Plethysmography – Wrongly Testing the Wrong Thing

The below is OCEAN Newsletter Volume 1, Issue 2, Article 5 (Aug. 15, 2019) published by Russell J. Hatton & Daniel A. Wilson from the gulag in Moose Lake Minnesota.

 

Just as with the polygraph, penile plethysmography has grave problems as to its unscientific nature. The lead article as to these problems is the first one below. Excerpts from: Max B. Bernstein, “Supervised Release, Sex Offender Treatment Programs, and Substantive Due Process,” 85 Fordham Law Review 261 (2016, Issue 1, Article 11 ); http:/ /ir.lawnet.fordham.edu/flr/vol85/iss 1 /11 Abstract: p. 261: ” .. . This Note argues that mandated PPG testing should be eliminated as a condition of federal supervised release. The test infringes on a constitutionally protected liberty interest against unwanted bodily intrusions and, as only the Second Circuit has held, any condition of supervised release that infringes on a constitutionally protected right may be mandated only where it is narrowly tailored to serve a compelling government interest. Because there are a number of viable, less intrusive alternatives, PPG testing as it stands today is not narrowly tailored enough to serve a compelling government interest.” Text, p. 266: ” . . . [E]ven sex offenders retain at least some level of humanity, and testing methods should not be unnecessarily intrusive or humiliating. The federal supervised release statute codifies this sentiment by explicitly barring any condition of supervised release that unnecessarily infringes on the liberties of the offender.19 p. 268: “Freund’ s PPG testing is commonly referred to as the ‘volumetric method.’37 Freund’s machine was a glass tube that went over the man’s flaccid penis.

The tube was filled with air and sealed with the ‘ominous-sounding “locknut.”’38 After being ‘strapped in,’ the subject would be shown suggestive pictures or reading material, and as blood rushed to the man’s penis it would enlarge and displace the air in the tube.39 Electric wires attached to the tube measured even slight changes in the air volume inside of the glass, signifying to the clinician that the subject was aroused.40 Levels of arousal could be traced to the volume of air displaced.41 “Bancroft invented what he considered to be a less cumbersome and cheaper PPG testing method that is referred to as the ‘circumferential method.’42 Bancroft’s test used ‘ a mercury strain gauge inside a stretchable band.’43 The band is usually a silicone ring wrapped around the penis.44 The mercury in the band surrounds the flaccid penis and is plugged with electrodes.45 As the penis’s circumference expands, the mercury is thinned out against the ring and increases the resistance, which the electrodes pick up to measure expansion of the penis.46 “The volumetric method is considered to be the more accurate and sensitive of the two, as it can detect even ‘the smallest changes in penis diameter.’ 4 7 The volumetric method, however, is more expensive and cumbersome to administer.48 Thus, the circumferential method is used more frequently.49″Regardless of the method employed. There is a documented lack of standardization in the administration of PPG testing. SO p. 269: ” … There is great variation among operators as to what stimuli they present to their subjects.60 Some offenders are even shown real child pornography.61 A number of treatment centers obtained confiscated visual images from law enforcement; however, this was unsurprisingly met with resistance and is now uncommon.62 Other treatment centers have used photos of nude children who were ‘reared in a nudist environment,’ with written consent from the child’s parents.63
… However, the use of computer-fabricated images of children64 or nonsexual photographs of clothed children65 are becoming more common in the administration of PPG testing.” p. 271: “II. THE SCIENCE BEHIND PPG TESTING “Despite the widespread use of PPG testing as a condition of supervised release, legal scholarship on the test is practically nonexistent. There has been only one in-depth review of PPG testing – a 2004 article in the Temple Political and Civil Rights Law Review written by Jason Odeshoo, which has since become the leading (and only significant) legal scholarship on the PPG.82 Other legal scholars have provided cursory critiques of the test, but have failed to meaningfully engage with the test’s utility or limitations, The same cannot be said, however, of the scientific community.” p. 272: “A. What Does PPG Testing Measure and What Do Its Results Say About the Risk of Reoffense? ” . .. [S]ex offenders will express ‘a preference for these cues or for behaviors motivated by the stronger sexual arousal.’ 86 Because people are more likely to perform behavior that optimizes rewards or personal satisfaction, it follows that men with sexually deviant preferences will act on those preferences.87 [But this is actually a non sequitur.] In short, sex offenders are aroused by deviant acts and are more likely to act on their arousal. ” … [A]ssuming that PPG testing can accurately determine a test subject’s preference for sexually deviant material, what does that tell us about the subject’s risk of acting on that behavior? Or, what can PPG testing tell us about the risk of recidivism?” pp. 272-3: ” I . Can PPG Testing Accurately Measure Sexually Deviant Arousal? “As stated above, the short answer is that PPG testing can measure sexually deviant arousal. However, the test has significant limitations. “PPG testing’s effectiveness rest on the premise that a man’s level of tumescence is an objective measure of his sexual arousal to stimuli. Erectile responses, however, are not based on a stable individual trait, and thus it is hard to directly correlate tumescence with arousal.88 Erectile responses are the result of a number of factors, including arousal, but also the subject’s emotional state, fatigue, intoxication, recency of an orgasm, and other unknown endocrine factors.89 Even the gender of the clinician may affect the subject’s level of tumescence.90 “Moreover, sexual stimulus is actually compound stimuli made up of multiple components.91 For instance, a subject may be presented with sadomasochistic sexual scenes that also include explicit descriptions of foreplay and intercourse.92 If the subject reaches 40 percent of full tumescence, was that a result of the violent depictions, the foreplay, the intercourse, or some combination of all three? That 40 percent may be a result of arousal to the violence. Or it may be a result of the intercourse, which would normally arouse the male to 8 0 percent, but his arousal was partially inhibited due to the violence. Based on the problem illustrated by this hypothetical, PPG test results can be unambiguous only when at least two depictions are shown, when all extraneous elements are similar as possible, and when there is only one key difference.93 “The selection of stimuli has a tremendous impact on the erectile response measures.94 For example, some studies have found that audio stimuli present different and more consistent results than videos,95 while other studies have found that only when the stimuli depict particularly violent scenes can the data be useful.96 Indeed, the selection of stimuli has such a great impact on the erectile response measures that ‘an experimenter could construct stimulus materials for use in a study in which any desired result could be obtained. ’97 “Understanding that the clinician exhibits such a great degree of control over the test makes it troubling that there is practically no standardization in the administration or scoring of PPG testing. 98 PPG testing was originally created as a research tool, not a method of clinical assessment. Thus no manual or standard practices were developed.99 pp. 2 74-5: “The lack of standardization across PPG testing leads to serious questions regarding the procedures of scientific reliability.”

Reliability refers to ‘the extent to which an experiment, test, or measuring procedure yields the same results on repeated trials.’ I 00 ‘ [U]nless a test can be shown to be reliable, there is essentially no point in giving it further consideration.’ I 01 PPG’s lack of reliability comes from a lack of standardization in administering and scoring the test, and the problem of faking. In 1995, a researcher named R.J. Howes conducted a study assessing the reliability of PPG testing and the lack of standardization in the test’s administration. 102 Howes examined forty-eight treatment centers throughout the United States and Canada. I 03 The centers had been administering PPG tests for an average of 5 .5 years. I 04 The clinicians administering the test had been doing so for an average of 3.4 years. 105 Seventy-six percent of the clinicians reported that they had been trained for one week or less, and 18 percent responded that they had never been formally trained to administer the PPG at all. I 06 A former president of A TSA noted that the lack of training was ‘truly appalling.’ I 07 Without training and without standard procedural guidelines, the following aspects of PPG testing vary greatly from center to center:

1) Type of gauge used (mechanical, mercury) and transducer placement
2) Type of stimuli used (audiotapes, slides, videotapes)
3) Content of stimuli used ( differences in models)
4) Duration of stimulus presentation (2 sec to > 4 min.)
5) Length of interstimulus (detumescence) intervals (fixed time vs. return to baseline)
6) Nature of stimulus categories sampled .. .
7) Number of categories and of stimuli used for each category
8) Instructions to subjects (imagine sexual behavior with target vs. no instructions)
9) Whether a warm-up was used and number of assessment sessions
10) Type of recording instrumentation used …
11) Whether calibration was used to correct for any nonlinear characteristics of recording
12) Data sampling rate (every 5 sec. vs. every min.)
13) Whether methods were used to attempt to assess for faking
14) Gender and other characteristics of the evaluator
15) Type of data transformation (z-score vs. a deviance index)
13) Whether methods were used to attempt to assess for faking
16) Characteristics of the laboratory … and
17) Type of sample and setting ( outpatient, prison) .108′

“Howes concluded that such inconsistencies across treatment facilities ‘discredit’ PPG testing and cast serious doubt on its results. 109 “Further, there are numerous documented issues that arise from ‘ faking.’ 110 As both supporters and critics of PPG testing agree, those subjects who wish to trick the PPG will likely be successful. 111 Individuals may fake responses by fantasizing about deviant sexual scenes while being presented with non-deviant stimuli or may try to distract themselves while deviant stimuli are presented.  112 Even tests designed to ensure that the subject is paying attention to the stimuli are not foolproof, as many studies have shown that men can exert control over their erectile response or suppress their response entirely.  113 “Despite the significant limitations of PPG testing, it is still ‘generally considered the most accurate measure of sexual arousal.’  114” p. 275: “One meta-analysis of a number of PPG testing studies could find only two studies in which pedophilic offenders could not be distinguished from other offenders.  120″ p. 276: … Although a number of studies have shown that PPG testing can distinguish rapists from non-rapists, 121 a significant number of researchers suggest that it cannot.  122 Those in the latter explain that a number of studies have resulted in ambiguous results or even severe misclassifications of rapists and non-rapists, and thus the studies that have distinguished between rapists and non-rapists lack reliability and should not be trusted.  123 ” … PPG testing has very limited utility in measuring past offense history for rapists as well.  126 PPG tests were unable to determine subjects’ number of victims or whether violence was used and to what extent violence was used in the commission of the subjects’ rapes.  127″ p. 277: “2. What Do PPG Test Results Say About the Risk of Recidivism? ” … [A] man may be aroused by sexually deviant stimuli, but engage in exclusively non-deviant activity because he is aware of social and penal sanctions that come with acting on his deviant arousal.  138 Such concerns, among others, leave PPG testing’s ability to predict the risk of recidivism largely unsettled.  139 ” … [S]ome studies found that PPG testing has a significant relationship with rates of recidivism, albeit a small one.  141 ” … Other researchers believe the relationship between PPG testing and recidivism risk is usually weak  144 or, further, ‘that predicting who is at risk to commit a sexual crime and who is likely to recidivate cannot be predicted with even a moderate level of confidence.’  145 Due to issues with the standardization of PPG testing, the test’s lack of reliability, and the potential for faking, PPG testing’ s ability to predict the ‘ likelihood of reoffending is beyond the scope of the test’s validity.’  146 p. 278: ” … The lack of standardization across the administration and scoring of the PPG makes any data derived from the procedure ‘ idiosyncratic, unamenable to normative comparisons, if not impossible to interpret from a traditional psychometric perspective.’  148 Moreover, there may be significant biases resulting from studies that exclude data from nonresponders or low responders, an exceedingly common practice among PPG practitioners.  149 The sheer lack of evaluations of the test’s validity regarding the biases associated with the exclusion of non-responders suggests that PPG test results cannot be trusted to predict recidivism.  150. ” … Considering PPG’s validity issues, many researchers believe the test should not be used as a predictor of recidivism, especially when making decisions regarding periods of civil confinement, . . . More ardent critics believe that because PPG testing is susceptible to a high rate of false negatives and false positives, either through faking or failure to interpret the data correctly, it should never be used as a predictor of recidivism.  157″ p. 279: B. PPG’s Limited Utility ” .. . Subjects who fail to produce erectile responses present ‘non-interpretable’ data, even though such failure could be due to a number of factors, including faking or a real lack of sexual arousal to the stimuli.  165 . . . It is non-familial child molesters whose erectile data appear most deviant, but even within that subgroup, ‘ no more than 50 [percent] of those who admit to offending and who have multiple victims display deviant arousal.’ 167 [Thus, what use? You’re damned if you do erect, but disregarded if you don’t! ] p.  281: D. Alternatives to PPG Testing ” … VRT [Visual Reaction Time] testing is premised on the assumption that a man will view an image for longer if he is interested in the type of person or activity displayed in that image.  187 Dr. Gene Abel, a pioneer of VRT testing, used the test to successfully discriminate between child sex offenders and non-offenders as well as to distinguish between child sex offenders and non-child sex offenders.  188 Dr. Abel combined VRT testing with self-reporting questionnaires. Together commonly referred to as ‘the Abel Assessment,’ to achieve results that ‘ speak[] the same language’ as PPG testing.  189p. 291: ” … Subjects who fail to produce erectile responses present ‘non-interpretable’ data, even though such failure could be due to a number of factors, including faking or a real lack of sexual arousal to the stimuli.  165 . . . It is non-familial child molesters whose erectile data appear most deviant, but even within that subgroup, ‘no more than 50 [percent] of those who admit to offending and who have multiple victims display deviant arousal.’ 167 [Thus, what use? You’re damned if you do erect, but disregarded if you don’t!] p. 281: D. Alternatives to PPG Testing” … VRT [Visual Reaction Time] testing is premised on the assumption that a man will view an image for longer if he is interested in the type of person or activity displayed in that image.  187 Dr. Gene Abel, a pioneer of VRT testing, used the test to successfully discriminate between child sex offenders and non-offenders as well as to distinguish between child sex offenders and non-child sex offenders.  188 Dr. Abel combined VRT testing with self-reporting questionnaires. Together commonly referred to as ‘the Abel Assessment,’ to achieve results that ‘ speak[] the same language’ as PPG testing.

“One would expect to find it [the tests] bracing the pages of George Orwell novel … There is a line at which the government must stop. This test crosses it.”

Wrote by deeply troubled, Judge Marsha Berzon of the U.S. 9th Circuit Court of Appeals.

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