same lenient decision rule and the combined measure, all 6 items were identified. It was suggested that the Group SCIT is capable of assembling a comprehensive picture out of partial information possessed by informed innocent participants. (PsycINFO Database Record

Memory detection with the Concealed Information Test: a meta analysis of skin conductance, respiration, heart rate, and P300 data.

The Concealed Information Test (CIT) uses psychophysiological measures to determine the presence or absence of crime-related information in a suspect's memory. We conducted a meta-analysis on the validity of the CIT based on four physiological measures-skin conductance response (SCR), respiration line length (RLL), changes in heart rate (HR), and enhanced amplitudes of the P300 component of the event-related potential (P300). This meta-analysis relied on laboratory studies that used either the mock-crime or the personal-item paradigm. Results showed a mean effect size (d*) of 1.55 for SCR, 1.11 for RLL, 0.89 for HR, and 1.89 for P300. However, P300 outperformed SCR only in the personal-item paradigm, but not in the mock-crime paradigm. Motivation level, number of questions, publication year, and the inclusion of innocent participants emerged as significant moderators for the SCR, while only the type of paradigm used moderated the P300 effect.

Psychophysiology of False Memories in a Deese-Roediger-McDermott Paradigm with Visual Scenes

Remembering something that has not in fact been experienced is commonly referred to as false memory. The Deese-Roediger-McDermott (DRM) paradigm is a well-elaborated approach to this phenomenon. This study attempts to investigate the peripheral physiology of false memories induced in a visual DRM paradigm. The main research question is whether false recognition is different from true recognition in terms of accompanying physiological responses.Sixty subjects participated in the experiment, which included a study phase with visual scenes each showing a group of interrelated items in social contexts. Subjects were divided into an experimental group undergoing a classical DRM design and a control group without DRM manipulation. The control group was implemented in order to statistically control for possible biases produced by memorability differences between stimulus types. After a short retention interval, a pictorial recognition phase was conducted in the manner of a Concealed Information Test. Simultaneous recordings of electrodermal activity, respiration line length, phasic heart rate, and finger pulse waveform length were used. Results yielded a significant Group by Item Type interaction, showing that true recognition is accompanied by greater electrodermal activity than false recognition.Results are discussed in the light of Sokolov's Orienting Reflex, the Preliminary Process Theory and the Concealed Information Test. Implications and restrictions of the introduced design features are critically discussed. This study demonstrates the applicability of measures of peripheral physiology to the field of false memory research.

Study regarding psychophysiological reactivity values depending on subject's gender in polygraph testing

In a quasi-experimental research we aimed at highlighting differences regarding psychophysiological reactivity in polygraph examinations, dependent on the GENDER variable. Two paired-samples have been used, with a volume of 31 participants, diagnosed as deceptive in real cause examinations. Women have a higher mean value for: Electrodermal Amplitude (AEDA)(t(30)=3.72, p=001, dCohen= 0.50); Electrodermal Line Length (LLEDA)(t(30)=-2.34, p=.026, d= 0.14); Scoring of the Electrodermal Amplitude (SCORING AEDA) (t(30)= -3.64, p=.001, d= 0.30); Scoring of the Electrodermal Line Length (SCORING LLEDA)(t(30)= -2.29, p=.029, d= 0.58).Men have a higher mean value for: Respiration Line Length(RLL) (t(30)=85.32, p=.006, d= 0.60); Mean Amplitude of Brachial Pulse (ACA) (t(30)= 4.31, p<.001, d=0.23). The results of the present study can provide useful information in the interpretation of psychophysiological data in order to increase the safety and precision level in diagnostic formulation in polygraph testing.

Face and voice as social stimuli enhance differential physiological responding in a concealed information test.

Attentional, intentional, and motivational factors are known to influence the physiological responses in a Concealed Information Test (CIT). Although concealing information is essentially a social action closely related to motivation, CIT studies typically rely on testing participants in an environment lacking of social stimuli: subjects interact with a computer while sitting alone in an experimental room. To address this gap, we examined the influence of social stimuli on the physiological responses in a CIT. Seventy-one participants underwent a mock-crime experiment with a modified CIT. In a between-subjects design, subjects were either questioned acoustically by a pre-recorded male voice presented together with a virtual male experimenter’s uniform face or by a text field on the screen, which displayed the question devoid of face and voice. Electrodermal activity (EDA), respiration line length (RLL), phasic heart rate (pHR), and finger pulse waveform length (FPWL) were registered. The Psychopathic Personality Inventory – Revised (PPI-R) was administered in addition. The differential responses of RLL, pHR, and FPWL to probe vs. irrelevant items were greater in the condition with social stimuli than in the text condition; interestingly, the differential responses of EDA did not differ between conditions. No modulatory influence of the PPI-R sum or subscale scores was found. The results emphasize the relevance of social aspects in the process of concealing information and in its detection. Attentional demands as well as the participants’ motivation to avoid detection might be the important links between social stimuli and physiological responses in the CIT.

Improved method for calculating the respiratory line length in the Concealed Information Test

The Concealed Information Test (CIT) assesses an examinee's knowledge about a crime based on response differences between crime-relevant and crime-irrelevant items. One effective measure in the CIT is the respiration line length, which is the average of the moving distances of the respiration curve in a specified time interval after the item onset. However, the moving distance differs between parts of a respiratory cycle. As a result, the calculated respiration line length is biased by how the parts of the respiratory cycles are included in the time interval. To resolve this problem, we propose a weighted average method, which calculates the respiration line length per cycle and weights it with the proportion that the cycle occupies in the time interval. Simulation results indicated that the weighted average method removes the bias of respiration line lengths compared to the original method. The results of experimental CIT data demonstrated that the weighted average method significantly increased the discrimination performance as compared with the original method. The weighted average method is a promising method for assessing respiration changes in response to question items more accurately, which improves the respiration-based discrimination performance of the CIT.

An interfering n-back task facilitates the detection of concealed information with EDA but impedes it with cardiopulmonary physiology

One approach to investigate psychophysiological processes occurring in the Concealed Information Test (CIT) is to use a parallel task, which engages specific mental activity in addition to the CIT. In the present study, the influence of an interfering n-back task on the physiological responses in a Concealed Information Test (CIT) was investigated. Forty participants underwent a mock-crime experiment with a modified CIT. In a within-subject design, the CIT was applied in blocks with and without an additional n-back task. Electrodermal activity (EDA), respiration line length (RLL), heart rate (HR), and finger pulse waveform length (FPWL) were registered. Reaction times in the n-back task and the CIT were recorded. The parallel task enhanced the differential EDA response to probe vs. irrelevant items, while it diminished the response differences for RLL and phasic HR. Results shed light upon working-memory-related processes in the CIT. The diverging effects of the interfering mental activity on electrodermal and cardiopulmonary measures, if replicable, might contribute to a better understanding of the psychophysiological responsiveness underlying the CIT.

Combining physiological measures in the detection of concealed information

Meta-analytic research has confirmed that skin conductance response (SCR) measures have high validity for the detection of concealed information. Furthermore, cumulating research has provided evidence for the validity of two other autonomic measures: Heart rate (HR) and Respiration Line Length (RLL). In the present report, we compared SCR detection efficiency with HR and RLL, and investigated whether HR and RLL provide incremental validity to electrodermal responses. Analyses were based on data from 7 different samples covering 275 guilty and 53 innocent examinees. Results revealed that the area under the ROC curve was significantly higher for SCR than for HR and RLL. A weighted combination of these measures using a logistic regression model yielded slightly larger validity coefficients than the best single measure. These results proved to be stable across different protocols and various samples.

An interfering Go/No-go task does not affect accuracy in a Concealed Information Test

Following the idea that response inhibition processes play a central role in concealing information, the present study investigated the influence of a Go/No-go task as an interfering mental activity, performed parallel to the Concealed Information Test (CIT), on the detectability of concealed information. 40 undergraduate students participated in a mock-crime experiment and simultaneously performed a CIT and a Go/No-go task. Electrodermal activity (EDA), respiration line length (RLL), heart rate (HR) and finger pulse waveform length (FPWL) were registered. Reaction times were recorded as behavioral measures in the Go/No-go task as well as in the CIT. As a within-subject control condition, the CIT was also applied without an additional task. The parallel task did not influence the mean differences of the physiological measures of the mock-crime-related probe and the irrelevant items. This finding might possibly be due to the fact that the applied parallel task induced a tonic rather than a phasic mental activity, which did not influence differential responding to CIT items. No physiological evidence for an interaction between the parallel task and sub-processes of deception (e.g. inhibition) was found. Subjects' performance in the Go/No-go parallel task did not contribute to the detection of concealed information. Generalizability needs further investigations of different variations of the parallel task.

Efficacy of Repeated Psychophysiological Detection of Deception Testing

Physiological measures were recorded during repeated psychophysiological detection of deception (PDD) tests to determine if reaction levels change with test repetition. Two groups of 22 healthy male subjects completed six peak of tension PDD tests on each of two test days. A minimum between test day interval of six days was maintained. The treatment group was programmed to respond deceptively to one of seven test questions while the control group was programmed to respond truthfully to all questions. The respiration and galvanic skin resistance (GSR) line lengths, GSR peak response amplitude and latency, and cardiovascular inter-beat-interval (IBI) were calculated for each response. Analyses indicated that, except for GSR peak response latency, differential physiological reactivity during a PDD test did not change significantly over repeated tests or days; there was a decrease in average respiration line lengths at the initial test(s) of each day; and differential changes in average respiration line length, GSR peak latency, and cardiovascular IBI responses corresponded to deception. Power analyses were calculated to assist in result interpretation. It is suggested that PDD decision accuracy, concerning subject veracity, should not decrease during repeated testing.

The Accuracy of Human Decisions and Objective Measurements in Psychophysiological Detection of Knowledge

I examined the relative detection efficiency of three measurements--skin resistance response (SRR) amplitude, respiration line length (RLL), and human respiration response evaluation (RRE)--in a guilty knowledge experiment. Thirty-two subjects were presented with lists of personal information in which only one of five items was correct. Subjects were instructed to try to avoid detection of the relevant items in the polygraph test. All three measurements discriminated better than chance between relevant and neutral items, with the objectively measured SRR and RLL superior to the subjective RRE. When SRR and RLL were compared for their relative efficiency, the former yielded better detection. The differentiation was even better with a measure that combined the SRR and the RLL. The results are discussed with respect to previous findings and practical implications.

Detection measures in real-life criminal guilty knowledge tests.

The present study provides a first attempt to compare the validity of the respiration line length (RLL) and skin resistance response (SRR) amplitude in real-life criminal guilty knowledge tests (GKTs). GKT records of 40 innocent and 40 guilty Ss, for whom actual truth was established by confession, were assessed for their accuracy. When a predefined decision rule was used and inconclusive decisions were excluded, 97.4% of the innocent Ss and 53.3% of the guilty Ss were correctly classified with the SRR measure. For the RLL measure, the respective results were 97.2% and 53.1%. The combination of both measures improved detection of guilty Ss to 75.8% and decreased detection of innocent Ss to 94.1%. The combined measure seems to be a more useful means of identifying guilty suspects than each physiological measure alone. The results elaborate and extend those obtained in a previous field study conducted by Elaad (1990).