Frequencies of minor physical anomalies

Handedness

A modified version of the Edinburgh Handedness Inventory (EHI; Oldfield, 1971) was administered to assess participants’ hand preference when performing the following activities:

• writing,
• drawing,
• throwing,
• using scissors,
• using a toothbrush,
• using a knife,
• using a spoon,
• striking a match,
• using a broom, and
• opening a box.

The modifications to the original EHI inventory consisted of

• (a) delivering the instructions orally instead of having participants fill out the EHI themselves, and
•  (b) instructing participants to make a binary “left” or “right” decision, instead of indicating a weak or strong preference.

Only the first eight of the 10 aforementioned activities were used to capture hand preference due to poor loading of the last two items (i.e., using a broom and opening a box) on the handedness factor (Fazio & Cantor, 2015). A Laterality Quotient (Oldfield, 1971) was calculated by subtracting “left” responses from “right” responses and then dividing the resulting number by the sum of “left” and “right” responses combined. Thus, lower Laterality Quotient scores corresponded to lower rates of right-handedness.

Data Analyses

The Peripheral Anomaly Index [PAI]  has a potential range of 0 – 2; however, in this sample, participants had either feet or hand anomalies but not both, which represents a de facto dichotomous coding of 0 (absence of peripheral anomalies) or 1 (presence of peripheral anomalies on either feet or hands). Thus, the Peripheral Anomaly Index was treated as a categorical variable.

The remaining metrics — the ADI, the Craniofacial Anomaly Index [CAI] , and the Total Anomaly Score [TAS] — were treated as continuous variables.

In reporting correlation statistics,

• Pearson r was used when both variables were continuous and relatively normally distributed,
• Spearman’s rho was used when ordinal variables were involved,
• point-biserial correlation was used for correlations involving both categorical and continuous variables, and
• the phi coefficient was used when only categorical variables were examined.

In line with Howell’s (2013) assertion that dichotomous variables can be treated as ordinal without affecting the analysis, the relationship between dichotomous and ordinal variables was examined through Spearman’s rho.

Results

The mean MPA score

• for pedophiles was 3.9 (SD = 1.4), as compared with
• 3.6 (SD = 1.6) for hebephiles, and
• 3.4 (SD = 1.4) for teleiophiles.

To serve as the omnibus test of association, set correlation was applied, with zero-order correlations as follow-up tests to identify the source of the omnibus effect. Whereas traditional correlation provides a measure of association between two variables, set correlation provides a measure of association between two groups (i.e., sets) of variables (Cohen, Cohen, West, & Aiken, 2003). This sequential approach comprises the protected t test method of controlling the familywise error rate (Keppel & Wickens, 2004).

For the omnibus set correlation test, the MPA indices were entered as one set (ADI and the Total Anomaly Score) and the indicators of pedophilia were entered as the second set (Phallometric Pedophilia Index, number of child victims, and any admission or charges of child pornography possession).

The Craniofacial Anomaly Index and the Peripheral Anomaly Index were not entered alongside the other MPA indices because the nature of their relationship was expressed as a sum in the Total Anomaly Score and as a ratio in the ADI. The analysis yielded a statistically significant multivariate association, Rao’s F(6, 232) = 2.55, p = .021.

The follow-up analyses revealed that the Phallometric Pedophilia Index was significantly related to ADI, r(123) = .19, p = .019; that is, higher craniofacial-to-peripheral ratio corresponded to greater pedophilic interest (see Table 2). This association appeared attributable to a combination of an increased Craniofacial Anomaly Index, r(123) = .13, p = .084, and a decreased Peripheral Anomaly Index, r pb(123) = ?.14, p = .064. When arithmetically summed to form the Total Anomaly Score, however, the positive and the negative effects of the craniofacial versus peripheral anomalies appeared to cancel, r(123) = .073, p = .21.

Table 2

Similarly, the number of victims age 14 and younger was significantly positively related to ADI, r s(137) = .24, p = .002, and negatively related to the Peripheral Anomaly Index, r s(137) = ?.26, p = .001.

Neither the association of the Craniofacial Anomaly Index, r s(137) = .012, p = .45, nor the Total Anomaly Score, r s(137) = ?.071, p = .20, with the number of child victims, reached statistical significance. The number of adult victims (age 17 and older) was not significantly related to any MPA measure: ADI, r s(137) < .01, p = .49, Craniofacial Anomaly Index, r s(137) = ?.053, p = .27, Peripheral Anomaly Index, r s(137) = .011, p = .45, and Total Anomaly Score, r s(137) = ?.061, p = .24.

As with phallometric scores and child victim counts, admissions to child pornography possession, r s(137) = .26, p = .001, and charges of possession of child pornography, r s(137) = .24, p = .003, both related to higher ADI scores.

Admissions to child pornography possession, ?(137) = ?.22, p = .005, and charges of child pornography possession, ?(137) = ?.20, p = .008, both related significantly negatively to the Peripheral Anomaly Index.

There were also positive associations between the Craniofacial Anomaly Index and both child pornography possession, r s(137) = .12, p = .089, and child pornography charges, r s(137) = .12, p = .074. The relationships between the Total Anomaly Score, and child pornography possession, r s(137) = .015, p = .43, or child pornography charges, r s(137) = .025 p = .39, were not significant.

Ancillary Analysis: Are MPA Scores Related to Non-right-handedness?

Although not statistically significant, an elevated ADI corresponded to lower rates of right-handedness (i.e., lower Laterality Quotient), r s(119) = ?.076, p = .21. Further, a higher Craniofacial Anomaly Index was significantly related to lower rates of right-handedness, r s(119) = ?.17, p = .032. There was also an association between an elevated Total Anomaly Score and lower rates of right-handedness, r s(119) = ?.13, p = .085. The relationship between the Peripheral Anomaly Index and the Laterality Quotient did not reach statistical significance, however, a higher Peripheral Anomaly Index appeared related to higher rates of right-handedness, r pb(119) = .055, p = .302.

Discussion

The current investigation examined the prevalence and distribution of MPAs within a clinical sample of men referred for sexological assessment. Cross-study comparisons regarding MPA rates are complicated by the heterogeneity of test items and scoring methods used

• (e.g., Extended 41-item Waldrop in Ismail et al., 1998; Modified 19-item Waldrop in Sivkov & Akabaliev, 2003; 15-item Waldrop in Hata, Iida, Iwasaka, Negoro, & Kishimoto, 2003; dichotomous scoring versus weighting; total score versus mean score etc.).

Green et al. (1989), one of the few studies whose use of the Waldrop Scale was comparable to the present investigation, reported a mean MPA score of 1.81 (SD = 1.63) in the male schizophrenia group and a mean of .74 (SD = .82) in the male control group.

By comparison, the mean MPA score obtained by the pedophiles in the current sample suggested they possess relatively more MPAs than are found in both schizophrenic and non-clinical samples.

Unlike the Green et al. (1989) study, which used a group of healthy participants as controls, the present investigation could not produce a direct comparison of MPA rates between pedophiles and healthy controls because the teleiophilic group was primarily composed of males who had sexually offended against adults. Moreover, although the mean score of the pedophilic group was comparatively elevated, so were the mean scores of the hebephilic and teleiophilic groups. Subsequent research should include both pedophiles and healthy controls in order to ascertain the extent to which pedophiles manifest more MPAs than healthy controls.

MPA indices were associated with multiple indicators of pedophilia, including

• phallometric responses,
• number of child but not adult victims, and
• admission or charges of child pornography possession.

Specifically, greater pedophilic interest corresponded to an elevated craniofacial-to-peripheral ratio.

Along those lines, manifesting greater pedophilic interest was to a lesser extent related to more craniofacial anomalies and fewer peripheral anomalies.

This pattern of results is understandable given that the craniofacial-to-peripheral ratio was composed of an increased number of craniofacial anomalies and a fewer than typical number of peripheral anomalies. The craniofacial and peripheral anomalies canceled each other out when the Total Anomaly Score was used, but were even more observable when expressed as a contrast ratio.

Although this field of research is still in its infancy, there is some indication that several neurodevelopmental disorders (e.g., schizophrenia [Compton et al., 2011], Fetal Alcohol Syndrome [Jones, 1997], etc.) that are accompanied by craniofacial anomalies do not appear to show the craniofacial-peripheral distinction evident in pedophilia.

The craniofacial-peripheral distinction emerged regardless of how pedophilia was assessed. Namely, sexually offending against children was related to a higher craniofacial-to-peripheral anomalies ratio.

Further, offending sexually against children was associated with fewer peripheral anomalies.

Finally, participants charged with possession of child pornography had an elevated ratio of craniofacial-to-peripheral anomalies and showed a trend towards having more craniofacial anomalies, but they generally manifested fewer peripheral malformations. An identical pattern was observed among participants who self-disclosed (but were not charged with) child pornography possession. Given the very strong association between child pornography possession and pedophilia (Seto, Cantor, & Blanchard, 2006), the cumulative effect of these findings implies that more craniofacial anomalies and fewer peripheral anomalies were substantially more frequent among males erotically attracted to children.

Given the current findings regarding the prevalence of craniofacial anomalies among pedophiles, the relationship between MPAs and non-right-handedness was explored, the latter marker having been previously linked to pedophilia (Cantor et al., 2004, 2005b; Fazio, Lykins, & Cantor, 2014). Consistent with the pattern of results described thus far, more craniofacial anomalies corresponded to higher rates of non-right-handedness.

A guiding motive for examining MPAs was their prenatal origin. In particular, the parallel development of brain tissue and morphologic abnormalities (Compton et al., 2007; Green et al., 1989; Lane et al., 1997) appears indicative of a neurodevelopmental contribution to pedophilia, with the stage of craniofacial development emerging as particularly crucial. That craniofacial malformations are also present in other neurodevelopmental disorders, such as

• schizophrenia
  (Compton et al., 2011; Gourion et al., 2004; Lane et al., 1997; Waddington, Lane, Larkin, & O’Callaghan, 1999),
• Down syndrome, and
• Fetal Alcohol Syndrome (Jones, 1997),

further suggests a neurodevelopmental basis of pedophilia. Relatedly, it is conceivable that these neurodevelopmental disorders and pedophilia may be different manifestations of a common underlying (and as yet unidentified) process.

A growing body of evidence regarding the prenatal antecedents of pedophilia has been steadily accumulating over the past few years. Prior work examining rates of non-right-handedness among pedophiles has similarly suggested a prenatal component based on the premise that handedness is a result of mostly prenatal development and therefore rarely results from postnatal life events (Cantor et al., 2004, 2005b).

Aside from serving as a prenatal correlate of pedophilia, handedness can also isolate a critical period during embryogenesis that may be especially sensitive to the prenatal development of pedophilia.

Specifically, studies examining the earliest development of lateralized behavior, and in particular handedness

• (Hepper et al., 1998; Hepper, Wells, & Lynch, 2005; McCartney & Hepper, 1999), found that isolated arm movements were observable at 10 weeks of gestation (corresponding to the first trimester).

This in utero hand preference persists into adulthood; Hepper et al. (2005) concluded that, despite minor shifts in hand preference among left-handed children, prenatal thumb sucking at 15 weeks predicted postnatal handedness (measured by the modified EHI) at 10–12-years-old. Given its relationship to handedness, it is reasonable to hypothesize that pedophilia may be developing prenatally and concurrently with handedness.

Whereas handedness anchors the differences between pedophiles and non-pedophiles as existing by week 10 of gestation, MPAs suggest that these differences may occur at an even earlier period during fetal development. Ear malformations occur as early as weeks 3–5 of embryogenesis (Miller et al., 2005). Therefore, the elevation of craniofacial malformations among pedophiles suggests that pedophiles may differ from teleiophiles by the 5th week of gestation.

A related question here is how MPA development may relate to pedophilia. Although the exact mechanism remains elusive, there is some indication from clinical case studies that hypoxic events (e.g., ischemia, edema from hemorrhage, cocaine exposure, etc.) during the early embryonic period may determine the extent and nature of malformations (Miller et al., 2005).

In particular,

• CHARGE syndrome
  (typically involving
  • colobomas [missing pieces of tissue from the eye],
  • heart defects,
  • choanal atresia [blockage of the nasal airway],
  • retarded growth and/or development,
  • genital anomalies, and ear anomalies and/or hearing loss),
• and early (but not later) thalidomide embryopathy

are both characterized by ear anomalies (craniofacial) in the absence of limb defects (peripheral), therefore resembling the pattern of anomalies in pedophilia, and have been hypothesized to be related to hypoxic/vascular events (Miller et al., 2005).

Limitations and Future Directions

The marginally significant but consistently negative association between peripheral anomalies and indicators of pedophilia suggests two potential interpretations that should be targets of future research.

• One interpretation is that pedophiles are less susceptible to peripheral anomalies, perhaps because of some overcompensation that happens during development.

• Another interpretation is that there is something atypical in the control sample (i.e., teleiophiles), perhaps because the comparison group employed here possessed more antisocial features and/or is more prone to peripheral anomalies.

Subsequent studies would need to compare pedophiles simultaneously with multiple control groups, including a healthy control group.

A final interpretive concern is whether MPAs can be specific to a particular disorder or condition.

Despite the consistently elevated MPA rates found among individuals diagnosed with schizophrenia, Compton and Walker (2009) argue that, relative to developmental disorders, MPAs are not unique to schizophrenia. Compared with other complex mental health conditions, however, the prevalence of elevated MPA rates in schizophrenia, especially craniofacial insults

• (Compton et al., 2011; Gourion et al., 2004; Lane et al., 1997; Waddington et al., 1999),

is, to some degree, specific to this disorder

• (Compton & Walker, 2009; Compton et al., 2011; Green et al., 1994).

That elevated MPA rates, particularly craniofacial anomalies, were also found among pedophiles in the current investigation suggests a non-negligible neurodevelopmental contribution.

Acknowledgments

This research was supported by Canadian Institutes of Health Research Grants 79276 and 89719 to James M. Cantor.

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