How Sexual Desire Works- The Enigmatic Urge

by Frederick Toates

  Psychologists researching a range of desires and temptations build upon the observation that stimuli can engage processing by the brain at an unconscious level (Hofmann and van Dillen, 2012). When presented with a new stimulus, its qualities of good or bad are extracted first at a rapid unconscious level, and only later, if at all, is the stimulus subject to conscious processing (Elliot, 2008). This rapid analysis gives a predisposition to approach or avoid respectively, though there need be no overt behaviour shown. The quality of the evaluation, good or bad, depends in part upon the individual’s current goals (Ferguson and Bargh, 2008).

  To some extent, the long-term goal can bias attention towards objects that are compatible with achieving the goal and away from objects that are incompatible (Hofmann and van Dillen, 2012). According to Hofmann and van Dillen, the attention-grabbing strength of the stimulus depends upon three factors: ‘stimulus properties’, the individual’s learned association with the stimulus and ‘internal need states’. Since their focus was upon feeding, the third term corresponds to the nutrient needs of the body. On being adapted to sex, it can mean such things as hormone levels and sexual fatigue/recovery, which determine the sensitivity of the brain to sexual stimuli.

  The long-term goal (e.g. ‘sexual scoring’) might be such as to facilitate occupation of the conscious mind with erotic information. Once there, the desire-related goal might be retained in conscious memory,4 recycled and elaborated upon, triggering strong emotions and associated thoughts and fantasies, exemplified by conscious wanting and craving. The ability to engage conscious processing would depend upon such things as novelty of the stimulus and its hedonic ranking. Occupation within conscious memory can release what is termed ‘gravitational pull’ or a ‘magnet effect’, in which further congruent and supportive cognitions (e.g. sub-vocal statements – those words that we silently ‘speak’ to ourselves – that justify indulgence) are brought into awareness (Hofmann and van Dillen, 2012), which can then trigger consciously mediated action directed at attaining the short-term hedonistic goal.

  Under other circumstances, long-term goals (e.g. to maintain diet, keep a vow of chastity) might be at odds with pursuit of a short-term goal; that is, there is temptation (Chapter 12). Under these circumstances, the signal arising from the potential sexual stimulus might be sufficiently inhibited and hence not reach conscious awareness. Inhibition can arise from the presence of long-term goals that bias the early stages of processing, for example to block the processing of sexual stimuli. Even if the desired object is consciously processed, further engagement might still be resisted if the long-term goal is sufficiently strong. However, in any mental struggle the short-term goal, of course, might win. Any counter-statements, associated with long-term goals, might be forced out of conscious awareness.

  Consider a person with drug experience, who is not actively seeking drugs at the time and has the general intention of resisting them (Tiffany, 1990). The individual’s sensory systems detect a drug-related cue, such as the smell or sight of a drug, and attention is drawn towards it in an automatic fashion. Detection of the cue and the start of approach behaviour might be non-conscious, but then the situation is brought into full conscious awareness with a risk of relapse. Similarly, sex researchers suggest that sexually potent cues, for example the form of an attractive individual in reality or in a picture, can grab attention even before we are consciously aware of their presence. These cues can subsequently be ‘demanding’ of attention, displacing other items from conscious awareness (Spiering and Everaerd, 2006).

  Suppose that, for example, a paedophile has a tendency to move unintentionally near to children’s swimming pools and would thereby be drawn towards those habits that he is trying to resist. Forewarned can be forearmed; the person might try to anticipate where trigger cues will appear and avoid such contexts. Failing this, the strategy might be to have a reminder of restraint, such as wearing a bracelet engraved with a warning, which can be consulted when tempted (Chapter 12). Another strategy is to have an incompatible behaviour already primed, so that the individual is diverted from the trigger cues (Tiffany, 1990).

  Resisting temptation exemplifies the competition between low-level and high-level controls. The low-level control might effortlessly pull the individual towards the incentive, whereas any resistance will call upon full conscious controlled resources, something which is effortful and can be exhausting (Tiffany, 1990). Again, most research has been done into drug-taking, but the principles would seem to be general.

  Of course, erotic targets do not exist only in the outside world but can be generated in the form of imagery (Kavanagh et al., 2005). These can also be automatic (e.g. popping into awareness without effort) or controlled (e.g. a deliberate elaboration of the initial image).

  Sexual arousal

  How should ‘sexual arousal’ be measured: as the reaction of the genitals in terms of blood flow (in the male erection) or how aroused the individual feels? Arousal of the genitals might correspond to how aroused a person feels but this is not invariably so, especially in the case of women (Laan and Janssen, 2006) (Chapter 9).

  For women, a sexual stimulus, such as an erotic picture, triggers a fast automatic reflex-like state of arousal as measured by increased blood flow at the genitals (Laan and Janssen, 2006). However, this does not necessarily correspond to a state of subjective arousal, as measured by how she feels. Subjective arousal results from conscious controlled processing that takes into account not only genital arousal but also various personal assessments, conflicts and intentions. She might feel no subjective arousal, in spite of an objectively aroused state of the genitals. Indeed, the genital reaction still occurs even if the woman later reports that the sexual stimulus was distasteful to her.

  Inhibition

  Inhibition upon sexual arousal can occur automatically, for example in response to a loud noise or unpleasant odour. However, it can also act at a high level as a conscious intention to inhibit arousal or to inhibit putting desire into action. This is discussed in detail in Chapter 12.

  Overcoming resistance

  Someone might be depressed, with a tendency to passivity or withdrawal from any sexual contact. However, a higher-level conscious goal might move the individual into sexual activity from a sense of duty or empathy.

  In some cases, women engage in unwanted sex to please or appease a partner (Meston and Buss, 2009). Imagine a woman who no longer finds her partner attractive and has no desire for sex. For example, he might have a problem with alcohol and personal hygiene. However, she obliges out of duty and sympathy. This is the opposite situation to one of temptation, described earlier. Her short-term goals might even be based upon an automatic disgust reaction, which, all things being equal, would cause her to distance herself from the situation. However, this influence is overridden by a long-term goal like sympathy or duty. Engaging in sexual behaviour requires the exertion of the woman’s conscious effort such as to resist the commands of the short-term goal.

  Species differences

  The proportion of automatic to controlled processes differs between species. For example, mating in rats is stereotyped, much the same from one animal to another (Beach, 1947). It is largely under the control of structures that specify what to do when in the presence of a sexually motivated partner. A rat Kama Sutra would be a rather boring but mercifully very short book. By contrast, evolution has given humans a brain with a great deal of flexibility and, acting at a conscious level, capacity for creativity. This is reflected in the endless variations that people find in terms of the nuances that excite them sexually and the complex agendas that people are able to bring to their sexual interactions (if they choose to!). It is hard to imagine that any other species has anything like the rich fantasy world of humans associated with, say, the sexually exciting notion of the forbidden (C. Wilson, 1988). As the biological basis of this richness, the cortex has taken over more control of sexuality in humans than in other species (Zillmann, 1984).

  Gende
r differences in sexual desire

  Men tend to place more weight upon raw stimulus information on the female form in determining their sexual desire and arousal, whereas women tend to place more weight upon meaning (Laan and Janssen, 2006). For example, what a male’s behaviour signifies to the woman in terms of talent and intelligence plays an important role (Bancroft, 2009).

  Learning

  As a very general principle, with extensive practice at a given task, the level of control becomes more habitual and sequences of thought and behaviour tend to be run off automatically. As a result of this, automatic control can act counter to conscious intentions. A motorist might repeatedly turn off the motorway to Detroit, such that this move has become automatic or ‘habitual’. One day, she is on the same motorway but has the conscious intention to stay on, to go to Ann Arbor. However, she finds herself captured by the familiar road sign and the turn to Detroit, so habit causes her to make the usual manoeuvre. Shortly afterwards, she realizes her mistake and gets back on the motorway.

  When a couple first meet, each might have little idea of what to expect from the other, so behaviour is determined in the fully controlled conscious mode. This contributes to high levels of desire. Over extended periods of time, behaviour becomes more habitual with a subsequent lowered desire. Things probably never become fully automated and organized at a non-conscious level, but there can be an increased frequency of lapses, where controlled processing gives way to habits. According to one survey, a move from novelty to habit is a principal factor in the lowering of desire (Sims and Meana, 2010).

  C. Wilson (1988) applies this to feeding, but it is equally if not more relevant to sex (p. 89):

  my robot valet takes over and does it automatically; in fact, he does it far more quickly and efficiently than ‘I’ could. The main trouble with this mechanical valet is that he often takes over functions I would prefer to keep for myself – for example, when I am tired I eat ‘automatically’, and so do not enjoy my food.

  Cognitive load, emotions and stress

  A negative emotion can move the weight of control to a lower level, as is witnessed in anger and its ‘unthinking’ expression in violence. It can presumably also contribute to an engagement in risky ‘heat-of-the-moment’ sexual behaviour.

  The mental challenge posed by stress can decrease the weight of high-level control and increase that exerted at a low level (Tiffany, 1990). Stress appears to be an important contributory factor to sex addiction (Chapter 17) and sexual assault (Chapters 20 and 21). Under stress, a person sometimes reverts back to an earlier apparently long-suppressed form of sexual behaviour, which has been dormant over the years (Money, 1977). For example, exhibitionism might resurface at this time.

  There appear to be several reasons for this effect. Stress has been particularly studied in the context of drug addiction, where, amongst other factors, having ‘something worrying on your mind’ takes up conscious processing capacity and reduces the ability of high-level processes to organize inhibition on lower-level processes, to resist temptation (Baumeister et al., 2011; Tiffany, 1990). The individual is particularly vulnerable to capture by salient cues. For some, a negative mood increases the tendency to take sexual risks, experienced as a feeling ‘in this state I don’t care about what happens’ (Janssen and Bancroft, 2007). As Baumeister et al. (2011, p. 349) express it: ‘cognitive load seems to release automatic impulses to dictate actions that conscious reflection would veto’.

  Development

  The evolutionarily new brain processes that underlie high-level control are the last part of the brain to mature, whereas those acting at a lower level mature at a younger age (Chapters 2 and 13). This means that the levels get out of synchrony and the capacity of adolescents to exert high-level control is weak relative to that of adults. Consequently, adolescents have a relatively high tendency to engage in risky activities, such as drug-taking, dangerous driving and unprotected sex. It can be speculated that young children have even weaker restraint processes but there is relatively little to restrain since the low-level systems have not yet fully matured.

  The tendency for stress to shift the weight of control to a low level appears to be greater in those with a traumatic early development, which more usually compromises high-level control (Schore, 2003).

  Chemicals

  Certain chemicals alter the weight of control between high and low levels. Alcohol decreases the influence of high-level controls and thereby increases that of the low level. It triggers what is known as ‘alcohol myopia’, a tendency to bias the focus of attention on the immediate environment (Steele and Josephs, 1990) and thereby short-term goals. This expression is by analogy with visual myopia, where near things are brought into focus at the expense of more distant things. In other words, alcohol increases the salience of physically present stimuli relative to what is held only in memory (Abbey et al., 2006). It lowers sexual inhibitions that are based upon long-term goals (Chapter 15).

  Brain damage

  The more recently evolved brain regions that give human behaviour its flexibility tend to be those most vulnerable to damage. In some cases, damage is associated with a lifting of restraint on behaviour, so that the person engages in behaviour that otherwise would have been inhibited (Luria, 1966). Examples of this include the appearance of paedophilia and explicit unwanted sexual advances to family members.

  What could stress, alcohol and brain damage have in common such that they tend to shift the weight of control from long-term goals to short-term goals (Hofmann et al., 2009)? Each seems to impair the ability of memories drawn with effort from storage to be held online in such a way as to inhibit the actions of the short-term system. When the high-level system is compromised, as in specific brain damage, excessive alcohol or drug use or stress, 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.

  Fixed and flexible brains: link to evolutionary psychology

  What does evolutionary psychology claim?

  Evolutionary psychology is concerned primarily with the function served by behaviour. Its followers suggest the existence of so-called ‘modules’: information-processing units, each of which controls one particular mental operation or bit of behaviour (Tooby and Cosmides, 1990). Such modules have, it is argued, been tested in evolution, since they were found to solve one particular problem that facilitated successful transmission of genes. So, for example, there is a jealousy module, which is activated by any threat of sexual infidelity. It is specialized to solve just this one problem. Because an individual has a module primed to react to threats posed by infidelity, compromises to his or her reproductive success have been reduced. Evolutionary psychologists compare their modules to the organs of the body. There is no such thing as a ‘general-purpose organ’. Each organ is dedicated to serve a particular function, exemplified by the heart’s function of pumping blood around the body.

  A broader evolutionary psychology

  How are the idiosyncratic dimensions of, for example, human sexual desire to be assimilated into an evolutionary perspective? An understanding of brains can be integrated with the notion of modules to yield a convincing evolutionary psychology of sexual desire. It is necessary to consider the idiosyncrasy and flexibility of behaviour that is the hallmark of humans, as well as modularity.

  Fixed and flexible processes co-exist

  Automatic processing appears to map rather well onto evolutionary psychology’s ‘modules’. The system that automatically triggers genital arousal in response to a sexual stimulus seems like a module (Spiering and Everaerd, 2006). The reaction happens fast, at first at a non-conscious level and the system serves this one specialized and dedicated role in the life of humans. However, such modules co-exist with brain processes offering the possibility of flexibility and creativity.

  This evolutionary consideration can be wedded to an understanding of multipl
e (‘layered’) controls of behaviour and their embodiment in the human brain. MacDonald (2008) uses the expression ‘effortful control’ to describe the conscious (‘explicit’) process that acts to control flexible behaviour, sometimes in opposition to the pull of modules. Such processes make a conscious assessment of the likely benefits and costs of an action, albeit an assessment that is often wrong.

  Effortful control is associated with working memory and executive function, embodied in regions of the prefrontal cortex. The exertion of effortful control is a ‘resource-limited function’, meaning that it shows fatigue with use. Individual differences in effortful control correlate with the personality dimension of conscientiousness. People high on conscientiousness have a high capacity for effortful control and are able to curb short-term pleasure-seeking. MacDonald notes that a number of theorists have suggested that adolescent reward-seeking and risk-taking (described earlier) are due in part to the relative development of approach mechanisms coupled with underdevelopment of prefrontal restraint processes. This imbalance is more marked in boys than in girls.

  MacDonald discusses the result that viewing erotic films activates a number of brain regions such as the amygdala. However, viewing them with the instruction to decrease sexual arousal activates regions of the prefrontal cortex but not the amygdala. He notes (2008, p. 1021) ‘This study is particularly interesting because the amygdala response to erotic films is an evolutionarily prepared reaction.’