How Sexual Desire Works- The Enigmatic Urge

by Frederick Toates

  Forming the social link

  Money (1986) speculated that sexual development has something in common with development of the brain’s control of the limbs. The development of a so-called ‘lovemap’ begins very early in life (p. xvi):

  a lovemap is not present at birth. Like a native language, it differentiates within a few years thereafter. It is a developmental representation or template in your mind/brain, and is dependent on input through the special senses. It depicts your idealized lover and what, as a pair, you do together in the idealized, romantic, erotic, and sexualized relationship. A lovemap exists in mental imagery first, in dreams and fantasies, and then maybe translated into action with a partner or partners.

  …

  sexuoerotic rehearsal play in infancy and childhood is prerequisite to healthy heterosexual lovemap formation. Deprivation and neglect of such play may induce pathology of lovemap formation, as also may prohibition, prevention, and abusive punishment and discipline. Conversely, exposure too abruptly to socially tabooed expressions of sexuoeroticism may traumatize lovemap formation.

  From the age of 5 or so, flirtatious rehearsal play sometimes takes the form of boyfriend–girlfriend romance. Hugging, kissing, genital exhibition and even exploration of the genitals of other children is commonly observed at a young age (Ford and Beach, 1951). It appears that rather early in life young children assimilate that there is a mysterious and forbidden aspect to such adventures, presumably a source of arousal. Boys tend to show such sex play, whether heterosexual or homosexual, much more frequently than do girls and often this is with older children (Kinsey et al., 1948). Whether adults approve, ignore or disapprove of such early sexual exploration and play, it is seen widely across cultures (Ford and Beach, 1951).

  The degree of flexibility in sexual orientation and desire would be expected to vary between individuals as a function of early hormonal and later social environments. Bancroft (2009) notes that the onset of masturbation occurs (if at all) over a wider range of ages in girls as compared to boys. He speculates that this could reflect a wider range of time course of hormonal sensitizations in girls.

  In parallel, with the emerging capacity for pleasure from the genitals occurs something that one might call ‘prototype courtship’, with boys typically displaying this towards their mothers or other females and girls towards fathers or other males (Money, 1990). Kindergarten romances are seen sometimes with genital play. An absence of so-called sexual rehearsal play might well drive fantasy in unusual (so-called ‘paraphiliac’) directions (Money, 1977).

  Parental reactions could enter into associations with the genital reaction. There is a tendency for erotophilic parents (e.g. who discuss sexual matters openly) to trigger erotophilia in their children, while erotophobic parents (e.g. those refusing to discuss sex) tend to trigger erotophobia. Sexual disapproval can become associated with genital sensations and hence the roots of aversion (‘erotophobia’) established (Fisher, 1986). At the time when strong emotional attachments to the parents would normally be forged, the child’s sexual trajectory is vulnerable to disruption. For example, abuse can get ‘wired into our brains’ and establish aversive associations, thereby setting desire in a maladaptive direction. The abused child has an increased risk of being an adult abuser or seeking abusive relationships (Doidge, 2007).

  Fisher (1986) suggests that early learning can form a foundation for later more sophisticated learning of meanings to be attached to sexuality, for example expectations about sexual action and the emergence of sexual fantasy. A cross-cultural study done in India (Fisher, 1986) compared two groups of Bengali-Hindu students. One group had been brought up in traditional rigid orthodox families and they tended to be erotophobic in outlook, whereas the other group was raised in a more liberal and sexually permissive environment and tended to be erotophilic.

  Children pay attention to and react to the behaviour of others. Social learning theory (Akers, 1985; Bandura, 1977) suggests that children learn behaviour by a mixture of reinforcement and imitation of models such as parents, peers and television actors. These days media play a dominant role in providing education on sexual matters, for example in showing what is right and wrong, thereby acquiring the description ‘super peer’ to teenagers (Samson and Grabe, 2012). The content of other’s speech gives indicators as to how to behave. Early in life, the child learns from caregivers ways of social interaction (Schore, 2003). By direct experience, the child’s behaviour is rewarded or punished and thereby she or he forms expectations of the kind ‘if I do this, I can anticipate this reaction from the other person’. Observation of models being rewarded, as in deriving pleasure from their actions, increases the tendency of the child to try to emulate the actions observed – so-called vicarious reinforcement.

  It appears that these processes can contribute to both prosocial and deviant behaviours. For most people controls are such as to maintain conventional standards of conduct but, if lacking or of a deviant kind, they might strengthen deviant behaviour. Sexually aggressive young men usually have sexually aggressive friends (Hogben and Byrne, 1998). If there is little in the way of any such influence, the child is in something of a vacuum and might accidentally discover deviant ways of acting.

  Again, the critical eye of Skinner can be relied upon (Skinner, 1976, p. 128):

  I discovered that concealment of sex varied among ethnic groups. I was once crossing a bridge over Drinker Creek just outside of town and saw ten or twelve Italian boys who had been swimming and were now sitting naked on some warm rocks along the bank. They were handling their genitals and the oldest boy was being greatly admired for the size of his erection. The younger were doing their best to emulate him. There was no homosexual contact.3

  This exemplifies an aspect of social learning (Hogben and Byrne, 1998): the boys were hoping to achieve the result (‘reward’) being modelled by the oldest boy.

  It must be rare that children actually learn by direct observation of sexual behaviour (though internet pornography is now a complicating factor). More generally, they would learn sex roles and who associates with whom on intimate terms.

  Of course, parents do not live in a social vacuum but rather their own attitudes and behaviour reflect to some extent the bigger society. The existence of ‘social norms’ is universal and appears to be old in evolutionary terms, though cultures differ widely in what constitutes their social norms (Sripada and Stich, 2007). Social norms rely upon rewards for conformity, for example social approval, while subtle and not-so-subtle social punishments are given for their violation, such as malicious gossip and ostracism from the group. Most societies have the social norm of condemning incest and most have rules concerning the permitted sexual activity of young people, though what these are varies widely across cultures. To comply with a social norm establishes a powerful source of motivation, though of course not everyone does comply with every social norm. To violate a social norm can trigger anger and outrage. While parents generally have conservative social norms, a peer group might typically be permissive.

  Learning specific targets of desire

  How does sexual desire come to be directed to particular targets? Laws and Marshall (1990) placed the weight of explanation upon classical and instrumental conditioning (Chapter 2), as follows.

  Suppose that, in the child, arousal of the genitals occurs for some reason. Maybe it simply arises spontaneously or physical stimulation of some kind (e.g. auto-stimulation) triggers it. Suppose now that this reaction is accompanied by the sight, sound or touch of a potential erotic stimulus, for example another individual, either in reality or in the imagination. This would commonly be a member of the opposite sex but it might be of the same sex. Because of the coincidence in time, the potential erotic stimulus (‘potential incentive’) comes to form an association with genital arousal. The potential erotic stimulus becomes an actual erotic incentive.

  Based on the ideas of Martin Seligman, the researchers appealed to the notion of ‘preparedness’ of the m
otivational system. Certain things, such as particular perceptions, are more likely than others to form an association with genital arousal. From evolutionary considerations, heterosexual stimuli would be the most likely candidates. Conversely, the system would be ‘contraprepared’ to form associations with inanimate objects. Laws and Marshall note a number of features of such association formation with ‘highly prepared’ stimuli:

  An association can be formed with only a few pairings of events.

  There is a high degree of specificity and selectivity to a particular stimulus in its capacity to form an association.

  Once formed, it is difficult to break the association (i.e. ‘extinction’ is difficult).

  Prepared associations are said to be ‘non-cognitive (i.e. primitive) and not readily modifiable by information. This explains why deviant sexual behaviour is so resistant to modification’ (Laws and Marshall, 1990, p. 211).

  Laws and Marshall argue that the consequences that immediately follow sexual arousal triggered by a stimulus can exert a powerful role in changing the future motivational strength of the stimulus. Consider an example of strengthening behaviour, that is positive reinforcement: if a child attains the pleasure of orgasm in the presence of a particular stimulus, the power of that stimulus to produce arousal in the future is increased. Orgasm through masturbation accompanied by particular imagery might consolidate the strength of the imagery as a sexual incentive. Conversely, if something aversive occurs, the future probability of the stimulus triggering arousal might be lowered, that is a procedure described as punishment. Social disapproval is one such example. Alternative unpunished fantasies could arise and possibly lead to unusual sexual preferences. Once the first-order stimulus for arousal has been established, stimuli that are associated with it can also acquire a potential for triggering arousal. The authors suggest that, through masturbation and the use of fantasy, there can be some extension to the range of stimuli that elicit arousal.

  Incest and its avoidance

  Basic principles

  The very young child assimilates into its memory features of the nearest humans, normally the parents. When the child is older, reproductive success requires that similar features, most obviously human facial characteristics, trigger sexual attraction and bonding. Principles of adaptation suggest that the child needs to form an internal representation of an opposite sex individual that has a motivationally attractive value. The first opposite sex individual that the child will encounter is likely to be a parent or sibling.

  However, here lies a ‘dilemma’: it would be maladaptive if the child were to form too close an attraction to the precise features of the opposite sex parent or siblings. This would increase the chances of later incestuous relations developing and decrease the chances of later sexual attraction to those outside the family. One’s first reaction is, probably correctly, to think of the risks associated with incest. However, it would seem that there are costs and benefits attached to both incestuous and non-incestuous relationships (Bagley, 1969). As a cost, an incestuous relationship increases the risk of genetically based disorders, but this is only an increased probability, not a certainty. Since some degree of incest prohibition appears to be universal, albeit with slightly different precise rules of prohibition across cultures (Ford and Beach, 1951), it would seem that costs have outweighed benefits in evolution.

  So, how is the problem solved and incest avoided? A dispute in the history of psychology pitted two perspectives against each other. On one side was the Finnish anthropologist Edward Westermarck, who in 1891 published an influential book called The Nature of Human Marriage. How is it, Westermarck asked, that there appear to be universal aversions against sexual relations between close kin? He suggested that there are biological processes that cause a sexual aversion to those with whom one has the most contact in early life, typically, parents and siblings. Since incest brings a heightened risk of the transmission of genetic disorders, it is of adaptive value to develop a sexual attraction only to non-kin. The process might be described as a form of ‘negative imprinting’. The term ‘imprinting’ describes a phenomenon in which young animals (e.g. geese) develop an attraction to the first moving thing that they see after birth/hatching. Negative imprinting refers to the development of an aversion. So, according to this perspective, incest avoidance is mediated through inhibition of sexual desire. A possible candidate to mediate incest avoidance is represented by pheromones; pheromones from one’s own family are less attractive than those of others outside the family (Wedekind and Penn, 2000).

  A sociological rather than a biological interpretation of incest was proposed by Sigmund Freud. Freud suggested that social taboos act against incestuous relationships in order to avoid the consequences of incest. If there were no incestuous desires to be resisted, there would be no need for such taboos. There is reason to doubt that this captures the whole picture. Are there really strong and burning incestuous desires to be prohibited in the first place? If, on average, incestuous mating is disadvantageous compared to mating outside the family, would evolutionary processes, metaphorically speaking, have left it to cultures and laws to ensure that it does not happen? After all, if adultery and homosexuality are anything to go by, legal and social sanctions do not have a very good track record in suppressing strong sexual desires (Lieberman and Symons, 1998).

  It is more likely that the sociocultural and legal prohibitions reflect something observed to occur within the individual, that is some aversion to sex with siblings. In this case, it would fit with the general picture emerging here: a biological level of organization with a cultural overlay. By analogy, there are social and religious prohibitions against sex with animals and corpses but it is hardly the case that most of us have an urge to engage in these activities, only restrained by fear of social censure. More likely the prohibitions are an extension from the individual experience of disgust – others should be protected from an experience that we feel to be disgusting (Fessler and Navarrete, 2004).

  The evidence

  Among non-human species, such as a number of non-human primates, incestuous mating is almost always avoided. This would suggest a biological basis to the phenomenon. Could this really be lost in the evolution of humans?

  Consider both sibling incest and parent–child incest. Concerning the former, a number of studies suggest that close physical proximity in early years triggers sexual aversion (Fessler and Navarrete, 2004). Two cases are frequently cited in support of a biological basis for human incest avoidance, as follows.

  In Taiwan, some families fostered their daughters, to be brought up in the homes of boys, who, it was intended, would later become their husbands (Lieberman and Symons, 1998; Wolf, 1995). This would seem to offer a natural experiment to distinguish between biological and sociocultural accounts of incest avoidance. If the biological account is correct, some sexual aversion would be expected when the children later marry. This would be indexed by such ‘proxy measures’ as relatively low fertility and high rates of divorce and extramarital affairs. If the sociocultural account is true, no such effect would be expected, since the ‘incestuous’ relationship was actively encouraged by both sets of parents. It would seem that such marriages were less successful than those between partners not having been brought up together. It appeared that rearing children together lowered later sexual desire.4

  The other study is that of the Israeli kibbutzim (Shor and Simchai, 2009). It was observed that children growing up in close proximity to each other rarely developed intimate sexual relationships or married one another. Proximity was thought to trigger sexual aversion. However, this has been questioned. A relationship of the marriage kind is not necessarily a perfect measure of attraction and so the researchers conducted in-depth interviews with people who were raised in kibbutzim. Rather than explicit sexual aversion, they found a mixture of indifference or attraction in retrospective consideration of sexual feelings. In contrast, the participants did express aversion to sexual relations with close
relatives. Based upon the witness of those brought up in kibbutzim, the reason that they gave for why sexual relationships did not develop was that they would threaten group cohesion and were against society’s expectations.

  Lieberman et al. (2003, 2007) investigated the relationship between the length of time students had spent in their family with opposite-sex siblings and the disapproval of incest that they expressed. The more contact the student had had, the stronger was the disapproval of incest, supporting the Westermarck hypothesis that contact triggers aversion to incestuous sex. Even when the other children in the family were unrelated (i.e. adopted or from one parent’s earlier marriage), an almost equally strong aversion was found. This suggests that the aversion arises from physical exposure rather than genetic relatedness as such. Of course, normally such exposure would be closely correlated with genetic relatedness. Length of exposure predicted aversion to contact with one’s own siblings and the degree of disapproval felt to others having incestuous relationships. Thus, incest avoidance cannot arise simply from habituation to a sibling since this would not explain active disapproval of incest by people unknown to the individual. Rather, this points to an active aversion (Fessler and Navarrete, 2004).

  As yet another factor, we might expect females to be more sensitive to incest than males, since the cost of suboptimal mating is so much higher in females (Lieberman et al., 2003).