ERECTION
// October 25th, 2010 // No Comments » // Impotence
Men acquire erections by fantasy or when confronted with erotic stimuli (psychogenic erections), after direct stimulation of their genitals (reflex erections), and spontaneously during sleep (nocturnal erections).
Psychogenic erections occur in response to any one of a variety of sensory stimuli, usually visual or auditory. Visual and auditory cues are so reliably consistent in provoking psychogenic erections that behavioral therapists often use them to learn more about what stimulates or inhibits erections in normal and sexually dysfunctional men.
All such studies share a traditional experimental “stimulus-response” design. The stimulus is either an audio- or videotape describing or showing heterosexual sex acts. The response is an erection, which is recorded by attaching a sensor, somewhat like a blood pressure cuff, to the volunteer’s penis. The device measures changes in penis size and can be used to determine what conditions enhance or inhibit erection. A normally potent man exposed to an erotic audio- or videotape will develop an erection. When, for example, the content of the audiotape is held constant but the subject is distracted and asked to complete an innocuous questionnaire, he loses his erection. Similarly, if the videotape is replaced by a neutral travelogue, the subject loses his erection.
This stimulus-response model has provided some predictable as well as some unexpected insights into the interaction between psychologic influences and physical responses. The observation that for heterosexual men, an audiotape narrated by a female is more effective in provoking an erection than a similar script narrated by a male is not surprising. Less intuitive is the observation that although mildly threatening cues result in diminution of the erection, more aggressive cues paradoxically enhance arousal.
