How Sexual Desire Works- The Enigmatic Urge

by Frederick Toates

  Griffitt et al. (1974) exposed participants to a sexual stimulus and observed their immediately subsequent behaviour. Relative to those not sexually aroused, both males and females who found the stimulation to be positively arousing tended subsequently to look more at members of the opposite sex and to sit closer to them. By contrast, those who found it aversive tended not to look more at the opposite sex and even to sit further away from them.

  The notion of erotophilia–erotophobia has a certain predictive value (Fisher, 1986), which forms a foundation of what is termed the ‘sexual behaviour sequence model’. The essence of this is described in the next two paragraphs. Knowing someone’s location on the continuum means that it is possible to predict with better than chance accuracy their reactions to a new sexual stimulus or suggested scenario. For example, in one study, a man’s location on the scale predicted better than chance his reaction to buying condoms and even his evaluation of the sales assistant and the drugstore.

  People appear to make assessments of the expected outcome prior to engaging in sexual activity (Fisher, 1986). For example, fantasy can be employed in conjunction with images of real people or picture representations. The erotophilic individual will tend to obtain positive feelings from such initial forays and be persuaded to advance, whereas the erotophobic will tend to derive negative assessments that will be associated with withdrawal. Erotophilic individuals tend to talk openly on sexual matters, masturbate frequently, have a wide range of acceptable sexual activities and plan ahead for sexual encounters by taking such actions as acquiring contraceptives.

  Clearly, the ‘sexual behaviour sequence model’ involves a central brain state that modulates the reaction to external events and situations, causing approach or withdrawal. It is entirely compatible with principles of incentive motivation and learning of incentive value and it is hard to see how it would lend support to the notion of sexual drive as some sort of energy that seeks discharge. One would need to propose ‘negative drive’ to describe those people who react with erotophobia.

  Accommodating cultural differences

  The model advanced here can accommodate cultural differences in sexuality. In the context of the sexual behaviour sequence model, some cultures are predominantly erotophilic, for example that of Mangaia, whereas others are strongly erotophobic, for example the Irish island of Inis Beag (Fisher, 1986). Allocation of a culture on this scale allows a prediction of its behaviour at better than chance levels. For example, in Inis Beag a whole range of activities, not only premarital sex but such things as simply revealing too much of the body in swimming, are condemned. A country such as the United States or United Kingdom would be somewhere between the extremes, while Sweden or the Netherlands would be more in the erotophilic direction.

  Accommodating gender differences

  While noting men’s much higher testosterone levels and thereby higher intrinsic contribution to sexual desire, some have speculated that women’s sexual desire is more heavily situation-dependent than is men’s (Tolman and Diamond, 2001). Women are triggered by a wider range of cues (e.g. emotional empathy) and tend to express a more nuanced desire than men. Some degree of bisexuality is attractive to more women than it is to men. To say that men have a higher sex drive than women could lead to an assumption of some intrinsic property of the body that can be measured outside context. Leiblum (2002, p. 62) suggests: ‘women’s sexual desire may be more a function of external motivation than internal insistence’. This externally triggered desire might be more easily lowered in women as a result of unpleasant experiences of sexual behaviour, for example clumsy or painful sex or dysfunction in the relationship (Leiblum, 2002; Wood et al., 2006).

  Much of the triggering of sexual desire and arousal reflects such intentionality and guidance by future projected events. However, some sexual desire appears to be triggered automatically by powerful stimuli in the environment. It appears that women’s sexuality is more determined by expectations of sexual pleasure set into a context of meaning, whereas men’s is more automatically triggered by physical attributes of the attractive individual. Typically, attachment and emotional empathy are likely to contribute more heavily to women’s desire than to men’s.

  How would the incentive motivation model work?

  For sex, the incentive would typically be the pull exerted by another individual. As Hite (2003, p. 48) states: ‘Most men in my research feel that their desire is largely inspired by a particular desired individual, or by particular images or fantasy.’ The term ‘desire’ seems to capture the essence of the broader term ‘incentive’ and of being pulled into action to achieve something presently unavailable to us (Regan and Berscheid, 1999). It reflects a wish for – a ‘wanting of’ – sexual contact, an engagement of the mind with sexual thoughts, fantasy and imagery.

  A similar though simplified principle applies to non-humans. Thus, the pull can also be seen in an animal being attracted to locations associated with a ‘mate’ such as a location in a maze where sexual behaviour had taken place in the past. It can be measured by how much work an animal is prepared to perform in a Skinner box,2 to gain access to another animal. Lever-pressing reflects attraction towards a goal of access. For humans, a measure is to ask people about their subjective conscious feeling of desire, a ‘psychological state’ (Regan and Berscheid, 1999).

  Incentives rather than drives

  In the view advanced here, rather than internal factors, such as hormone levels, driving the animal, human or otherwise, they modulate the power of the incentive to exert a pull. Changes in the attraction value of the incentive correspond to changes in sensitivity of regions of the brain, termed motivational processes. These regions are sensitized by sex hormones (Chapter 2). Such a view has now largely replaced drive interpretations inside scientific sexology (Both et al., 2006).

  In this view, there are changes in the strength of motivation with changes in the proximity of the incentive. This has health and security implications: good intentions of restraining one’s sexuality when at a safe distance from attractive others might get forgotten in a state of heightened arousal triggered by their physical presence. Cognitive distortions can appear that fly in the face of rationality, an important consideration in safe-sex campaigns. A decision to use condoms made when planning an evening doubtless sometimes gets corrupted in the heat of the moment (Chapter 15).

  According to an incentive view, the consequences of sexual activity modulate the value of incentives. Successful sexual interaction increases the value of the particular incentive and its context, whereas sexual failure will lower incentive value (Woodson, 2002). People commonly experience a reduction in tension following orgasm (Meston and Buss, 2009). Some bodily condition is clearly rather abruptly reversed. Many women liken the tension release of orgasm to that associated with urination and indeed some of these worry that this might happen (Basson, 2000). However, in incentive terms the tension was not what motivated the initial sexual desire. Rather the tension was introduced into the system by the desire. In incentive terms, the tension release would be expected to modulate future incentive value by making the partner more desirable and thereby the sexual act leading to orgasm more likely to happen in the future. In women, oxytocin levels in the blood rise immediately following orgasm (Blaicher et al., 1999). This could well consolidate the incentive value of the partner and sense of belonging with this person.

  So, according to an incentive view, a particular bodily state sometimes termed ‘sexual arousal’ tends to turn attractive sexual stimuli into wanted stimuli associated with the anticipation that interaction with them would bring pleasure. Evidence to favour this interpretation was provided in a study that first triggered sexual arousal in participants of both sexes by asking them to view an erotic movie. Compared to unaroused participants, those given such prior arousal subsequently rated sexual features of attractive images they viewed as still more attractive (Istvan et al., 1983). However, prior sexual arousal caused participants to rank images that
they found sexually unattractive as even less attractive. Such polarization argues against a simple drive model of sexual desire and, as the authors argued, arousal enhanced the salience of sexual stimuli. There is not some factor inside the body seeking discharge and thereby searching for any means to achieve it. Similarly, bodily arousal induced by physical exertion or humour tends subsequently to make an attractive partner still more attractive but an unattractive partner less attractive (White et al., 1981).

  Failure to attain orgasm is something that underlies much of women’s lack of satisfaction with sex (Hite, 2000). In incentive terms, this is not a failure to correct a regulatory disturbance. Rather, it is a failure to complete the ascent of a gradient of increasing desire, arousal and pleasure – a failure to attain an ultimate hedonic goal. Prospective manufacturers of ‘sexual dysfunction pills’ for women are misidentifying the source of the problem (Hite, 2000). The problem does not lie within the biology of the body but in the communicative skills of the couple and stimulation that the woman receives, which is often inadequately targeted to the clitoris in penetrative sex.

  To appreciate the essence of an incentive view, consider that gambling can come to exert just as strong a pull on behaviour as can sex (Orford, 2001). Yet, surely, gambling is based upon experience with gambling tasks rather than any intrinsic ‘gambling drive’. Once hooked, gamblers can suffer from all manner of bodily disturbances, such as a knotted stomach. However, the bodily disturbance is not the basis of the initial desire to gamble but the outcome of the ups and downs of gambling experience.

  To take stock, the essence of the incentive–motivation view is that motivation is triggered by:

  incentive objects (e.g. a partner)

  cues associated with them, through classical conditioning

  use of the imagination to represent absent incentives, that is thoughts of them.

  Development: forming incentives

  In an incentive view, the interaction between genes and early environment permits a certain range of potential incentives to become real incentives. Which potential incentives (if any) – for example heterosexual, homosexual or bisexual – come to assume that role will depend upon the idiosyncratic dynamics of gene–environment interaction. Adopting an incentive model is not to come down on the culture side of the so-called ‘biology versus culture’ dispute, since logically there can be no such dispute. Biology is still ‘in there’ in the form of brain processes that preferentially translate particular stimuli into an incentive motivational pull. Hormones – clearly a ‘biological thing’ – play a role. Orgasm – surely a biological process – still sits at centre-stage as a reward and reinforcement for action accomplished and a trigger to label and consolidate the incentive as desirable.

  The objects of sexual desire do not arise completely unchannelled from the limitless possibilities of early exposure, imagination and masturbation. Societies prescribe certain acceptable targets. Depending upon age and parental influences, adolescent sexual desire encounters both social controls tending to inhibit its expression and peer influences that can either inhibit or excite its expression. These are ‘contextual factors’ in terms of the present argument.

  Celibacy and sexual restraint

  For centuries, a number of people in each culture have voluntarily opted for celibacy, often in the cause of religion (Gaca, 2003). As just noted, some cultures experience a highly restricted level of sexual activity (Messenger, 1971). In terms of drive, this would make little sense, since their insides should be disturbed and they should suffer torments. Some doubtless do, but there is no reason to extend this to everyone. In terms of incentives, celibacy makes more sense, since a combination of factors would be seen as responsible. These would include genetics, early development, any sexual experiences and the competition offered by other goals such as to maintain moral virtue. Where a culture emphasizes the necessity for sexual restraint in order to achieve religious salvation, there will be the potential for competition with sexual desire (Messenger, 1971).

  Fear and feelings of inadequacy can conspire, it would appear, to produce a kind of involuntary celibacy, a probable example being J. M. Barrie. Chaney (2005) describes the extreme shyness that the creative genius felt towards women (p. 40):

  It was also a natural defence against his sense of failure at making any impression on them at all. But if this young man couldn’t attract attention by his appearance, he was to discover there were other ways by which he could hold centre stage.

  Being unusually short, Barrie was highly sensitive about this and the failure that he perceived to result from it. Though engaging in ‘outrageous flirting’ and subject to repeated infatuations, he feared going further than this. Chaney (2005, p. 269) writes:

  Although it is virtually certain that he never consummated any of his numerous flirtations, he doesn’t appear to have been essentially different from other trophy-hunting males. He never ceased to need the thrill of collecting a succession of women.

  So, where does this incentive-based system and the restraints upon it fit into the notion of levels of control? The next chapter turns to this.

  In summary

  Sexual desire is not an aspect of homeostatic regulation of a bodily factor outside the brain.

  Rather than drives triggering the human, sexual incentives are a source of action.

  Hormones sensitize the power of incentives to motivate action.

  Frustration arises from the thwarting of desires.

  Five Sex and levels of organization

  The heart has its reasons of which reason knows nothing.1

  (Pascal, 1669/1996, pensée no. 423)

  Charms would not deserve their name if they did not have the power to silence our reason.

  (Casanova, 1798/1958, p. 246)

  Having advanced the case for an incentive motivation model of sex, it is necessary to fit this idea to the notion of levels of organization, exemplified by automatic and controlled processing (Chapter 2).

  Evidence points to behaviour being determined by at least two levels of control in the brain (Carver et al., 2009; LeDoux, 1999; Toates, 1998, 2006):

  an evolutionarily old low-level system, which is (‘automatically’) reactive to specific events in the world. It can sometimes operate at an unconscious level;

  an evolutionarily new high-level (‘controlled’) system that operates at a conscious level and seeks long-term rational goals (e.g. to maintain marital harmony, resist temptation).

  The levels of organization can act in the same direction (e.g. both tending to trigger behaviour) or in opposition (e.g. low level excites behaviour, while high level tends to restrain).

  The low-level system often operates in a way that is not accessible to conscious awareness, though the endpoint of its processing can engage consciousness. This system is fast, reacts to the events of the moment, and poses low demands on processing resources.2 The high-level system represents the conscious and rational mind.3 This system takes into account long-term considerations beyond those of the present moment in time and it takes up a large amount of processing capacity.

  The low-level system can produce either action or inaction (Carver et al., 2009). Powerful incentives can act through the low-level system to engage appetitive behaviour, whereas aversive events can act to cause withdrawal from a situation or immobility. High-level control, in other words ‘executive control’, can sometimes override either of these tendencies, to restrain or energize behaviour. When the capacity for executive control is high, people tend to act according to their conscious intentions and long-term goals. When it is compromised, the lower-level control can dominate, sometimes even against the intentions of the higher-level system. The result is ‘myopia for the future’ and a relative inability to learn from previous mistakes (Schore, 2003). In all of its aspects, human sexuality arises from the complex interdependence between old and new brain parts.

  There are various factors that determine the relative weight of control that is e
xerted at different levels. Each of these is relevant to at least one aspect of sexuality and some of these will be discussed in detail in subsequent chapters. This section gives just a brief overview of these phenomena to show the generality of the principle of levels of control.

  Engaging attention and desire – or not

  At times, attention is captured automatically (‘unconsciously’) by particularly salient stimuli in the world or in memory (‘low-level control’). This can happen in a way that either runs counter to or matches conscious wishes, goals and intentions. The phenomenon known as ‘attentional adhesion’ refers to a process whereby the attention of one individual is grabbed by the stimulus of an attractive person and the individual whose attention is grabbed cannot let go (Maner et al., 2007, 2008). At other times attention towards a particular target is under voluntary conscious direction (‘high-level control’).