The validity of finger pulse line length for the detection of concealed information

doi:10.1016/j.ijpsycho.2008.07.015

International Journal of Psychophysiology

Volume 71, Issue 2, February 2009, Pages 118-123

https://doi.org/10.1016/j.ijpsycho.2008.07.015 Get rights and content

Abstract

Building on the orienting theory of the Concealed Information Test, Elaad and Ben-Shakhar [Elaad, E., & Ben-Shakhar, G. (2006). Finger pulse waveform length in the detection of concealed information. Int. J. Psychophysiol., 61, 226–234.] proposed a new measure for the detection of concealed information: finger pulse line length (FPLL). This measure is recorded with a plethysmograph and combines pulse rate and pulse amplitude. Because the validity of finger pulse amplitude is still not established, one could question the benefits of FPLL to well validated measures such as heart rate. In the present study we compared the validity of FPLL, finger pulse rate and finger pulse amplitude in the detection of concealed information. Male community volunteers (n = 77) who had acquired crime knowledge through a mock crime procedure, were instructed to deny knowledge in a Concealed Information Test. Skin conductance, finger pulse line length, finger pulse rate and amplitude, heart rate and respiration were recorded. FPLL validity was significantly higher than that of finger pulse amplitude and heart rate. These data, together with its ease of measurement, support the use of FPLL.

Section snippets

Participants

Seventy-nine male community volunteers were recruited through an advertisement in local magazines. We only recruited male participants because in Belgium most crimes are committed by male offenders and most examinees of polygraph examinations are men. Volunteers who contacted us were allowed in the study if they were aged between 18 and 65 years old, and reported not taking medication for medical or psychiatric illnesses. In addition, we selected participants so that we obtained a sample that

Manipulation checks

Ninety-nine percent of the catch items was named correctly, indicating that the participants indeed paid attention to the pictures. Results from the memory check show that the crime pictures were correctly recognized and remembered. Ninety-eight percent of the crime pictures was correctly classified.

Video mock crime

We included mock crime as between subject factor in the initial analyses. No significant effect was found (F < 1.1). We therefore ignored this variable in further analyses.

Psychophysiological measures

Detection efficiency was

Discussion

The present study examined FPLL as an indicator of concealed information. With regard to our three research questions, our results can be summarized as follows.

First, ROC curve analyses showed that detection efficiency of FPA and PR was significantly above chance, but weak (ROC_a = .60–.65). Despite their weak validity, combining them into FPLL lead to high detection accuracy (ROC_a = .82). These results indicate that FPLL is a more sensitive measure than its components. We also examined the relative

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Cited by (27)

Physiological Measures in the Detection of Deception and Concealed Information
2018, Detecting Concealed Information and Deception: Recent Developments
Attempts to detect deception by means of physiological measurement have evolved over more than 100 years. Combining elaborated interrogation procedures with capturing the bodily responses of the electrodermal, cardiovascular, and pulmonary systems brought forth specific procedures and measurement techniques. Nevertheless, a specific physiological pattern accompanying lying was not found in these measures. Yet, the Concealed Information Test (CIT), which classically uses a multichannel recording of physiological measures mostly related to the autonomic nervous system, proved to differentiate between concealed (e.g., crime-related) knowledge and actually absent knowledge (of an innocent person) with remarkable accuracy. From the very beginning of its application, research questions referred to the diagnostic value and the incremental information of each measure, the specific mental processes reflected in the various measures, and, particularly later with technical development, the exploration of new measures. From the applied perspective, the susceptibility of the CIT to countermeasures, leakage of crime-related information to innocents, the importance of the context in which the CIT is applied, or the influence of memory distortions, were prominent questions. Besides providing a brief overview of detection-of-deception paradigms, this chapter focuses on the CIT with “classic” polygraphic measurement, for which it summarizes the development of research lines until the present.
Effects of goal- and task-oriented motivation in the guilty action test
2013, International Journal of Psychophysiology
Citation Excerpt :
From here on, the term RLL refers to covert respiration back recordings. Finger pulse waveform length (FPWL) responses were suggested as a useful addition to the measures currently employed in the detection of concealed information (Ambach et al., 2012; Elaad and Ben-Shakhar, 2006; Vandenbosch et al., 2009). Finger pulse data were recorded using an Atlas Researches (Israel) piezoelectric plethysmograph positioned around the right thumb.
The present study examined the effectiveness of the Guilty Action Test in detecting critical information from goal-oriented and task-oriented informed innocent examinees. A mock crime procedure was employed and informed innocent participants were either motivated to prove innocence (goal-oriented motivation) or to prove innocence by being cooperative on the test (task-oriented motivation). Half of the participants in each motivation condition were promised course credit reward for successful completion of their mission to prove innocence or to be cooperative (high incentive level). The other half were promised no reward (low incentive level). A fifth group of uninformed innocent participants served for control purposes. Electrodemal, respiration, and cardiovascular measures were used to indicate the motivation effects. Results showed that the combination of goal-oriented instructions and an incentive for success contributed to enhanced responses to the crime-related information. The combination of task-oriented instructions and an incentive for success attenuated these responses. Skin conductance responses were most sensitive to these effects. Theoretical and practical aspects of the results were discussed.
Improved method for calculating the respiratory line length in the Concealed Information Test
2011, International Journal of Psychophysiology
Citation Excerpt :
Although these two methods analyze only the respiration curve after the item onset, the part of the respiratory cycle before the item onset would affect the remaining part of the cycle, which is included for calculating the respiration line length. However, the CIT often uses a rather long inter-stimulus interval (i.e., more than 20 s; for example see Gamer et al., 2008; Vandenbosch et al., 2009; Verschuere et al., 2007). This time is set so that a respiratory (and heart rate) response to a question item recovers to the base level (for the time course of the respiratory response after a question item onset, see Fig. 2 of Matsuda et al., 2009a and Fig. 1 of Matsuda et al., 2009b).
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
2011, International Journal of Psychophysiology
Citation Excerpt :
The Concealed Information Test (CIT) originally called Guilty Knowledge Test by Lykken (1959) is a systematic and standardized test procedure employed to detect hidden knowledge by means of physiological recordings. The relevance and validity of the different physiological measures for the detection of concealed knowledge are still a matter of ongoing research (see Elaad et al., 1992; Elaad and Ben-Shakhar, 2006; Hirota et al., 2003, Vandenbosch et al., 2009). A typical investigation procedure combines a standardized interrogation with the continuous collection of electrodermal activity (EDA), electrocardiogram (ECG), breathing activity, and finger plethysmogram.
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.
Effects of perceived reliability and generalization of crime-related information on detection in the concealed information test
2010, International Journal of Psychophysiology
The accuracy of the Concealed Information Test (CIT) in detecting information concealed by informed innocent participants was assessed under varying levels of probability that the obtained information is related to the crime and is therefore correct. For this purpose, 64 participants were randomly assigned to four experimental conditions that were formed by probability levels that the gathered information is correct and is related to the crime. Either absolutely correct (100% correct), highly correct (80%, correct), highly incorrect (20% correct) or totally incorrect (0%, correct) conditions were created. Response generalization was manipulated by replacing 3 of 6 correct items with related stimuli. The replaced stimuli were related to the correct items either semantically, phonetically, or numerically. Informed innocent participants showed larger electrodermal responses to items with a higher probability of being correct. It was further found that participants elicited stronger responses to correct than to replaced items. Theoretical and practical implications of the present results are discussed.
Event-related brain potentials during the standard autonomic-based concealed information test
2009, International Journal of Psychophysiology
The concealed information test (CIT) has been used to detect information that examinees possess by means of their autonomic responses. However, the central activities related to these autonomic responses remain unclear. In this study, we simultaneously recorded 128-ch event-related potentials (ERPs) and various autonomic responses (heart rate, respiratory rate, respiratory amplitude, cutaneous blood flow, and skin conductance response) to a critical item (i.e., the item that participants memorized) and to non-critical items (i.e., items other than the critical item) using the standard protocol of the autonomic-based CIT. A topographic analysis of variance and a temporal–spatial principal component analysis revealed that the critical item elicited a larger negative potential (N2b, 205–298 ms) at central regions and a larger positive potential (positive slow wave, 502–744 ms) at parieto-occipital regions, compared to the non-critical items. Correlation analysis across 21 participants showed a significant correlation between N2b increase and heart rate deceleration in response to critical items compared to non-critical items, but there were no autonomic correlates of the positive slow wave. The results suggest that at least two brain processes are involved in the autonomic-based CIT: The first is an attentional-orienting process that facilitates the processing of critical items, to which heart rate deceleration was linked, and the second is an additional process after the identification of critical items.

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¹: The first two authors contributed equally to the manuscript.

²: Bruno Verschuere is a postdoctoral fellow of the Research Foundation – Flanders (FWO).

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The validity of finger pulse line length for the detection of concealed information

Abstract

Section snippets

Participants

Manipulation checks

Video mock crime

Psychophysiological measures

Discussion

Int. J. Psychophysiol.

Int. J. Psychophysiol.

Biol. Psychol.

Int. J. Psychophysiol.

Appetite

Effects of repeated examinations on the ability to detect guilt with a polygraphic examination: a laboratory experiment with a real crime

J. Appl. Psychol.

Failure to find evidence of the unitary OR concept with indifferent low-intensity auditory stimuli

Physiol. Psychol.

The effect of “significance” upon indices of Sokolov's orienting response: a new conceptualisation to replace the OR

Physiol. Psychol.

Physiological changes in a reaction-time task: further problems with Sokolov's dimension of stimulus “significance”

Physiol. Psychol.

Standardization within individuals: a simple method to neutralize individual differences in skin conductance

Psychophysiology

A critical review of the control question test

Theories and Applications in the Detection of Deception: A Psychophysiological International Perspective

Psychophysiological detection through the guilty knowledge technique: effects of mental countermeasures

J. Appl. Psychol

The validity of psychophysiological detection of information with the guilty knowledge test: a meta-analytic review

J. Appl. Psychol.

Leakage of relevant information to innocent examinees in the GKT: an attempt to reduce false-positive outcomes by introducing target stimuli

J. Appl. Psychol.

Orienting response reinstatement and dishabituation: effects of substituting, adding and deleting components of nonsignificant stimuli

Psychophysiology

Trial by polygraph: reconsidering the use of the guilty knowledge technique in court

Law Hum. Behav.

Alcohol and the psychophysiological detection of deception

Psychophysiology

Accuracy demonstrations, threat and the detection of deception: cardiovascular, electrodermal and papillary measures

Psychophysiology

Estimating the validity of the guilty knowledge test from simulated experiments: the external validity of mock crime studies

J. Exp. Psychol. Appl.

The objective use of multiple physiological indices in the detection of deception

Psychophysiology

The electrodermal system

Psychophysiological Analyses (PSPHA): a modular script-based program for analyzing psychophysiological data

Behav. Res. Meth.