How Sexual Desire Works- The Enigmatic Urge

by Frederick Toates

  A contribution towards the loss of sexual desire in the elderly who are in long-term relationships is thought to be satiation with the familiar after extensive repetition of the same situation and loss of the anticipation of sexual variety (Kinsey et al., 1948). This is in addition to any bodily changes that accompany the ageing process. Change can often revive a satiated desire.

  The intensity of desire felt for a regular partner can decline over time, although the person would ideally wish to maintain a high level of desire. This change does not simply depend upon increasing age, so what does it depend upon? Consider the following:

  When you’ve been married for awhile, let’s face it – sex just isn’t that exciting anymore. It’s all so predictable. Even when we try to be ‘spontaneous’ it’s almost comical because I can predict his every move.

  (Heterosexual woman, age 48 years; Meston and Buss, 2009, p. 133)

  Sims and Meana (2010) asked women who had lost desire for their husbands to explain why they thought that this had happened. The predominant reasons given were (p. 364):

  institutionalization of the relationship, over-familiarity with one’s partner, and the de-sexualization of roles in their relationship.

  In other words, sex had become predictable and habitual, done largely out of a sense of duty. Fatigue, household chores and the presence of children at home were commonly given as reasons for declining desire. Another factor that emerged was ‘lack of transgression in married life’. The earlier ingredient of risk and uncertainty had been removed, except that associated with children intruding into the bedroom, hardly an aphrodisiac! Consider how this was expressed by women in the study:

  There is no longer that first kiss or that first touch. I think that’s why a lot of people cheat.

  (34-year-old woman)

  Now it’s the same guy and there is no novelty anymore.

  (33-year-old woman)

  The authors wrote (p. 376):

  The results of this study question the extent to which women’s sexual desire depends on commitment, closeness, and intimacy. These relational qualities may be necessary for some women’s desire, but our results indicate that they are hardly sufficient for others. Many of the women in our sample bemoaned the company and security of marriage as anaphrodisiacs.

  Some women gave loss of romance as a reason for the decline in desire, even though they all reported happy marriages. However, the romance related to a time when they had first met their husbands, presumably when novelty and uncertainty were at their height. The authors suggest that women’s sexual desire is something much more heterogeneous than was hitherto thought to be the case. Although all the women studied would be described by some as suffering from ‘hypoactive desire disorder’, this needs qualification. Many said that a change of partner would rekindle their flagging desire. Hence, a unitary expression such as ‘sexual drive’ as some purely internal factor divorced from social context would obviously be misleading. The authors suggest the possible value of finding an optimal location on a scale between, at one extreme, no commitment and, at the other, such commitment as leads to total predictability and boredom.

  Sims and Meana (2010, p. 378) conclude:

  revisions to a reductionist view of women’s sexual desire as a pure drive, divorced from its relational context, were long overdue. It is important, however, to remain mindful to not overcorrect and assume that women’s sexual desire is exclusively contingent on intimacy and loving committed relationships.

  Ways of achieving novelty

  A large family circle

  According to family circumstances, there might be little need to venture beyond the home to find sexual novelty. This is exemplified by the Biblical King Solomon, who presumably would have experienced minimal problems with boredom: ‘And he had seven hundred wives, princesses, and three hundred concubines’ (1 Kings 11:3).

  Desire outside the established bond

  Flirting by people already in an established pair-bond makes good functional sense even though it can come with some risks (Buss, 2005). By showing interest, a person is in a sense playing safe (cultivating a ‘back-up’) in that the target of the gesture sees a possible future partner. This could come in handy if the established bond is broken as in bereavement or being abandoned.

  Married women tend to seek affairs at times of marital disharmony, whereas men in even happy relationships tend more often than women to seek affairs (Buss, 2003). This fits ideas on the greater interaction of attachment and sexual desire in women as compared to men (Chapter 15).

  A survey in Holland showed that, when a person’s power increased, as exemplified by the bosses of multinational companies, so did their tendency to commit adultery and their wish to do so (Lammers et al., 2011). This was equally true of men and women. Clearly there could be many factors implicated, such as increased attractiveness and opportunities that come with higher status. It might also be indicative of an interaction between sexual desire and power/dominance (Chapter 15).

  Buss (2005) proposes the following logic. Women are often able to secure matings with males who are more attractive than their partners and thereby able to link up with genes that help to encode for attractive offspring.

  Co-marital and orgiastic sex

  Orgiastic sex can be better understood in terms of the provision of novelty, variety and the forbidden. Some sex workers have always offered their services to males for this (of course, at a price!) and orgies have always formed a very common image in pornography.

  Consider also consensual ‘extramarital’ sex, with which obtaining variety seems to be at centre-stage. Although a minority taste, there is a significant number of married couples who engage in consensual ‘extra-pair activities’, sometimes termed ‘co-marital sex’ and ‘swinging’. This ranges from the couple parting to different bedrooms, through seeking an extra male, female or couple to join the pair. Participants commonly report deriving pleasure from watching their partner having sex with another person. Later fantasies are often fuelled by such imagery.

  One of the principal reasons given for swinging is to obtain sexual novelty and thereby to revitalize an existing relationship (Stephenson, 1973). Another is to feel a buzz by engaging in the forbidden (Jenks, 1998).

  The basis in the brain

  Zillmann (1986, p. 193) relates the phenomenon of habituation to the loss of arousal of the sympathetic branch of the autonomic nervous system with repeated exposure to the same stimulus and suggests:

  that loss of libido is often nothing less and nothing more than excitatory habituation to sexual stimuli … The characteristic comment of sexually dissatisfied intimates who are breaking up – namely, that ‘the excitement has gone’ out of their relationship – epitomizes the suggested mechanics. Despite potentially unimpaired genital functioning, and frequently because of it, unexcited sexual activities are deemed drab and unfulfilling.

  Guilt associated with infidelity might, according to Zillmann, be expected to boost arousal level.

  The powerful role of novelty is difficult to reconcile with the notion that desire is based upon an autonomous intrinsic sexual drive. Rather, novelty can be better accommodated under the kind of dopamine-based incentive principles developed here, since evidence points to dopamine activity being sensitive to novelty.

  Novelty appears to be a means of boosting activity in the dopaminergic pathway that projects to the nucleus accumbens (Bardo et al., 1996). An unexpected reward is particularly strongly excitatory (Panksepp and Moskal, 2008). Repetition of stimulation and prediction of the response shifts control away from this pathway and towards brain processes underlying habit (Alcaro et al., 2007). There are differences between animals, with strong novelty-seekers also being those most ready to self-administer drugs.

  Differences in novelty-seeking and drug-taking in humans, as with rats, are in part the result of genetic differences between individuals. Differences between humans in number of sexual partners have been investigated and linked to genetica
lly based differences in dopaminergic systems (Guo et al., 2007).2 One genetic difference3 was associated with the number of sex partners in young men but not in young women. The researchers suggested that social differences could mask the influence of this particular genetic difference in women. Men with high levels of testosterone tend to show higher levels of sensation-seeking and have more extramarital sexual relations than those with lower levels (Booth and Dabbs, 1993). Testosterone exerts a role via dopaminergic systems.

  For sexual behaviour, there are at least two aspects of novelty and both would be expected to reinforce their effects in terms of the activation of dopamine and thereby wanting. First, there is the novelty of sensory features; those of the novel potential partner differ from those of any established partner. Secondly, there is the uncertainty of the reaction of the novel partner, the moves being unpredictable.

  Let us contrast two extreme cases. First, there is that of meeting someone attractive but totally unavailable, for example someone showing no interest and who is carefully guarded by a jealous partner. The calculated probability of success might be zero. Secondly, there is the case of a long-established partner, with whom sexual behaviour follows a regular and predictable sequence. Here the probability of success might be 100 per cent or close, often with the sequence of moves and reactions highly predictable. Control has shifted to a more automatic mode (Anselme, 2010). If we extrapolate from studies on non-humans, neither a 0 per cent nor a 100 per cent estimate of success in obtaining reward is a powerful trigger to dopamine release (Anselme, 2010). Rather, the strong trigger is somewhere between these extremes, with a maximum at 50 per cent, where uncertainty is at its maximum. A similar logic applies to the addictive lure of gambling, where the pay-off is uncertain.

  The quest for novelty and attempts to resist it raise the issue of inhibition, the topic of the next chapter.

  In summary

  The term ‘Coolidge effect’ refers to an increase in sexual desire as a result of the appearance of a novel partner.

  Human ingenuity finds various ways of exploiting the capacity for such elevated arousal.

  The effect appears to involve a heightened level of activity by dopamine systems in the brain.

  Twelve Inhibition, conflict and temptation

  But I see another law in my members, warring against the law of my mind, and bringing me into captivity to the law of sin which is in my members.

  (St Paul’s Epistle to the Romans 7: 23)

  The nature of inhibition

  The means by which desire is inhibited (‘restrained’) represent an important feature of ‘how desire works’ and will be explored here. St Paul describes one form of conflict: that between the will and desire. Throughout the ages, prohibitions and disapproval of ‘inappropriate desire’ and its expression seem as evident as desire itself.

  Social harmony requires that all societies have curbs on sexual behaviour, whether of an aesthetic, legal, cultural, religious or moral nature. Some potential inhibitors of sexual desire, such as public censure, have eased with more relaxed attitudes. However, jealousy, anger and disgust over what are judged to be unacceptable desires in others are still universal. For some, the existence of desire and its inhibition represent proverbial conflict.

  The popular press expose illicit, excessive, dangerous or unconventional desire, where the implicit assumption is that the guilty party should have known better and have exerted inhibition. A favourite target is when behaviour violates fidelity or threatens national security, or both. A person, or society, might wish to increase inhibition, as in restraining personally harmful excesses or socially unacceptable and illegal behaviour. By contrast, others might feel excessively inhibited in their expression of sexual desire, though they rarely make the headlines. They might wish to lower inhibition, as in trying to overcome excessive and unwanted restraints. Erectile disorder caused by excessive worry about performance can be mediated by excessive levels of inhibition (Janssen and Bancroft, 2007).

  Inhibition is not the same as absence of excitation (Janssen and Bancroft, 2007). Rather, inhibition is an active process, pulling in the opposite direction to excitation. Inhibition either lowers desire or lowers the chances that it will lead to sexual behaviour. This chapter considers the nature of inhibition, how it interacts with desire and what this says about desire.

  There appear to be at least three types of inhibition that can be exerted on sexual desire and its expression in behaviour (Bancroft, 2009; Toates, 2009). Inhibition can arise from:

  1 orgasm/ejaculation, acting directly to lower arousal and desire;

  2 external stimuli, that is physically present unwanted and often aversive stimuli, acting sometimes non-consciously and directly to lower arousal and thereby desire;

  3 intentions. Cognitive processing involving a competing goal (e.g. ‘I intend to remain faithful’) might either lower desire directly or lower the chances that desire will give rise to sexual behaviour. This would arise typically through a conscious cost–benefit analysis of the situation.

  The description ‘excessive inhibition’ might need to include which of the three types of inhibition is excessive (Bancroft and Graham, 2011). One person could have excessive inhibition as an automatic reaction to the situation (factor 2), whereas another might ‘put on the brakes’ as a conscious choice (factor 3). Women might well be more predisposed to exert greater levels of inhibition (Bancroft, 2009), acting at levels 2 and 3.

  Bearing in mind this distinction, the chapter will now describe some triggers to inhibition.1

  Orgasmic (sexually specific) inhibition

  Inhibition triggered by orgasm is specific to sexual desire and is usually more evident in men than women. In men, orgasm normally tends to reduce further desire or makes penetrative sex more difficult due to weakness of erection. It appears not to be the loss of seminal fluids as such that lowers desire, but rather the process of orgasm organized in the brain. Something lowers the degree to which desire can be triggered and it presumably lowers the ability of sexual stimuli to trigger the dopamine system. Accompanying such satiety, other stimuli such as food normally retain their attraction value, so this form of inhibition is specific to sexual desire.

  For the male, the functional significance of this inhibitory factor is that, immediately following ejaculation, sexual behaviour would not be successful reproductively. Some minimal time spent away from sexual activity allows the replenishment of the supply of seminal fluids. That women tend to be more multi-orgasmic than men is presumably related to the fact that there is nothing needing regeneration following orgasm and that sex could be pursued with advantage immediately.

  Neurochemicals, such as serotonin and opioids, are released at orgasm and implicated in satiety (Georgiadis et al., 2012).2 Neurons employing serotonin project to numerous brain regions, including the nucleus accumbens. Through this route they could oppose the excitatory influence of dopamine, thereby mediating sexual satiety. Higher than normal levels of serotonin appear to be implicated in low sexual desire. Endogenous cannabinoids3 are also involved in satiety.

  Prolactin appears to be secreted in relatively large amounts at the time of orgasm, acting both on the brain processes underlying desire and genital function (Krüger et al., 2006). However, it is released in both sexes and yet, if implicated, would have much less effect in women (Levin, 2003). The release of oxytocin that accompanies orgasm is another candidate to act in an inhibitory role (Carmichael et al., 1994). The muscular contractions that accompany orgasm in men and women might also be implicated in satiety. For women who attain multiple orgasms, the final and satiating orgasm in the sequence is accompanied by high levels of release of oxytocin and particularly strong muscular contractions.

  Differences in feedback from the genitals could play a role in the sex difference. Men pay more attention to genital signals than do women in so far as excitation of sexual arousal is concerned and it could be that such signals play a greater role in loss of arousal.


  Whatever the exact process, it is clearly something specific to sexual behaviour and not a general process.

  Inhibition from physically present stimuli

  There are various physically present events in the here and now that lower sexual desire. Fear and pain, for example pain triggered during sex or a sudden noise indicating that attention might be better directed to defence, can do so. Another example is sexual disgust. Exposure to women’s tears shed from emotion has the effect of reducing men’s sexual arousal and testosterone levels (Gelstein et al., 2011). This could be a defence mechanism adapted to protect a woman from unwelcome advances. Also in this class of inhibition is the failure of erection, which could trigger the fear of performance failure (Janssen and Bancroft, 2007). In men, this can set up a vicious circle whereby inhibition is exerted on sexual arousal with a subsequent self-fulfilling prophecy of erectile difficulty.