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A series of 4 experiments were conducted to (a) determine the willingness of children to lie in a realistic setting, (b) compare judgments of credibility from both lay evaluations and Criterion-Based Content Analysis (CBCA), and (c) examine the effects of expert testimony regarding Statement Validity Assessment on mock jurors who were asked to make evaluations of the children's statements. In Experiment 1, 81% of children who witnessed a research assistant steal a textbook made accusations against the thief (truthful), 69% of children who did not witness the theft accused the research assistant of the theft following prompting by significant others, and 56% of the children who witnessed a significant other steal the textbook incorrectly accused the research assistant following a request from their significant other. Using the statements obtained from the children in Experiment 1, Experiments 2 and 3 found that classification accuracy of lay evaluators was significantly poorer than expert application of CB...

The volunteer biases present in psychophysiological studies of sexual arousal were investigated in two geographically distinct sites. Four hundred eighty‐five male and female undergraduates at the University of North Dakota and Oklahoma State University completed a packet of questionnaires which included demographics and personality‐ and sexuality‐related measures. Participants were then given an opportunity to participate in a sexual arousal study, for which 74 individuals volunteered. Significant differences were found between males and females on sexual guilt, and between volunteers and nonvol‐unteers on four out of five measures. In addition, analyses of the reasons nonvolunteers provided for not participating suggest that the types of measurement and stimuli often influence what types of individuals volunteer for such research. These results have serious implications for the generalizability of such physiological arousal measures, and indicate a need for the development of less intrusive measures of ...

Short-term and long-term habituation of sexual arousal was investigated in a crossover design. Nine subjects completed six sessions semiweekly for 3 consecutive weeks. Sessions were scheduled at least 2 days but not more than 4 days apart. Each session consisted of 15 stimulus periods and 15 detumescence periods. Sexually explicit audio stimuli were administered. There were two conditions in the crossover design, which allowed each participant to serve as his own control. During one half of the sessions subjects were exposed to 15 different scripts (varied condition); during the remaining sessions subjects were exposed to the same script 45 times (15 trials for each of three sessions, the constant condition). The constant stimulus condition was the experimental habituation condition, whereas the varied stimuli served as a control for physiological fatigue. Scripts were randomly assigned to stimulus conditions. Subjects showed systematic decreases in penile responding within the second and third constant stimulus conditions, but no systematic decreases were noted in any of the varied stimulus conditions. Subjects evidenced significant long-term decreases in physiological responding only in the constant stimulus condition as well as short-term decreases in subjective report of arousal. Long-term habituation of sexual arousal may be related to molar behaviors such as promiscuity and the spread of sexually transmitted diseases, and may be tied to sociobiological accounts of long-term sexual behavior patterns in human males.

The effects of a physical (pressing the toes to the floor) and a mental (counting backward by sevens) countermeasure on the concealed knowledge test (CKT) were examined in a mock crime experiment with 40 subjects. Some knowledgeable subjects were informed about the nature of the CKT and were trained in the use of a countermeasure, whereas others remained uninformed. All subjects were offered a monetary reward if they could produce a truthful outcome. Subjects were tested using standard field techniques and instrumentation. The physical and, to a lesser extent, the mental countermeasures reduced the accuracy of the CKT. These results clearly demonstrate that the CKT has no special immunity to the effects of countermeasures.

The authors examined human numerical evaluation, discriminant analysis, and a bootstrap approach to decision making in the psychophysiological detection of deception with the control question test. The data for these analyses were obtained from the Utah Cooperative Working Group Database and consisted of 100 innocent and 100 guilty subjects of mock crime experiments. They found statistically equivalent performance for the three approaches. However, it should be noted that the human evaluators used in this study were not representative of the average polygraph examiner, and the human evaluation data reported here are likely to have substantially overestimated the accuracy of human numerical evaluation in the field. Taken in that context, the performance of the statistical classifiers should be viewed very favorably. In absolute terms, the bootstrap approach outperformed the other two approaches. As compared to discriminant analysis, the bootstrap has much to recommend it. It avoids the restrictive mathematical assumptions of discriminant analysis, and since it is not tied to any empirical standardization sample, the bootstrap approach is likely to be widely generalizable. The authors conclude that statistical decision making has come of age in the detection of deception and should see universal applications in the field in the near future.