Sexually Arousing: The Penile Plethysmograph

In Czechoslovakia during the 1950s, Kurt Freund developed the penile plethysmograph (PPG) to stop drafters from falsifying that they were homosexuals to evade military service. The PPG is a device that gauges blood course within the penis when being exposed to image stimuli. This tool determines the intensity of sexual arousal while the subject is subjected to sexually evocative photos, movies, or audio. When the PPG was first invented, it used pornographic photos to illicit a response; however, nowadays it is more common to use non-pornographic stimuli in order to “[shift] the focus to the general arousal patterns rather than a specific arousal point” (Penile Plethysmograph). Over time, the PPG has found many uses such as screening in regards to erectile dysfunction, psychological experiments, law enforcement, and could possibly become a reliable technique for finding individuals with pedophilia potential.

Of the many purposes of the PPG, one is in screening organic versus psychogenic erectile dysfunction (Penile Plethysmograph). Virilplant defines erectile dysfunction as “the inability of the male to obtain and or maintain penile erection sufficient for…penetration.” According to WebMeds, “it is estimated that 10 to 20 million men suffer [from] erectile dysfunction in the United States. Erectile dysfunction can generally be categorized as organic or psychological. Organic dysfunction means that the problem lies within physiology—whereas psychological erectile dysfunction means that the body is functioning normal but the mind is hindering normal function whether it is due to anxiety or depression. While both are classified as erectile dysfunction, the causes for the sexual disorder are polar opposite. The PPG, by bombarding the affected with images, are related to the mind, and which are related to the body by how much blood enters the penis, if images illicit a sexual response, how long the engorgement lasts, and whether fetishes or sexual orientation are the cause of their inability to maintain an erection. Since the treatment is completely different depending on which cause for the disorder one possesses, the PPG is an important tool to doctors and psychologists.

Another function of Penile Plethysmography is in psychological experiments. For the most part when using classical conditioning, the behavioral psychologist can see or measure the results of his or her conditioning through response. For example, when Skinner conditioned a child to fear a white rabbit, the response was seen: fear. When Pavlov conditioned a dog to salivate at the sound of a bell, the response was able to be measured through a device attached to the dog’s mouth. In regards to sexual conditioning, there was no way to gauge or precisely measure what was conditioned. In a recent experiment, subjects were conditioned to demonstrate sexual arousal in reaction to images of shoes. This was accomplished by presenting images of the shoes which were preceded by photos of naked women. With the invention of the PPG, it is now possible for psychologists to expand their methods of measuring and data collection. Instead of utilizing a survey or Likert scale, measurements can now be taken that are not as biased or subjective which opens a new door to the future of Psychology.

Also, the PPG is utilized in law enforcement. Wikipedia makes the distinction that “the PPG is not intended to be used as a guilt or innocence tool, but rather as a supplemental device to add to a complete psychosexual evaluation” (Penile Plethysmograph). There are two major methods to gage erectile responses. One can measure the volume changes in the penis or one can monitor differences in penile circumference. Measuring penile circumference is the most accepted practice in the psychiatric/psychological communities. When using the PPG, “the gauge is fitted around the penis after being examined to ensure proper functioning” (ForensicEvidence.com). Then, when the device is in place, a baseline level of arousal is determined. Visual and Auditory stimuli are presented and the increase in circumference is recorded. The first time the PPG caught attention from the public was in December 2003 with the trial of basketball star Kobe Bryant (CNN.com). Kobe Bryant was charged with sexual assault and the state of Colorado would require evaluations with the PPG following Bryant’s conviction (Penile Plethysmograph). So, law enforcement has found use in the PPG in finding progress after conviction to gauge progress in therapy and mindset.

And now with the uprising of pedophiles selecting jobs in the churches, school districts, and after school activities in the community, the PPG would be a great screening technique. Using the John Jay Report, it was found that accusations were raised against a total of 4,392 priests between the years 1950 and 2002 (John Jay Report). This statistic does not include the many other accused pedophiles found in school districts and after school activities. Ultimately “penile plethysmography is a test utilized to make subjective determinations about an individual's psychological condition with regard to certain sexual disorders and deviant behavior in the male” which would make an accurate device for screening potential pedophilia. This device has “been used in many states when evaluating convicted sex offenders” (Penile Plethysmograph) so why not require it for those who seek jobs relating to children. In regards to biases with the test toward males, “[an] equivalent procedure for women, vaginal photoplethysmography, measures blood through the walls of the vagina, which researchers claim increases during sexual arousal” (Penile Plethysmograph). A PPG is a biological lie detector, and while tests are not 100% foolproof, the institution of the PPG would bring about a decrease in child molestation within communities.

However, there are still some flaws to be worked out in the test before it could be concrete enough to be considered valid to restrict certain people that fail the PPG in relation to jobs dealing with to children. Before the test could be implemented there would have to be standardization for the test. As of today, those giving the test can choose their own pictures and audio stimuli for the specific cases. There would have to be a devised set of stimuli that would be a constant for all test takers. Also critics argue that some can control their arousal levels, however, the PPG is so precise that it can detect arousal that even the patient can not detect. These two kinks are being dealt with now, so screening for potential pedophiles is somewhere in the near future.

The major issue in making the penile plethysmograph screening a reality is the right to privacy in the United States. A person has a right to keep their sexual orientation and preferences out of the view of the public. However, homosexuality and heterosexuality are not against the law whereas pedophilia is. For example, if there is probable cause that one is under the influences of drugs or alcohol, police have the right to perform tests to prove or disprove their inclinations. Also, if one is found guilty of having alcohol or drugs in their system, the law can require random drug screenings which is not considered invasion of privacy in the eyes of the law. Testing with the PPG would be a precaution for further observation. Pedophilia is an action—and if a teacher does not act on their sexual urges, there would be no need to remove the teacher, coach, or Boy Scout leader from his position. Random screenings would be the result of the PPG and more caution toward certain individuals that are prone to pedophilia. Another example is the person that is told they have a genetic trait that makes them more susceptible to obesity. Close monitoring and outside help prevents the possibility of obesity. If a doctor screened a male for pedophile-like tendencies, then treatment such as behavioral therapy could be instituted at an early stage to monitor behavior and make sure children are not being harmed. The penile plethysmograph has come a long way from being a primitive, non-reliable device that has the potential to change the world. Maybe it won’t take center stage during our life-time, but the possibility is out there.