A research article by Rieger and colleagues (2016) suggests that women are almost never exclusively heterosexual , but that most are aroused by images of both men and attractive women. We will now analyze this study so that the reader can assess the degree of credibility of this bold statement.

The University of Essex study

Recently a research team from the University of Essex led by psychologist and anthropologist Gerulf Rieger has published the results of their studies on the differences between men and women in response to sexual stimuli. These authors also analyzed the peculiarities of these patterns in homosexual people.

The article by Rieger and collaborators is based on two studies carried out by this team. The first of these focused on genital responses associated with sexual arousal and on self-reports on the degree of masculinity or femininity perceived by the subjects in themselves.

The second investigation, however, focused on a particular sign of sexual response: pupil dilation or mydriasis in the presence of sexual stimuli . This element was also compared again with the degree of masculinity/femininity, although in this case it was measured by external observers as well as through self-reporting.

According to the authors of this study, their hypotheses were based on different information obtained in previous research. One aspect that stands out in this regard is the scientific evidence regarding differences in the sexual responses of men and women, as well as those between heterosexual and homosexual women.

Differences in arousal between men and women

Various studies, including the one by Rieger’s team, have found significant differences in reactivity to sexual stimuli depending on biological sex. In particular, the sexual response of heterosexual men is specific to female stimuli , but that of heterosexual women is not so specific to male images.

It seems that the physiological response (in this case pupil dilation) of heterosexual males appears to be almost exclusively when the eliciting stimuli include female elements. This would be the typical pattern in men who consider themselves heterosexual, although the response may vary from case to case.

In contrast, women respond to both male and female sexual stimuli even though they claim to be exclusively heterosexual. Thus, the degree of pupil dilation of heterosexual women proved to be similar when the sexual images presented included men as when they were other women.

This is why Rieger’s team ventures to say that women are not usually completely heterosexual, but that most of them would be bisexual. Specifically, 74% of the heterosexual women who participated in the study showed intense sexually-activated responses to viewing images of attractive women.

Patterns according to sexual orientation

According to researchers at the University of Essex, homosexual women are the exception to the general female pattern . Interestingly, their sexual response seems to be more similar to that of men than to that of women – always bearing in mind, of course, that studies of this type focus on mean values.

Thus, women who claim to be exclusively attracted to women tend to react selectively to female sexual stimuli, rather than when they interact with men. As we can see, this response is closer to that of the male gender than to that of women who consider themselves heterosexual.

In addition, Rieger’s team suggests that the behavior of homosexual women tends to be more typically male than that of heterosexual women. The degree of selectivity in the response to female sexual stimuli seems to be correlated with the intensity of the masculinity of the external behavior (“non-sexual masculinity”).

However, the authors claim that there is no evidence that sexual and non-sexual patterns are connected. Thus, these two types of masculinity would develop independently as a result of different factors, in the words of this research team.

All bisexuals?The cause of these differences

The University of Essex team’s studies used visual sexual material. In this sense, it should be taken into account that, according to research such as that of Hamann et al. (2004), men respond more intensely than women to visual stimuli when these are related to sexuality.

This seems to be related to the fact that certain regions of men’s brains are activated more than those of women in the presence of this kind of image. In particular, some of the relevant structures are the amygdala (especially the left one), the hypothalamus and the ventral striatum, which is located in the basal ganglia.

In contrast, women appear to be more context-driven ; that is, they tend to show responses such as pupil dilation if sexual keys are present in the situation, regardless of whether they are male or female.

It has been proposed that these differences could be due in part to differential socialization between men and women. Thus, while men would learn to suppress homosexual thoughts in times of sexual arousal, women might feel less socially pressured in this regard.

Bibliographic references:

  • Hamann, S., Herman, R. A., Nolan, C. L. & Wallen, K. (2004). Men and women differ in amygdala response to visual sexual stimuli. Nature Neuroscience, 7: 411-416.
  • Rieger, G., Savin-Williams, R. C., Chivers, M. L. & Bailey, J. M. (2016). Journal of Personality and Social Psychology, 111(2): 265-283.