Detection of guilty knowledge in real-life criminal investigations.

The present study provides a first attempt to estimate the validity of the Guilty Knowledge Test (GKT) in real-life criminal investigations. Skin resistance responses in GKT records of 50 innocent and 48 guilty Ss, for whom actual truth was established by confession, were analyzed by two methods. On the basis of an a priori decision rule, 98% of the innocent and 42% of the guilty Ss were correctly classified. Signal detection measures based on various possible decision rules indicated that the distribution of guilty Ss was highly differentiated from the distribution of innocent Ss. An optimal decision rule yielded correct classifications for 94% of the innocent Ss and 65% of the guilty Ss. These results suggest that the GKT could be a useful investigative tool that protects innocent suspects from being falsely classified as guilty. The false-negative identifications were accounted for in terms of the realistic conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Awareness of crime-relevant information and the Guilty Knowledge Test.

The effects of awareness of crime-relevant information on the detection of deception with the Guilty Knowledge Test were examined. Student Ss were assigned to 1 of 3 groups: a guilty group, members of which committed a mock crime; an innocent group aware of details about the crime; or an innocent group unaware of such information. After following instructions, Ss were tested on the polygraph with a 10-item Guilty Knowledge Test and were offered $20 for an innocent test outcome. Skin resistance response scores of guilty Ss lying about crime-relevant information were higher than the scores of innocent informed Ss, whose scores in turn were higher than those of innocent unaware Ss. This replicated findings of an earlier study in which similar procedures were used and supported the view that Ss aware of crime-relevant information can appear less deceptive than Ss lying about crime-relevant information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social psychology and plea bargaining: Applications, methodology, and theory.

Conducted 2 experiments with male undergraduates to investigate the plea bargaining process. Exp I (143 Ss) used a role-playing procedure to identify variables that affect the acceptance of a plea bargain. 18% of the Ss playing the role of innocent defendants accepted the plea bargain, whereas 83% of the guilty defendants accepted. Two other main effects revealed that defendants were more likely to accept a plea bargain when relatively many charges had been filed against them and/or when the severity of punishment upon conviction was great, although internal analyses revealed that these effects were present in guilty defendants only. Exp II (18 Ss) was conducted using involved participants to provide validation for the major result of Exp I. Ss were made to be innocent or guilty of having prior information about an exam. All were accused of having used prior information and were given an opportuinity to plea bargain rather than face an ethics committee. In accord with Exp I, guilty Ss accepted the plea bargain significantly more often than innocent students. Results are discussed in terms of information differences between innocent and guilty defendants and the availability heuristic. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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

To evaluate whether antianxiety drugs enable guilty Ss to appear innocent on polygraph tests, the authors compared the effects of diazepam, meprobamate, and propranolol on the outcome of a guilty knowledge test (GKT). 75 undergraduate students were evenly divided among 1 innocent and 4 guilty groups. Ss in each of the guilty groups received either 1 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 Ss 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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of feedback of physiological information on responses to innocent associations and guilty knowledge.

Investigated the effects of providing Ss with feedback concerning their physiological responding while they were questioned about (a) innocent associations varying in degree of personal involvement and (b) innocent associations vs guilty knowledge. In Exp I, 48 undergraduates were divided into 3 groups—electrodermal, heart-rate, or no feedback. Ss were then questioned separately about a list of geometric figures, containing one that they had chosen beforehand, and about a list of Social Security numbers, which included their own. Results, based on the relative amplitude of electrodermal responses, indicate that feedback significantly augmented responses to the relevant item as did personal involvement. In Exp II, 26 undergraduates were provided with guilty knowledge about a mock crime while another 26 Ss received innocent associations. Half of each group received electrodermal feedback and half no feedback. Results show significant differences in the responding of guilty and innocent Ss. Feedback increased responding to relevant items in both groups. (5 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The GSR in the detection of guilt.

How accurate is a lie detector in determining guilt? "Forty-nine male college students, after random assortment into four groups, were required to enact one, both, or neither of two mock crimes. All were then given a guilty knowledge test, employing the GSR, which used six standard questions relating to each of the two crimes. A simple, objective, and a priori scoring system was used to determine guilt. Forty-four or 89.8% of the Ss were assigned to their correct group, against a chance expectancy of 25%. Considering the crimes separately, all Ss innocent of a crime were correctly classified, while 44 or 50 interrogations of guilty Ss gave guilty classifications, a total of 93.9% correct classification against a chance expectancy of 50%… . Detection of guilty knowledge… is demonstrably capable of very high validity in those situations where it can be used." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do the clothes make the man? An exploration of the effect of lineup attire on eyewitness identification accuracy.

In 3 experiments, 392 undergraduates witnessed staged crimes and attempted to identify criminals from photographic lineups containing a picture of the guilty party or a similar looking but innocent suspect. Lineup attire was manipulated: (1) Only the suspects wore clothing similar to that worn during the crime (biased lineups); (2) everyone wore different attire (usual lineups); and (3) everyone was dressed alike. Data reveal that the rate of identifications of the guilty party was not influenced by lineup attire. However, the innocent suspect was most likely to be identified from a clothing-biased lineup. Data also show that Ss who selected the suspect clothing from photographs of clothing were significantly more accurate in their identification of the person than Ss who failed to select the suspect clothing. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mental and physical countermeasures reduce the accuracy of polygraph tests.

Effects of countermeasures on the control-question polygraph test were examined in an experiment with 120 Ss recruited from the general community. Ss were given polygraph tests by an examiner who used field techniques. 20 Ss were innocent, and of the 100 guilty Ss, 80 were trained in the use of either a physical countermeasure (biting the tongue or pressing the toes to the floor) or a mental countermeasure (counting backward by 7) to be applied while control questions were being presented during their examinations. The mental and physical countermeasures were equally effective: Each enabled approximately 50% of the Ss to defeat the polygraph test. The strongest countermeasure effects were observed in the cardiovascular measures. Moreover, the countermeasures were difficult to detect either instrumentally or through observation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Validity of an expanded-issue (Modified General Question) polygraph technique in a simulated distributed-crime-roles context.

The validity of an expanded-issue control-question technique that is commonly used in investigations was tested with simulations of thief, accomplice, confidant, and innocent crime roles. Field numerical scores and objective measures discriminated between the guilty and innocent groups. Excluding inconclusives (guilty?=?18.1%, innocent?=?20.8%), decisions based on total numerical scores were 84.7% correct for the guilty group and 94.7% correct for the innocent group. There was relatively weaker, but significant, discrimination between the thief group and the other guilty groups and no significant discrimination between the accomplice group and confidant group. Skin conductance, respiration, heart rate, and cardiograph measures contributed most strongly to discrimination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Positions of Truthfully Answered Controls on Control Question Tests With the Polygraph.

Students (N = 120) guilty of a mock crime, innocent and informed, or innocent and uninformed of crime details were examined by polygraph with an altered form of Control Question Test (CQT). Ambiguous, lie-engendering control questions were altered to form clear direct questions answered truthfully. When these control questions were positioned before crime-relevant questions, most guilty and innocent participants were correctly classified. Most participants were classed as guilty when crime-relevant questions were positioned before control questions. Lying to crime-relevant questions in the second position resulted in skin resistance, F(2,108) = 8.2, and blood volume, F(2, 108) = 6.1, responses larger than Orienting Responses to initial control questions. Accurate detection depends on the position of control questions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychophysiological detection through the guilty knowledge technique: Effect of mental countermeasures.

The effects of mental countermeasures on the efficiency of psychophysiological detection with the Guilty Knowledge Technique were examined in a mock-crime experiment with 4 groups of participants: innocent participants who were not involved in the mock crime, guilty controls who committed the mock crime but received no countermeasure instructions, guilty participants who received countermeasure instructions, and guilty participants who received countermeasure instructions and were allowed to practice the countermeasures. The countermeasure instructions encouraged participants to recall emotional situations from their past and imagine themselves in these situations during presentation of irrelevant questions. Results revealed a significant reduction in electrodermal detection efficiency under the 2 countermeasure conditions with no differences between them. No countermeasure effects were observed with the respiration line length measure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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

This study focused on the Guilty Knowledge Test (GKT)—a psychophysiological detection method based on a series of multiple-choice questions, each having one relevant and several neutral (control) alternatives. The study examined a new method designed to reduce false-positive outcomes due to leakage of relevant items to innocent suspects by introducing target items (i.e., items known to all examinees but unrelated to the crime) to which participants have to respond (e.g., by pressing a key) while answering the GKT questions. Informed innocent participants showed relatively larger electrodermal responses to the critical items than uninformed participants, but not as large as the responses made by guilty participants. No differences between informed and uninformed innocent participants were obtained with a respiration measure. The use of the target items tended to reduce the differences between informed and uninformed innocent participants. The results further demonstrated that electrodermal responding to the relevant items was correlated with memory of these items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Procedure and outcome effects on reactions to adjudicated resolution of conflicts of interest.

Examined the effects of outcome on reactions to an adjudication procedure and the effects of procedures on reactions to an adjudication outcome. 111 male undergraduates were led to believe they had been charged with wrongdoing of which they knew they were innocent. The charge was tried, and the Ss outcomes were determined using procedures (adversary or nonadversary) high or low in perceived procedural justice. Ss were then told that they had been found innocent or guilty. Perceptions of the trial process were assessed either before or after the verdict was announced. After the verdict, additional questionnaires assessed perceptions of the verdict and overall perceptions of procedural and distributive fairness. Results show that disputants saw the adversary procedure as fairer than the nonadversary and that they saw the verdict as more fair and satisfying, and as more accurate and unbiased, when it followed an adversary trial. (10 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of task and method of stimulus presentation on the detection of deception.

In a detection of deception experiment comparisons were made of the effects of 2 methods of stimulus presentation and 2 different subject tasks. The relevant-irrelevant method of stimulus presentation proved equally effective for both tasks, but the peak-of-tension method was significantly less effective where the S's task was to deceive as to the nature of guilty information possessed (guilty information paradigm) than it was where the task was to deceive as to the possession of any information (guilty person paradigm). In general, Ss found it easier to deceive in the guilty information paradigm, where they could attempt to "appear guilty" on a noncritical item and especially when they could anticipate the order of presentation of items (peak-of-tension method). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A control question test oriented towards students

Control Question Tests were altered for 12 of 24 students who were examined with a polygraph about a mock crime which half of them had committed. The altered tests substituted control questions about students' cheating and plagiarism for the standard questions about crime issues. Responses to the altered tests were compared with those from tests using regular control questions which are usually about criminal issues. All tests were conducted by a professor. Detection scores derived from response magnitudes of skin resistance differed between innocent (M = 2.0) and guilty participants (M = -1.9). Guilt and innocence interacted with the type of test. Those examined with control questions oriented towards students scored as more innocent when actually innocent (M = 4.3) than guilty students examined with the student form (M = -3.0) or the crime form (M = -0.8) of the test and innocent students (M = -0.3) examined with control questions oriented towards crimes. The discussion is augmented by results from a direct analysis of magnitude of scores.     

Psychopathy, threat, and polygraph test accuracy.

The accuracy of the control question polygraph test with psychopaths was evaluated within a realistically threatening context. Subjects were 24 psychopathic and 24 nonpsychopathic male prison inmates. Within each diagnostic group, equal numbers of "guilty" and "innocent" subjects were tested by experienced professional polygraphers regarding their involvement in a mock theft by using standard control question procedures. A group contingency threat was devised in which subjects believed that their personal performance could decide benefits or penalties for the sample as a whole. Guilty psychopaths were detected just as easily as guilty nonpsychopaths, and the majority of guilty subjects (87%, excluding inconclusives) were correctly identified. However, innocent subjects were identified with only 56% accuracy, and an analysis of false positive errors suggested that the subjective impact of the threat was a critical factor in these outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Truth and deception: A reply to Lykken.

In reply to D. T. Lykken's (see record 1979-30044-001) review of the validity of lie detector tests and his criticisms of the present authors' (see record 1978-07412-001) survey, evidence is presented showing that control question tests of deception have an accuracy of approximately 90% in the field situation and are highly effective with both innocent and guilty Ss. Lykken's representation of the theory of lie detector tests is questioned, and the correct application of control question tests is discussed. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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

18 male undergraduates who scored high on the MMPI Pd scale and 16 who scored low on the Pd scale took a written intelligence test on which they were urged to cheat by confederates posing as other Ss. Approximately 50% of the Ss cheated. The Ss were then given a guilty knowledge polygraphic examination concerning their possible cheating behavior, during which 3 physiological measures (heart rate, finger pulse volume, and skin resistance) were recorded. The examination was given to each S twice. Results indicate that (a) only skin resistance was effective for detecting guilt, thus suggesting that other physiological measures employed by examiners may introduce errors; (b) the procedure was only effective for detecting guilt the first time it was used, thus indicating that repeated examinations may be invalid; and (c) there was no difference in the detection rates for Ss with high or low Pd scores. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unconscious transference and mistake identity: When a witness misidentifies a familiar with innocent person.

Unconscious transference occurs when an eyewitness to a crime misidentifies a familiar but innocent person from a police lineup. In Experiment 1, Ss watched a film of a robbery. Transference Ss saw an innocent bystander in the film, whereas control Ss saw the same film without the innocent bystander. When asked to identify the assailant from a lineup that contained the familiar bystander without the assailant, transference Ss were nearly 3 times more likely to misidentify the bystander than were control Ss. A majority of the transference Ss who misidentified the bystander inferred that the bystander and the assailant were the same person, which reflects what we refer to as conscious inference. In Experiment 2, the unconscious transference effect was eliminated when transference Ss were informed prior to being shown the lineup that the bystander and the assailant were not the same person. Experiments 3 and 4 found that transference Ss inferred that the bystander and the assailant were the same person at the time they first observed the assailant. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An integration theory analysis of jurors' presumptions of guilt or innocence.

An averaging model of information integration was used to (a) identify 4 conceptions of juror fair-mindedness and (b) provide a quantitative solution for determining weights and scale values in functional measurement. 80 male and female college students estimated the likelihood of guilt for 18 different defendants described by stimulus sets that varied with respect to case type, amount of trial evidence, and incrimination value of trial evidence. Data indicate that jurors assumed innocence and that this assumption was averaged with trial evidence to produce the final opinion. An individual-difference measure identified Ss who were pro- and antidefendant; antidefendant Ss judged it more likely the defendant was guilty. This difference was found to result from 2 factors. Surprisingly, antidefendant Ss adopted a more lenient initial disposition than prodefendant Ss. However, the antidefendant Ss more readily abandoned their presumption of innocence when incriminating evidence was presented than did prodefendant Ss. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)