Orienting to guilty knowledge

The Guilty Knowledge Test (GKT; Lykken, 1959) assesses whether suspects conceal information about a crime ( “guilty knowledge”). Previous studies have demonstrated larger physiological reactions to guilty knowledge compared to unknown information. In three experiments, we investigated whether guilty knowledge also demands attention. During an alleged polygraph examination, participants were presented with to‐be‐detected pictures ( “guilty knowledge”), nonsignificant, familiar pictures ( “mere knowledge”), and previously unseen pictures ( “neutral information”) for 250 ms in a modified dot probe task. In all three experiments, probe responses were slower on guilty knowledge trials as compared to the neutral trials. Results are discussed in terms of an information‐processing view on orienting to guilty knowledge.     

An interfering dot-probe task facilitates the detection of mock crime memory in a reaction time (RT)-based concealed information test

The present study aimed to test the hypothesis that an interfering task in the concealed information test will help the detection of concealed memory based on participants' behavioral performance (e.g. reaction time, error rate). Here, after participants enacted a mock crime, they were introduced to a concealed information test either with or without an interfering dot-probe task. Results showed that the RT-based pure-CIT (without interference) can detect concealed memory well above chance (AUC = .88). The detection efficiency was higher (AUC = .94) in the interference-CIT based on participants' performance of the interfering task. The findings suggested that the elevation of cognitive workload could possibly increase the detection efficiency of concealed memory based on behavioral measures.     

Use of antianxiety drugs as countermeasures in the detection of guilty knowledge.

To evaluate whether antianxiety drugs enable guilty subjects to appear innocent on polygraph tests, we compared the effects of diazepam, meprobamate, and propranolol on the outcome of a guilty knowledge test (GKT). Seventy-five undergraduate students were evenly divided among one innocent and four guilty groups. Subjects in each of the guilty groups received either one of the drugs or a placebo prior to the administration of the GKT and after viewing a videotape that depicted a burglary as seen from the perspective of the burglar. The results showed that drug status had no influence on the outcome of the GKT. Innocent subjects who coincidentally obtained high scores on a recognition memory test covering details of the mock crime tended to obtain higher guilt scores on the GKT.     

Effects of time pressure on strategy selection and strategy execution in forced choice tests

We examined the effects of cognitive load on the strategy selection in the forced choice test (FCT) when used to detect hidden crime knowledge. Examinees (N = 120) with and without concealed knowledge from a mock crime were subjected to an FCT either under standard circumstances or cognitive load. Cognitive load was implemented through time pressure. The FCT distinguished examinees with concealed knowledge from those without better than chance in both conditions, but the counterstrategies did not differ between conditions. Further investigation revealed that time pressure did affect examinees' ability to follow their intended counterstrategy to produce randomized test patterns, which constitutes an effective counterstrategy in the FCT. Hence, time pressure lowered the success rate of effective counterstrategies, but not their incident rates. Further disambiguation of various cognitive load manipulations and their effects on strategy selection and execution is needed.     

The role of motivation to avoid detection in reaction time-based concealed information detection

Do motivated liars lie more successfully? The motivational effort hypothesis predicts that higher motivation effectively diminishes the chance of being detected, whereas the motivational impairment hypothesis predicts that the higher the motivation to go undetected, the greater the chance of being detected. We manipulated motivation in two online reaction time-based Concealed Information Test studies in which participants tried to hide their identity. Detection of concealed identity information in Experiment 1 (n = 259) was successful and a small financial incentive to avoid detection did not impact upon validity. Despite a greater financial incentive and a manipulation check showing that motivation was increased, Experiment 2 (n = 233) did not impact upon the test's validity either. A financial incentive to avoid detection did not decrease the validity of concealed information detection.     

The Role of Guessing and Verbal Response Type in Psychophysiological Detection of Concealed Information

I used a card test to study the effect of guessing on psychophysiological responsivity. Results indicated that subjects who were aware of the card they chose were more responsive to the relevant card than subjects without knowledge of the card they were asked to guess. Psychophysiological responsivity to the guessed cards was greater than to the neutral cards and to chance expectancy. In a verbal response type effect, the combination of the verbal response (yes or no) and the act of lying (no) increased differential responsivity compared with silence. I found no interaction effect between the knowledge of concealed information and the type of verbal response.     

Why (some) Americans believe in the lie detector while others believe in the guilty knowledge test

The accuracy of polygraphic lie detection in real life applications is very little better than chance. Yet, at least in the United States, many agencies and the polygraphers themselves have great faith in the technique. The reasons why polygraph examiners, and their clients, genuinely believe in the myth of the polygraph are explained and illustrated. A more plausible method of polygraphic interrogation, the Guilty Knowledge Test (GKT), is described and it is shown how the GKT, but not the lie test, might have resolved doubts about the case of Demjanjuk, the alleged "Ivan the Terrible."     

The effect of knowledge of mathematics on gambling behaviours and erroneous perceptions

This study evaluates the effect of knowledge of mathematics as a protective factor against excessive gambling behaviours and erroneous beliefs. Two groups with different levels of knowledge of mathematics were compared as to their perceptions and behaviours before and during a gambling session. A total of 60 participants (30 men, 30 women) completed a questionnaire evaluating how they perceive the notion of chance and participated in two experimental tasks: the production of a random sequence of heads/tails, and a gambling session on a video lottery terminal. The results show that participants with knowledge of mathematics held more erroneous perceptions of gambling before the experiment whereas both groups showed an equal number of erroneous perceptions and behaviours during gambling. The importance of knowledge of mathematics as a protective factor against excessive gambling is questionable. The theoretical and practical implications of these results are discussed with regard to the prevention of excessive gambling.     

The revealing glance: Eye gaze behavior to concealed information

We explored the usefulness of eye fixation durations as a dependent measure in a concealed knowledge test, drawing on Ryan, Hannula, and Cohen (2007), who found eye fixations on a familiar face to be longer than fixations on an unknown face. However, in their study, participants always had to select the known face out of three faces; thus, recognition and response intention could not be differentiated. In the experimental phase of our experiment, participants saw six faces per trial and had to select one of them. We had three conditions: In the first, one of the six faces was a known face, and the participants had to conceal that knowledge and select another face (concealed display); in another, one of the six faces was a known face, and the participants had to select that face (revealed display); or finally, all six faces were unknown, and participants had to select any of the six faces (neutral display). Using fixation durations as the dependent measure, we found a pure and early recognition effect; that is, fixations on the concealed faces (known but not selected) were longer than fixations on the nonselected unknown target faces in the neutral display. In addition, we found a response intention effect; that is, fixation durations on the selected known faces were longer than those on concealed faces (known but not selected).     

Memory instructions, vocalization, mock crimes, and concealed information tests with a polygraph

Accuracy rates with polygraphs using concealed information tests (CITs) depend on memory for crime details. Some participants read instructions on murdering a dummy victim that specified exact crime details asked on the subsequent CIT. Others read instructions not stating details, but still requiring interaction with the exact same details for the crime. For example, the murder weapon was under four heavy boxes. Instructions stated either "... remove the 4 boxes ..." or "... remove the boxes ..." Thus, each group removed four boxes, but only one group was primed with the number "4" beforehand. In addition, the victim unexpectedly shouted at some participants during the crime. An innocent group was not exposed to either manipulation. Memory, detection scores, and detection rates were lower for guilty participants not primed with details. Sound affected detection scores but not memory, and there was no interaction between the two factors. Information tests are limited by how crime information is received.     

The Challenge of the Concealed Knowledge Polygraph Test

This paper introduces the concealed knowledge polygraph test (CKT) and suggests that it might be useful for the criminal justice system. The main point is that the CKT is a standard and objective psychological test that can to some extent protect the innocent from false allegation. A review of 15 mock crime studies of the CKT supports this contention. It revealed average detection rates of 80.6% for guilty examinees and 95.9% for the innocent. Furthermore, in 11 of these studies no false positive identifications (i.e. failures to exonerate innocent suspects) were observed. Two field studies revealed similar results, with false-positive error rates that are not larger than expected by chance. However, in the field studies, the detection rates for guilty suspects were substantially lower than those obtained in the 15 experimental studies. Suggestions for enhancing the detection rate of guilty suspects in real life settings are provided.Finally, the effects of several possible countermeasures, such as the use of drugs, biofeedback training and behavioural countermeasure maneouvres, are discussed. It seems that drugs and biofeedback are not effective in the CKT. However, at least the electrodermal measure is vulnerable to the effects of behavioural countermeasures. Possible ways to deal with the problem are discussed.     

Two modes of confidence rating: An effect of episodic information of participant's own past responses in a repeated-question paradigm

Abstract: General knowledge questions with two answer alternatives were employed in experimental session 1; in session 2, the same questions were presented together with participants' own session-1 responses. In order to examine whether or not the episodic information of participant's own responses would suppress standard confidence-rating mode in session 2, rates of answer- and confidence-changes between sessions were analyzed. In session 2, participants were able to change the confidence value to another, if they thought the initial value inadequate. They then had a chance to change the answer to the other and rated their confidence in the new answer. The major results were as follows: (a) Between-session answer change rate was very low; (b) Between-session answer change rate was not a monotonic decreasing function of confidence; (c) However, the rate depended on confidence change from session 1 to before-answer-change rating. These results clearly contrasted with a previous study ( Saito, 1998 ) in which episodic information of participant's own session 1 answers and confidence values was not presented. It was argued that the episodic information triggered another mode of confidence rating or a decision inertia effect.     

Behavioral inhibition and electrodermal activity during deception

We tested the assumption that the act of inhibiting ongoing behavior requires physiological work. In a guilty knowledge test (GKT) paradigm, subjects were induced to attempt to deceive the experimenter on two separate occasions while electrodermal activity was measured. For 20 of the 30 subjects, overt behaviors (changes in eye movement and facial expression) were recorded during the second GKT. Results indicated that the incidence of behaviors decreased during their deceptive responses. This behavioral inhibition coincided with increases in skin conductance level. In addition to suggesting nonverbal correlates of deception, the results indicate that long-term behavioral inhibition may be a factor in psychosomatic disease.     

The repressor personality and avoidant information processing: A dichotic listening study

The present research was designed to investigate the proposition that repressors, operationally defined by the conjunction of low anxiety and high defensiveness, are particularly adept at avoiding the processing of information when motivated to do so. Four groups of participants (nondefensive-low anxious, high anxious, repressors, and defensive-high anxious) were administered a dichotic listening task involving neutral or negative affective words presented in the unattended ear. Participants shadowed the material presented to the attended ear and simultaneously responded to a probe task presented on a video monitor. Results revealed that repressors made significantly fewer shadowing errors than high anxious and defensive-high anxious participants and marginally significantly fewer shadowing errors than low anxious participants for both neutral and negative words. High anxious participants, however, were later able to recognize the negative words that had been presented to the unattended ear at well above chance levels, whereas the recognition memory of repressors for such negative unattended words was at chance levels. In addition, repressors' responses to a postexperiment questionnaire indicated a significantly greater number of distracting thoughts during the experiment relative to other participants. Repressors, it seems, are indeed skillful at avoidant information processing and this capacity may well be related to the emotional memory deficits they have displayed in previous research.     

Detecting concealed information with reaction times: Validity and comparison with the polygraph

The Concealed Information Test is used to assess recognition of information that the examinee cannot or does not want to reveal. Physiological measures recorded with the polygraph have shown to be highly valid measures of concealed information. Research suggests that a reaction‐time (RT) based test may also successfully reveal concealed information. Due to its simplicity, an RT‐based test has great advantages for applied testing. In the present study, we assessed the validity of the RT‐based test for concealed information detection, and compared its discriminative power with the polygraph. Thirty two participants in a feigned amnesia study were promised a financial reward when successfully concealing autobiographical information. Participants performed an RT‐based test, and a polygraph test. The data support the validity of the RT‐based test for concealed information detection, and indicate its discriminative power is similar to the polygraph. Our data confirm the potential of the RT‐based test. Copyright © 2009 John Wiley & Sons, Ltd.     

Information underpinning anticipation of goal-directed throwing

We identified the information used to anticipate throw direction in handball. In two experiments, we examined how anticipation performance is affected when the information from one of five body areas (right arm, shoulders, hips, trunk, or total throw side) was either neutralized or decoupled from the motion of other body segments. In the first experiment, performance was significantly reduced when information from the throwing arm was neutralized, irrespective of skill levels. Skilled participants were negatively affected when the shoulders, hips, and trunk were neutralized, whereas less-skilled participants showed trends toward improvement under identical conditions. In the second experiment, partially disrupting relative motion via decoupling was not enough to reduce the anticipation performance among skilled participants to chance levels, whereas less-skilled participants lost their ability to anticipate in three conditions. Our findings suggest that skilled and less-skilled participants employ different information extraction strategies, yet information from the throwing arm is critical to anticipation for both groups. The two experiments suggest that relative motion mediated by both the absolute displacement trajectories of individual marker locations and their relative timings are important in informing anticipation, irrespective of skill level.     

What are you hiding? Initial validation of the reaction time-based searching concealed information test

The reaction time-based concealed information test (RT-CIT) has been used to judge the veracity of an examinees claim to be naïve by using RTs to test for recognition of relevant details. Here, we explore the validity of the RT-CIT to generate new knowledge about the incident—the searching CIT. In a mock terrorism study (n = 60) the RT-CIT not only allowed to link suspects to known crime details, but also allowed to reveal new crime details well above chance. A simulation study confirms the potential of the searching RT-CIT and identifies conditions under which it performs best. We used an archival dataset that met these conditions (high CIT effect, large number of item repetitions), and found better item classification performance than in the mock terrorism study. The searching RT-CIT could be a new, promising investigative tool to reveal new (e.g., crime) details to the investigative party.     

Exploring the lived experiences of infertility treatment and care by involuntarily childless women

This study explored the lived experiences of fertility treatment and care by South African women with infertility. A total of 21 women from different age and ethnic groups (age range = 26 to 41; whites = 53%, coloured = 47%) were interviewed for the study. The women responded to semi-structured interviews on their lived experiences of fertility treatment and care whilst undergoing treatment. The data were analysed using thematic analysis. Four main themes were identified in the study; including: lack of compassionate care from treatment care providers, the need for infertility clinics to integrate psychosocial support care, a need for continuing education for fertility staff, as well as financial support resourcing. Participants expressed a need for health care staff at fertility clinics to be more attentive to their emotional and psychological needs. In addition, participants perceived a need for psychosocial care as a result of the distressing nature of the treatment process. The women also felt that some health care staff lacked technical knowledge about the fertility treatments and this left them deprived of crucial information. The costly nature of fertility treatment presented as an added burden for participants. Overall, participants seemed to require a more individualised and patient centred form of fertility care.     

Content in Context Improves Deception Detection Accuracy

Past research has shown that people are only slightly better than chance at distinguishing truths from lies. Higher accuracy rates, however, are possible when contextual knowledge is used to judge the veracity of situated message content. The utility of content in context was shown in a series of experiments with students (N = 26, 45, 51, 25, 127) and experts (N = 66). Across studies, average accuracy was 75% in the content in context groups compared with 57% in the controls. These results demonstrate the importance of situating judges within a meaningful context and have important implications for deception theory.     

Skin conductance as an indicator of anticipated concealed knowledge

The present study investigated the effects of anticipation on skin conductance while participants were answering a set of questions which included one of concealed knowledge. Two experiments were conducted. In Exp. 1, 26 participants completed one experimental session. Each participant was asked to choose one two-digit number from 10 to 99 and was presented 19 other randomly generated two-digit numbers. The list of numbers was then presented to the participant on a computer screen, with a 60-sec. interval occurring every two questions. The participant-selected number was defined as the target question which was randomly placed within the 4th to 17th item of 20 questions stated as follows: "Is your selected number?" The participant was asked to answer "No" to all questions. The skin-conductance response to each question was measured. In Exp. 2, the experimental procedure was the same as that in Exp. 1 except each participant first answered 10 nontarget questions, then answered a target question with the participant's selected number, and then answered another 10 nontarget questions. There were a total of 21 questions. Analysis indicated participants in both experiments generated the highest mean skin conductance while answering the target questions, followed by lower amplitudes to questions prior to and after the target question. The skin-conductance response pattern can be used to identify the psychological process of anticipation of concealed information.