The Research Report entitled
Sexual Arousal Patterns of Bisexual Men by Rieger, Chivers, and Bailey published in Psychological Science noted that self-identified bisexual men in their study did not generally experience strong genital arousal to both male and female sexual stimuli. The paper says "most bisexual men appeared homosexual with respect to genital arousal, although some appeared heterosexual. In contrast, their subjective sexual arousal did conform to a bisexual pattern." These results are interesting and I will take a closer look at them.
They advertised in gay-oriented magazines and an alternative newspaper in Chicago for heterosexual, bisexual, and gay men for a paid study of sexual arousal. It is a tough job to find representative heterosexual men who read gay-oriented magazines or alternative newspapers, I would think. But, in fairness, setting up a good study of sexual arousal is a tough job.
They showed participants in the study an 11-minute sexually neutral and relaxing film, followed by four 2-minute sexual films and then another neutral film. Now personally, a string of 2-minute films would not be very sexually stimulating to me. I tend to need some time to get into my thoughts and a series of two-minute jolts would do little for me. Now two of these sexual clips depicted two men having sex with one another and two showed two women having sex with one another. Finding a way to balance the level of sexual stimulation of these films would be difficult. We cannot make a judgment of how balanced they were because we are told nothing more about them.
But, most American males have ready access to to film clips showing two women having sex with one another, but less ready access or a need for more courage anyway to see films of two men having sex together. This is surely true of heterosexual and bisexual men. So, on the one hand one can see two brief films of a type one has seen many times, while on the other hand, one sees film of two men having sex which one has probably seen less often. The new experience or the less frequent experience is often the more arousing as compared to the routine experience. One would expect that men with relatively little experience watching men have sex with one another will experience at least some degree of heightened arousal due to its relative newness.
The degree of sexual arousal was measured by applying a strain gauge to each participant's penis. If the growth of circumference was less than 2 mm, the data was not used in the genital arousal part of the study. Presumably, this just means that at some point in time while watching the film clips, arousal exceeded 2 mm. The difference was apparently then expressed in terms of the number of standard deviations, since no units of length (i.e. mm) are given and that was the procedure used by Chivers, Rieger, Latty, and Bailey in an earlier article entitled
A Sex Difference in the Specificity of Sexual Arousal.
The final sample consisted of 21 heterosexual men, 22 bisexual men, and 25 homosexual men according to their self-identifications, in which Kinsey scores as multiples of 0.5, from 0 through 1 were considered heterosexual, from 5 through 6 were considered homosexual, and those from 1.5 through 4.5 were considered bisexual. The men were asked to rate themselves on the Kinsey scale for the relative degree of attraction for women and men with a score of 0 meaning attraction only to women and a score of 6 meaning attraction only to men. A score of 3 would presumably mean an equal degree of attraction to each. The study also had the men push a lever forward to indicate arousal and back to indicate less arousal. This measured their subjective arousal.
As the results were presented below, they did not seem to confirm a tendency for bisexual men who identified themselves with Kinsey scores near 3 as having a genital response which was similar for both men and women. Their subjective arousal indicated with the lever was more consistent with a similar stimulative effect by both men and women for bisexual identifiers. The actual arousal is measured versus the Kinsey score in each graph below:
Unfortunately, this is not the data itself, but some sort of apparently hand-drawn fit to the data which is not shown. All across the spectrum of the Kinsey scale, the less arousing sex was still somewhat arousing. One of the more salient results in the genital arousal data is that those men who identified themselves as near or in the homosexual zone of the Kinsey scale were even more polarized in their sexual preference than were the men at the heterosexual end of the scale. Strangely, those in the bisexual range were simply intermediate in this degree of polarization.
There are aspects of these plots which I find hard to understand in light of the individual data points provided in the case of the genital arousal difference, which is the strain gauge genital response to male stimuli minus that of the response to female stimuli. If a man is more aroused by watching two women have sex, the number is negative. If he is more aroused by watching two men have sex together, it is positive. The units are apparently in terms of the standard deviation still. That data is shown here:
Let us use a very simple method to look a little harder at what this data is telling us about genital arousal for men. Let us find a simple average for each Kinsey scale number. There is a caveat I must make here. There are supposed to be 21 heterosexual data points, but I could only distinguish 20, with perhaps some debate on two of those, due to overlapping data points. Of the 22 bisexual men, I could only distinguish 21 data points. While I have 25 data points for the 25 homosexual men, some may be somewhat in error due to overlaps also. But, the effects of these problems are small on the results I will discuss.
Now by looking at the data for local regions of the Kinsey scale self-identification, one sees that the results in the range from 0 through 1 are similar and they average -1.31, showing a considerable genital preference for women in the heterosexual men. But at the other end of the scale, the men with Kinsey scores from 4 through 6 are very similar and average 1.47, indicating a stronger preference for genital arousal by male stimuli than heterosexual men had for arousal by women. Those males who self-rated as 2.5, 3, or 3.5 had similar degrees of preference and they did prefer male stimuli. This preference was substantially weaker than that of the men scoring themselves 4s or more. Finally, the men choosing scores of 1.5 and 2 had a slight preference for women with an average of -0.23.
While the men in the 2.5 to 3.5 range might have been expected to have an average genital arousal differential closer to zero, they certainly are a distinguishable group from those scoring themselves 4 or more, who are quite homosexual judging the genital response alone. It would appear that the men scoring themselves 1.5 and 2 are the men actually more in the mid-range zone one would normally consider bisexual. But, I would note again that this is a study of small numbers of men, chosen by a method that might selectively pick out men more sexually adventurous and even inclined to be interested in same sex stimuli, and that the film clips used for the male-male sex may have been more novel and exciting than those used for the female-female sex stimuli. A reverse novelty effect may explain why two men who rated themselves 6s and one who rated himself a 5.5, were actually more stimulated by the female stimuli than by the male stimuli. For some men who are immersed in homosexual activities regularly, woman on woman sex may sometimes be more novel and exciting.
On the other hand, a great many men only somewhat or occasionally attracted to men are very insistent in seeing themselves as heterosexual. Generally those men more attracted to women than men have every incentive in our society to crowd the low Kinsey numbers and to fear to venture out into higher numbers. A certain bias for men choosing higher Kinsey numbers being more attracted to men than a linear scale would suggest is not surprising. But, it is also not surprising that the men in the 1.5 to 3.5 range distinguish themselves both from heterosexuals and homosexuals based on their genital arousal responses. They do rightly see themselves as different by genital arousal and by subjective arousal as well.
It is highly instructive to look at the distribution of men in each self-rating group with respect to their genital arousal differential measurement. One man with Kinsey score 0 had a genital measurement of about -0.5 indicating a very substantial sexual response to males. One man in the 0.5 Kinsey group had a measured response very near the average of those who rated themselves 1.5 or 2 on the Kinsey scale. One man who self-rated a 1, was slightly more attracted to men genitally. It might be best to ignore the self ratings for a moment and simply look at how many men seem to fall enough in a middle ground by genital response to be considered bisexual. Looking at the data, there are plenty of men measuring near -2 who are quite heterosexual. There are also many measuring near 2 who are quite homosexual. It would seem to be reasonable to consider those who measure between -1 and 1 as bisexual then. They are certainly not as strongly polarized as those men with differential scores near 2 or -2. There are at least 18 such men in the middle ground, which includes 5 who rated themselves 5.5 or 6 on the Kinsey scale and 5 who rated themselves 0, 0.5, or 1 on the Kinsey scale! The remaining 8 genitally bisexual men had rated themselves from 1.5 to 3.5. Substantial genital arousal by the same sex is very commonplace across the entire self-rated Kinsey scale!
Those men who chose Kinsey numbers of 4 and 4.5 might simply be indicating that they are willing to consider having sex with a woman who might arouse them, or that they have at some time been aroused by a woman and they are simply acknowledging that fact. This is a more mental activity choice than a merely genital reaction to some general and anonymous film sexual stimulation. These men may be predominantly homosexual, which their number choice indicates them to be in their self-assessment, but they may also be more aware of the fact that women can offer them some genital and mental sexual stimulation.
We do not well-understand the degree to which we are biochemically predisposed to be attracted by one sex or another and how our minds through our thinking processes and fantasizing come to influence our attractions. It would not be surprising if heterosexual and homosexual men tend to be more biochemically hardwired, while those who are bisexual are less hardwired and more mentally attuned to the attractions of both sexes. They do often say that they respond more to the person's character than to the person's sex. That suggests a higher degree of mental input, which is fully consistent with the subjective arousal response observed in the Bailey study. It may also make sense that the mental response occurs first in some bisexual men and then, with some delay, the genital arousal occurs. The short and choppy film stimuli would not be conducive to a genital response delayed by a mental response. I think we can be sure the 2-minute clips neglected character development and got right down to mechanical sex, so this stimuli should have under-stimulated those bisexual men whose attraction to one sex or other was not adequately addressed by the film clips. This will systematically make some bisexual men appear to be either heterosexual or homosexual. This is most definitely not a random type error.
The investigators of this study seem to alternate between good distinctions and interpretations and clearly wrong interpretations. The abstract seems to state their findings well, but the fourth sentence of the Discussion Section says
On average, both homosexual and heterosexual men had much higher arousal to one sex than to the other, and this was equally true of the bisexual men.
As we saw in the table above, this is not true unless one lumps the homosexual men of Kinsey scores 4 and 4.5 in with the rest of the bisexual men and performs that very gross average. This is a failure to handle the data in a manner consistent with the actual data. One should not let a pre-conceived notion lead one astray when interpreting the data. Just as the genital arousal difference data for men who rated themselves 4 and 4.5 match that of the men who self-rated as 5, 5.5, and 6, so does the subjective arousal difference data. There is no way to distinguish the men rating themselves 4 and higher in this study from one another by any of the measurements made.
Bailey and company conclude by saying:
...our results suggest that male bisexuality is not simply the sum of, or the intermediate between, heterosexual and homosexual orientation. Indeed, with respect to sexual arousal and attraction, it remains to be shown that male bisexuality exists. Thus, future research should also explore nonsexual reasons why some men might prefer a bisexual identity to a homosexual or heterosexual identity.
The first claim that bisexuality may not be either the sum of or the intermediate of heterosexuality or homosexuality, may be true. But, their differential genital arousal does clearly distinguish them from both heterosexuals and homosexuals in the Kinsey range from 1.5 to 3.5. Their subjective responses also distinguish them. Finally, we also note that the number of men with intermediate scale genital contrast scores taken across the entire self-rated Kinsey scale was substantial. This questioning of the very existence of bisexuality is disingenuous. It flies in the face of the results of this study and this expression of doubt became the primary subject of extensive media attention. This study should have concluded that though their participation pool was limited and the stimulating media had shortcomings, the data tends to confirm that bisexual men do exist both on the basis of differential genital arousal and differential subjective arousal. Not only do they exist, but many of them self-rate themselves as either heterosexual or homosexual.
Better studies with larger numbers of participants are needed. The brain arousal scan approach they mention should be used in combination with the genital strain gauge measurements and subjective measurements. The stimuli used need to be examined for their effects on results as well. Do longer film clips with some effort to develop desirable character make a difference? It is important to know whether it makes a difference if one shows bisexual men two women making love, a man and a woman making love, or two men making love. Does it make a difference if the films show people making love or just having mechanical sex?
It also needs to be remembered that general stimuli by people unknown to the respondent does not work well for many people. A man really may experience little arousal for most women or most men, but a great deal of arousal for some particular man or woman. A man may only look at women when walking down the street, yet be very attracted to one of his golf and hunting male friends. Is he not bisexual, even if he only responds then to the film clips of the two women having sex? Or what if he has only had sex with women but he has a specific fantasy based on no particular man but based on a circumstance in which he finds himself with a man and this sexual fantasy is very arousing? Is he not bisexual again even if this circumstance was not presented by the study film clip? One can substitute man and woman in each of these questions as well.
When all is said and done, I do not think the existence of bisexual men will be doubted. But clearly, science knows little about them and this is a great shortcoming in our understanding human sexuality. Meanwhile, it is really bad manners to tell someone who self-identifies as bisexual that he does not exist or that he is simply lying to himself. Before doing such a thing, one ought to know what one is talking about.
This post was revised on 17 September 2011.
