Methodological Considerations

Part: 
Four
Chapter: 
3

A number of elements need to be considered in the study of sex offender populations.

  1. Nature of the population evaluated

    The deviant populations most accessible to researchers in the past were incarcerated sex offenders. This category thus constituted the samples described in earlier studies, including the significant pioneering surveys done by Gebhard, et al. (1965) and Goldstein, et al. (1970). There is evidence, however, that data provided by incarcerated offenders tends to vary significantly from non-incarcerated groups (Abel, Becker and Skinner, 1985). The demographic profile of incarcerated offenders, for instance, appears to differ from nonincarcerated groups. For example, Goldstein, et al. (1970) found that while forty-two percent of his control sample has some college education, only twenty-six percent of the rapists, twenty percent and five percent of the male-object and female-object pedophiles, respectively, also had similar educational levels. Gebhard, et al. (1965) similarly found lower educational levels among his sexual offender sample compared to controls. Only thirteen percent of heterosexual child molesters, thirteen percent of homosexual child molesters, and twenty-one percent of rapists had a grade eleven or higher education compared to twenty-one percent of other criminal offenders and fifty-two percent of the control sample. Both these studies examined incarcerated samples.

    Abel (1985), on the other hand, found that among an outpatient sample of 192 child molesters, forty-six percent had at least one year of college, with a quarter of the total sample completing college or having an advanced degree. Marshall's (1985) comparison of eighty-nine outpatient sex offenders with twenty-four control adults showed little difference between the mean IQ's of this group and a comparison control. A mean IQ of 92, 93, 94 and 101 was measured for heterosexual and homosexual child molesters, incest offenders, and rapists, respectively, and 91 for the control sample. It has been estimated that incarceration rates for some sex offenders are low. Only thirteen to sixteen percent of rapists are actually incarcerated, for instance (Abel, Becker and Skinner, 1985; Dietz, 1978), making it likely that an outpatient sample of sex offenders/deviants would more closely resemble the population of deviant cases than an incarcerated one. The representativeness of such an outpatient group still is uncertain, given the fact that these are individuals who, either voluntarily or by court mandate, have sought treatment.

  2. Measurement of Arousal.

    An important aspect of evaluating sexual deviance in terms of diagnosis, treatment, and projection of future behavior has been the assessment of arousal patterns. A major weakness in the early studies on sexual deviance was that measures of arousal consisted solely of self-reports. An extensive review of various assessment procedures (Zuckerman, 1971) concluded that the measurement of penis size (penile tumescence) in response to various stimuli provides the most valid indicator of sexual arousal. While the development of the penile transducer provided more accurate assessments of male arousal, problems still exist with this technology. The primary problem is that it is possible for the offender to control his erectile responses (by controlling his attention and sexual fantasies. See Quinsey and Bergersen, 1976; Laws and Holman, 1978; Abel, Becker and Skinner, 1985; Abel, Rouleau and Cunningham-Rathner, in press). However, it has been possible to identify such faked responses under planned treatment situations and to reduce their occurrence but not to eliminate them entirely (Abel, Mittelman and Becker, 1985).

  3. Ethical Considerations.

    Clinical researchers are obviously unable to examine sex offenders in laboratory conditions to assess cause-andeffect relationships in the same way their social psychologist counterparts are able to do with non-deviant or "normal" populations. The risks are too great for a group with little or no control over their own behaviors. Furthermore, the notion of informed consent becomes a problem when physiological measures of arousal patterns may reveal interest patterns the patient may not even be aware of (see Able, Rouleau and CunninghamRathner, in press). Other ethical considerations further arise out of the occasional conflicting needs of the judicial system, the offender's needs and rights, therapeutic requirements, and even the public interest (see Bohmer, 1983; Abel, Rouleau and Cunningham-Rathner, in press, for an extended discussion).

A number of important advances have been made in the last fifteen years to elucidate the nature of sexual deviancy, particularly as they relate to the measurement of arousal patterns. On the whole, however, certain inherent limitations exist for this particular population that preclude gaining the fullest knowledge about the antecedents of their sexual behaviors. One of the earliest landmark studies based on interviews with sexual offenders was conducted by the Kinsey Institute for Sex Research (Gebhard, et al., 1965). The study was notable for its scope, including 1365 sex offenders, 888 other criminal offenders, and 477 controls, all white males. The study was conducted during two time periods: 1941 to 1945 and 1953-1955.

Interviews with sex offenders led the authors to conclude that no relation between pornography and sex crimes exists. The researchers, in fact, concluded that the inferior intelligence and education of the average sex offender precludes his deriving sufficient sexual arousal from pornography to lead to overt antisocial activity, a conclusion which has been contradicted by much subsequent data.

Some of the other earlier studies on this question were done for the 1970 Commission. On the basis of these early studies (see, for example, Cook and Fosen, 1970; Goldstein, et al., 1970; Walker, 1970; Davis and Braught, 1970), the Commission concluded that (1) sex offenders did not differ from adults in the general population in their reported immediate responses to reading or viewing erotic materials; (2) that sex offenders generally had less adolescent experience with erotica than the general adult population but did not differ from the latter in adult exposure patterns; and (3) erotica was an insignificant factor in the reported likelihood of engaging in sexual behavior during or after exposure.

Since these early studies, much more has been learned about sex offenders in terms of their arousal patterns and efficacies of various treatment approaches.