Archives of Sexual Behavior, Vol. 5, No. 3, 1976
Autonomic Responses of Transsexual and Homosexual Males to Erotic Film Sequences Ron Barr, M.D., 1,3 and Alex Blaszczynski, B.A.2
Penile volume and galvanic skin responses to nude female and male film sequences were studied in 40 transsexual patients, 44 patients requesting treatment for homosexual impulses, and 60 heterosexual students. Student controls and homosexuals showed significantly greater galvanic skin responses to the preferred than to the nonpreferred sex. Transsexuals tended to show larger galvanic skin responses to females than did male homosexuals. No strong relationships were found between penile volume and galvanic skin responses to the preferred sex. It is concluded that transsexual patients differ significantly from homosexual patients in autonomic responsivity, which may have diagnostic usefulness. KEY WORDS: transsexual; homosexual; penile response; galvanic skin response.
INTRODUCTION The aim of the study was to determine whether transsexual and homosexual males differ in their autonomic responses to erotic film sequences. In a pilot study, 24 transsexuals differed significantly from homosexuals in their penile and galvanic skin responses to erotic film sequences (Barr, 1973). The present study was of 40 transsexuals, including the 24 previously reported. Freund (1963, 1967) described a method of determining the sexual orientation of male subjects by recording penile volume changes while slides of female and male nudes were shown. McConaghy (1967) described a simpler method of measuring penile volume responses. He found that homosexual and heterosexual males differed significantly in their penile volume responses to female and male film sequences; this finding was replicated by Barr and McConaghy (1971). I Senior Lecturer in Psychiatry, University of New South Wales, Australia. 2P~ince Henry Hospital, New South Wales, Australia. 3Address reprint requests to Dr. Ron Barx, School of Psychiatry, Prince Henry Hospital, Little Bay, N.S.W. 2036, Australia. 211 © 1 9 7 6 P l e n u m P u b l i s h i n g C o r p o r a t i o n , 2 2 7 West 1 7 t h S t r e e t , N e w Y o r k , N . Y . 1 0 0 1 1 . N o part of this publication m a y be reproduced, stored in a r e t r i e v a l s y s t e m , or transmitted, in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, w i t h o u t written permission of the publisher.
212
Barr and Blaszczynsld
Davis and Buchwald (1957) studied galvanic skin responses to slides of female nudes, cartoons, landscapes, horror scenes, and geometrical abstractions. Male subjects showed larger galvanic skin responses to female nudes than to the other categories of slide. Female subjects did not show significantly larger galvanic skin responses to female nudes than to the nonsexual slides. Loiselle and Mollenauer (1965) examined the galvanic skin responses of female students to pictures of female and male nudes. Their galvanic skin responses to nude male figures were significantly greater than those to nude female figures. Bancroft and Mathews (1971) studied the autonomic correlates of penile erection in ten normal males. Changes in penile volume and levels of heart rate, forearm blood flow, and skin conductance in response to slides of nude females and neutral scenes were measured. Penile volume changes alone showed significant differences in response to sexual and neutral stimuli. Bancroft and Mathews found that penile volume increases to erotic stimuli were not consistently related to other autonomic responses across subjects. Two of the ten subjects showed significant positive correlations between penile volume increase and skin conductance. In the present study, penile volume changes and galvanic skin responses to erotic stimuli were measured in transsexual, homosexual, and heterosexual males.
SUBJECTS
Forty male transsexual patients were examined (mean age 26.1 years, SD = 6.6). The transsexual patients had presented requesting "sex-change" surgery; all gave a history of cross-dressing, and 33 were dressed as women at initial interview. Thirty-two were taking estrogens regularly. These patients were transsexual in the sense that they had a "strongly held conviction that their sexual identity is misrepresented by their anatomy" (Roth and Ball, 1964). The majority said that their desire for feminine identity began before puberty. None of the transsexual patients experienced sexual arousal while cross-dressing, but one middleaged subject remembered experiencing sexual excitement while wearing women's clothes during adolescence. Forty-four male patients who had presented for treatment of homosexual impulses were studied (mean age 29.0 years, SD = 9.7). None gave a history of cross-dressing. Legal action was instrumental in six of the homosexual patients' being referred for treatment; these six were awaiting trial or were on probation, but stated that they wished to have treatment for reasons other than the legal action against them. Twenty patients had had heterosexual intercourse, and seven were married. Of the 44 patients, 39 gave a history of overt homosexual activity; the remaining five reported no homosexual activity but were distressed by feelings of sexual interest in other males. Sixty heterosexual male first-year university student volunteers were also evaluated (mean age 19.4 years, SD = 2.4).
Autonomic Responses of Transsexual and Homosexual Males to Erotic Films
213
METHOD
The method used for measuring penile volume change was as described by McConaghy (1967). The blind end of a fingerstaU was cut off and the uncut end was stretched over the open end of a cylindrical tin. This was connected by a tube to a standard Grass pressure transducer. The penis was inserted into the tin through the open end of the fingerstall, which maintained an airtight connection. All penile volume changes were converted to correspond to a sensitivity setting of 2 mV/cm on the Grass preamplifier. Galvanic skin responses were measured with a model 5P1 preamplifier in a standard Grass model 5D polygraph. Beckman silver electrodes were placed on the palm of the left hand at the base of the index and fifth fingers. Galvanic skin responses were measured in units of change in the square root of conductance. The subject viewed erotic stimuli while the Grass 5D polygraph recorded changes in penile volume, skin resistance, heart rate, and the time of presentation of stimuli. The erotic stimuli were ten female sequences alternating with'ten male sequences presented at intervals of 1 min. The female and male sequences were of nude or partially clothed young adults and lasted 10 sec. These stimuli SKIN
~lt
RESISTANCE
PENILE
VOLUME
HEART
RATE
H IIIIJIIIII/Illl IlltlJl i lllll IJIll Illll Illll I tliilllllttllllllll Jllllltllillllltl Illi/lllllh I IIIlllltllllll|lllh IIIJlllUlJJlllltll/llllll II II IIII IIilllJlllJJllllllJllh Ill I I I i it |1 iiill[ll i ill i Ill lilY|Illlit IIIIlllltllll l llltlllll l llnlllllllll l llllllll Ill I l[ lllllll111111t111IIItll IIIIIInnltllll|]111 l ll;iHn 1l llllllll[llll Ill i llnnllllllnlllllllllllll!
0
9
A
Fig. 1. Polygraph record showing responses of a heterosexual control to a female and male film sequence.
214
Bart and Blaszczynski
were set into a travelogue film of London. Figure 1 shows the penile and galvanic skin responses of a heterosexual control to a female and male film sequence. The penile volume response was scored by noting the difference between the volume recorded at the time of the nude sequence onset and the time of nude sequence offset. The statistical significance of the difference between the ten responses to females and ten responses to males was calculated using the Mann-Whitney test (Siegel, 1956). The U score obtained with this test reflects the tendency for penile volume increases in response to females to be greater than those in response to males. The maximum heterosexual score is 100 and the maximum homosexual score is 0. Scores of 77 and above and 23 and below are significant at the 0.05 level in the heterosexual and homosexual directions, respectively. Galvanic skin responses were scored by noting the difference between conductance at the time of nude sequence onset and the maximum increase in conductance occurring within the following 10 sec.
RESULTS Sexual Orientation and Penile Volume Responses to Nude Sequences The mean U score for the 40 transsexual patients was 18.9 (SD = 26.0). Thirty-one of the transsexual patients (78%) obtained scores of 23 or lower, in the significantly homosexual range. The mean U score of the 44 patients presenting for treatment of homosexual impulses was 31.9 (SD = 31.0). The difference between the mean U scores of the transsexual and homosexual patients was statistically significant (p < 0.05). The mean U score for the 60 student controls was 90.1 (SD = 16.3). Of the students, 54 (90%) obtained scores of 77 and above, in the significantly heterosexual range. The remaining six students (10%) obtained scores of less than 77 but more than 23. No student obtained a score in the significantly homosexual range. The difference between the mean U scores of the student and homosexual groups was statistically significant (so < 0.001). The mean total penile response to the ten male sequences was +6.96 units (SD = 8.69) for the transsexual patients and +14.6 units (SD = 30.3) for the homosexual patients. The tendency for homosexuals to show larger penile volume increases to male sequences than did transsexual patients did not reach statistical significance. The mean total response of the student controls to female sequences was +23.3 units (SD = 31.8). Student controls showed significantly larger penile volume increases in response to females than did transsexuals to males (p < 0.05). In the homosexual patients, the tendency to show smaller penile increases to males than did student controls to females was not statistically significant.
Autonomic Responses of Transsexual and Homosexual Males to Erotic Films
215
All three subject groups tended to respond to the nonpreferred sex with decreases in penile volume. Among student controls the mean total response to males was - 4 . 9 units (SD = 8.0). Forty-three of the 60 controls (72%) showed a negative total response to males. Transsexuals responded to female sequences with a mean total response of - 4 . 4 units (SD = 8.7). Thirty-two of the 40 transsexuals (80%) showed a negative total response to females. Thus the penile responses of controls and transsexuals to the nonpreferred sex were similar. By contrast, the homosexual patients as a group responded to the nonpreferred sex with penile volume changes which did not differ significantly from 0 (mean +1.72 units, SD ; 11.3). Twenty-five of the 44 homosexuals (57%) showed a negative total penile response to females and the remainder showed a positive response. The tendency for transsexual patients to show penile volume decreases in respense to females more frequently than did homosexual patients was statistically significant (X2 = 5.16, df = 1, p < 0.025). Among the transsexual patients, there was a nonsignificant tendency for those taking high doses of stilbestrol to have low U scores. The correlation between daily stilbestrol dosage (or equivalent stilbestrol dosage of other estrogen) and U score was -0.294 (df = 38, N.S.). The correlation between daily stilbestrol intake and total response to male sequences was -0.057 (df = 38, N.S.). For all three groups of subjects, the relationship between age and total penile response to the preferred sex film sequences was as follows: transsexuals r = -0.416, p < 0.01 ; homosexuals r = -0.259, N.S.; student controls r = -0.142, N.S.
dE" C
in
MICROMHOS
0-300 U) Z
-
.......
Response
to
Females
Response
to
Males
8
9
OOo.,oo o. o 0. u) w
z
.....
~C U~ 0
Z
,< .3
Autonomic Responses of Transsexual and Homosexual Males to Erotic Film Sequences Ron Barr, M.D., 1,3 and Alex Blaszczynski, B.A.2
Penile volume and galvanic skin responses to nude female and male film sequences were studied in 40 transsexual patients, 44 patients requesting treatment for homosexual impulses, and 60 heterosexual students. Student controls and homosexuals showed significantly greater galvanic skin responses to the preferred than to the nonpreferred sex. Transsexuals tended to show larger galvanic skin responses to females than did male homosexuals. No strong relationships were found between penile volume and galvanic skin responses to the preferred sex. It is concluded that transsexual patients differ significantly from homosexual patients in autonomic responsivity, which may have diagnostic usefulness. KEY WORDS: transsexual; homosexual; penile response; galvanic skin response.
INTRODUCTION The aim of the study was to determine whether transsexual and homosexual males differ in their autonomic responses to erotic film sequences. In a pilot study, 24 transsexuals differed significantly from homosexuals in their penile and galvanic skin responses to erotic film sequences (Barr, 1973). The present study was of 40 transsexuals, including the 24 previously reported. Freund (1963, 1967) described a method of determining the sexual orientation of male subjects by recording penile volume changes while slides of female and male nudes were shown. McConaghy (1967) described a simpler method of measuring penile volume responses. He found that homosexual and heterosexual males differed significantly in their penile volume responses to female and male film sequences; this finding was replicated by Barr and McConaghy (1971). I Senior Lecturer in Psychiatry, University of New South Wales, Australia. 2P~ince Henry Hospital, New South Wales, Australia. 3Address reprint requests to Dr. Ron Barx, School of Psychiatry, Prince Henry Hospital, Little Bay, N.S.W. 2036, Australia. 211 © 1 9 7 6 P l e n u m P u b l i s h i n g C o r p o r a t i o n , 2 2 7 West 1 7 t h S t r e e t , N e w Y o r k , N . Y . 1 0 0 1 1 . N o part of this publication m a y be reproduced, stored in a r e t r i e v a l s y s t e m , or transmitted, in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, w i t h o u t written permission of the publisher.
212
Barr and Blaszczynsld
Davis and Buchwald (1957) studied galvanic skin responses to slides of female nudes, cartoons, landscapes, horror scenes, and geometrical abstractions. Male subjects showed larger galvanic skin responses to female nudes than to the other categories of slide. Female subjects did not show significantly larger galvanic skin responses to female nudes than to the nonsexual slides. Loiselle and Mollenauer (1965) examined the galvanic skin responses of female students to pictures of female and male nudes. Their galvanic skin responses to nude male figures were significantly greater than those to nude female figures. Bancroft and Mathews (1971) studied the autonomic correlates of penile erection in ten normal males. Changes in penile volume and levels of heart rate, forearm blood flow, and skin conductance in response to slides of nude females and neutral scenes were measured. Penile volume changes alone showed significant differences in response to sexual and neutral stimuli. Bancroft and Mathews found that penile volume increases to erotic stimuli were not consistently related to other autonomic responses across subjects. Two of the ten subjects showed significant positive correlations between penile volume increase and skin conductance. In the present study, penile volume changes and galvanic skin responses to erotic stimuli were measured in transsexual, homosexual, and heterosexual males.
SUBJECTS
Forty male transsexual patients were examined (mean age 26.1 years, SD = 6.6). The transsexual patients had presented requesting "sex-change" surgery; all gave a history of cross-dressing, and 33 were dressed as women at initial interview. Thirty-two were taking estrogens regularly. These patients were transsexual in the sense that they had a "strongly held conviction that their sexual identity is misrepresented by their anatomy" (Roth and Ball, 1964). The majority said that their desire for feminine identity began before puberty. None of the transsexual patients experienced sexual arousal while cross-dressing, but one middleaged subject remembered experiencing sexual excitement while wearing women's clothes during adolescence. Forty-four male patients who had presented for treatment of homosexual impulses were studied (mean age 29.0 years, SD = 9.7). None gave a history of cross-dressing. Legal action was instrumental in six of the homosexual patients' being referred for treatment; these six were awaiting trial or were on probation, but stated that they wished to have treatment for reasons other than the legal action against them. Twenty patients had had heterosexual intercourse, and seven were married. Of the 44 patients, 39 gave a history of overt homosexual activity; the remaining five reported no homosexual activity but were distressed by feelings of sexual interest in other males. Sixty heterosexual male first-year university student volunteers were also evaluated (mean age 19.4 years, SD = 2.4).
Autonomic Responses of Transsexual and Homosexual Males to Erotic Films
213
METHOD
The method used for measuring penile volume change was as described by McConaghy (1967). The blind end of a fingerstaU was cut off and the uncut end was stretched over the open end of a cylindrical tin. This was connected by a tube to a standard Grass pressure transducer. The penis was inserted into the tin through the open end of the fingerstall, which maintained an airtight connection. All penile volume changes were converted to correspond to a sensitivity setting of 2 mV/cm on the Grass preamplifier. Galvanic skin responses were measured with a model 5P1 preamplifier in a standard Grass model 5D polygraph. Beckman silver electrodes were placed on the palm of the left hand at the base of the index and fifth fingers. Galvanic skin responses were measured in units of change in the square root of conductance. The subject viewed erotic stimuli while the Grass 5D polygraph recorded changes in penile volume, skin resistance, heart rate, and the time of presentation of stimuli. The erotic stimuli were ten female sequences alternating with'ten male sequences presented at intervals of 1 min. The female and male sequences were of nude or partially clothed young adults and lasted 10 sec. These stimuli SKIN
~lt
RESISTANCE
PENILE
VOLUME
HEART
RATE
H IIIIJIIIII/Illl IlltlJl i lllll IJIll Illll Illll I tliilllllttllllllll Jllllltllillllltl Illi/lllllh I IIIlllltllllll|lllh IIIJlllUlJJlllltll/llllll II II IIII IIilllJlllJJllllllJllh Ill I I I i it |1 iiill[ll i ill i Ill lilY|Illlit IIIIlllltllll l llltlllll l llnlllllllll l llllllll Ill I l[ lllllll111111t111IIItll IIIIIInnltllll|]111 l ll;iHn 1l llllllll[llll Ill i llnnllllllnlllllllllllll!
0
9
A
Fig. 1. Polygraph record showing responses of a heterosexual control to a female and male film sequence.
214
Bart and Blaszczynski
were set into a travelogue film of London. Figure 1 shows the penile and galvanic skin responses of a heterosexual control to a female and male film sequence. The penile volume response was scored by noting the difference between the volume recorded at the time of the nude sequence onset and the time of nude sequence offset. The statistical significance of the difference between the ten responses to females and ten responses to males was calculated using the Mann-Whitney test (Siegel, 1956). The U score obtained with this test reflects the tendency for penile volume increases in response to females to be greater than those in response to males. The maximum heterosexual score is 100 and the maximum homosexual score is 0. Scores of 77 and above and 23 and below are significant at the 0.05 level in the heterosexual and homosexual directions, respectively. Galvanic skin responses were scored by noting the difference between conductance at the time of nude sequence onset and the maximum increase in conductance occurring within the following 10 sec.
RESULTS Sexual Orientation and Penile Volume Responses to Nude Sequences The mean U score for the 40 transsexual patients was 18.9 (SD = 26.0). Thirty-one of the transsexual patients (78%) obtained scores of 23 or lower, in the significantly homosexual range. The mean U score of the 44 patients presenting for treatment of homosexual impulses was 31.9 (SD = 31.0). The difference between the mean U scores of the transsexual and homosexual patients was statistically significant (p < 0.05). The mean U score for the 60 student controls was 90.1 (SD = 16.3). Of the students, 54 (90%) obtained scores of 77 and above, in the significantly heterosexual range. The remaining six students (10%) obtained scores of less than 77 but more than 23. No student obtained a score in the significantly homosexual range. The difference between the mean U scores of the student and homosexual groups was statistically significant (so < 0.001). The mean total penile response to the ten male sequences was +6.96 units (SD = 8.69) for the transsexual patients and +14.6 units (SD = 30.3) for the homosexual patients. The tendency for homosexuals to show larger penile volume increases to male sequences than did transsexual patients did not reach statistical significance. The mean total response of the student controls to female sequences was +23.3 units (SD = 31.8). Student controls showed significantly larger penile volume increases in response to females than did transsexuals to males (p < 0.05). In the homosexual patients, the tendency to show smaller penile increases to males than did student controls to females was not statistically significant.
Autonomic Responses of Transsexual and Homosexual Males to Erotic Films
215
All three subject groups tended to respond to the nonpreferred sex with decreases in penile volume. Among student controls the mean total response to males was - 4 . 9 units (SD = 8.0). Forty-three of the 60 controls (72%) showed a negative total response to males. Transsexuals responded to female sequences with a mean total response of - 4 . 4 units (SD = 8.7). Thirty-two of the 40 transsexuals (80%) showed a negative total response to females. Thus the penile responses of controls and transsexuals to the nonpreferred sex were similar. By contrast, the homosexual patients as a group responded to the nonpreferred sex with penile volume changes which did not differ significantly from 0 (mean +1.72 units, SD ; 11.3). Twenty-five of the 44 homosexuals (57%) showed a negative total penile response to females and the remainder showed a positive response. The tendency for transsexual patients to show penile volume decreases in respense to females more frequently than did homosexual patients was statistically significant (X2 = 5.16, df = 1, p < 0.025). Among the transsexual patients, there was a nonsignificant tendency for those taking high doses of stilbestrol to have low U scores. The correlation between daily stilbestrol dosage (or equivalent stilbestrol dosage of other estrogen) and U score was -0.294 (df = 38, N.S.). The correlation between daily stilbestrol intake and total response to male sequences was -0.057 (df = 38, N.S.). For all three groups of subjects, the relationship between age and total penile response to the preferred sex film sequences was as follows: transsexuals r = -0.416, p < 0.01 ; homosexuals r = -0.259, N.S.; student controls r = -0.142, N.S.
dE" C
in
MICROMHOS
0-300 U) Z
-
.......
Response
to
Females
Response
to
Males
8
9
OOo.,oo o. o 0. u) w
z
.....
~C U~ 0
Z
,< .3
