Sex, Drugs and Chocolate: The Science of Pleasure. Paul Martin

with friends and family, although many men put sex in first place.² The average person reported having sex seven times a month, with a small minority claiming a monthly tally of more than twenty. Nine out of ten people said they found sex more pleasurable with a longstanding partner (not to be confused with a long, standing partner). A common theme to emerge from studies of human sexuality is that many people say they would prefer to have sex more often than they do. The ideal frequency is usually higher for men than for women.

      Pleasure begets pleasure, when it comes to sex. The enjoyment of sex creates a virtuous circle, in which good sex improves mood and good mood in turn gives rise to more sex. This mutually reinforcing relationship was highlighted by a study in which researchers tracked the sexual behaviour of middle-aged women. The results showed that when a woman had good sex with her partner she was more likely to be in a good mood the following day. Being in a good mood made her, in turn, more likely to have sex the day after that.

      Low mood usually dampens sexual desire, although it can have the opposite effect on some individuals. Research has found that a significant minority of men become more interested in sex when they are depressed, anxious or stressed. This may be because they have unconsciously learned to use sex as a form of self-medication, exploiting its combination of pleasure, intimacy, distraction and relaxation to lift their mood. In women, a correlation has been found between low mood and a greater desire to masturbate.

      The lure of sexual pleasure is so powerful that people will find ways of obtaining it even in difficult situations like prisons. Pleasure can also be derived from fantasising about sex. Almost everyone has erotic fantasies, often while they are having real sex. Perhaps surprisingly, research has revealed that men’s sexual fantasies tend to focus more on the desire and pleasure of their partner than do women’s fantasies.

      The sheer diversity of human sexual behaviour is impressive, even for an intelligent ape. Small but significant minorities of humanity engage in a wide range of practices such as sadomasochism and bondage. Some individuals develop a fetish, in which their sexual pleasure becomes linked to an inanimate object which would not commonly be regarded as erotic. Among the many such fetish objects recorded in the psychosexual literature are feet, fire, clothes, rubber, shoes and spectacles. Transvestic fetishists are sexually aroused by cross-dressing. Researchers in Sweden found that almost 3 per cent of men had experienced this form of erotic pleasure at least once.

      Far more people enjoy anal sexuality in its many different forms. The fact that humans and other animals find anal stimulation pleasurable is unsurprising: the anus and rectum are richly endowed with nerve endings, making them highly sensitive to stimulation. Moreover, the genital and anal regions share some of the same nerve connections to the brain, creating the possibility of ‘cross-talk’ between pleasurable sensations originating from either region. Humans have always responded to this aspect of their architecture. Anal intercourse and other forms of anal stimulation are, and always have been, commonplace among heterosexuals and homosexuals. Research in the USA and Sweden shows that between a quarter and half of adults have tried anal intercourse and a small but substantial minority practise it regularly. The use of enemas for sexual pleasure, a practice known as klismaphilia, is also more common than might be assumed. Very few forms of behaviour are unique to humans, and anal sexuality is not one of them. For example, male rhesus monkeys have been observed to have penetrative anal sex with other males.

      The diversity of human sexuality may be remarkable but it is certainly not new. Historical records show, for example, that the ancient Egyptians explored every known variation in the sexual repertoire, including masturbation, anal sex, male and female homosexuality, exhibitionism, incest, bestiality and necrophilia. The Romans were also great sexual explorers. They used a bewildering range of aphrodisiacs to boost their libidos, including bone marrow and cuttlefish. Sex in pre-Christian Rome seems to have been a pleasurable and largely guilt-free form of recreation, in an era when there was no expectation that marriage must be strictly monogamous. Attitudes were much the same elsewhere in the ancient world. Herodotus, who wrote his epic Histories in the fifth century BC, recorded these observations on the sexual practices of tribes inhabiting the lands east of the Mediterranean:

      When a Nasamonian man gets married, it is the custom first for the bride to have sex with all the guests, one after another, on her wedding night; every man she has sex with gives her something he has brought with him from his house as a gift.… Gindanes women each wear many leather anklets; it is said that they tie on an anklet for each man they have had sex with. The woman with the largest number of anklets is considered to be the most outstanding because she has been loved by the largest number of men.

      Recreational sex for its own sake later came to be regarded with severe disapproval, as religious belief clashed with hedonism. We shall return to this theme in chapter 13.

      The dazzling variety of sexual pleasures available to our species has been augmented by the application of technology and pharmacology. The use of psychoactive drugs to enhance sexual pleasure is an ancient tradition. Many different drugs, including alcohol, cannabis, amphetamine, amyl nitrite, ecstasy and cocaine, are said by some users to enhance sex, although the evidence is mixed. The actor Errol Flynn, of whom more later, liked to apply a pinch of cocaine to the tip of his penis. Mechanical technology also has its place, with vibrators and other sex toys forming the basis of a large global industry. A national survey in the UK found that almost half the respondents had used sex toys to enhance the pleasure of sex and one in six had taken drugs for the same reason.

      The vibrator was invented in the late nineteenth century by a British doctor named Joseph Mortimer Granville. He had been searching for a better way to treat ‘hysteria’ – the quasi-medical term that was applied then to what we would now regard as suppressed female sexuality. A common remedy for hysteria at the time was for the doctor to massage the woman’s genitals until she experienced a ‘hysterical paroxysm’, or what we would now recognise as an orgasm. This practice, which was known as ‘medical massage’, had been used by doctors since the time of Hippocrates to give relief to female patients. Administering a ‘medical massage’ could be tiring work for the doctor, and Granville was keen to find a modern, technological way of speeding it up. In 1883 he published a book entitled Nerve-Vibration and Excitation as Agents in the Treatment of Functional Disorder and Organic Disease, in which he described the use of his new ‘Percuteur’ electrotherapeutic device. It was the original vibrator.

      Within a few years, cheap electromechanical vibrators were being widely advertised to the general public. Their ostensible purpose was the relief of muscle pains, headaches, poor circulation, wrinkles, or indeed almost anything that had no explicit link to sex or pleasure. By the 1920s, however, the public connection had been made between vibrators and sexual pleasure, with the result that they rapidly became shameful and virtually disappeared from view until the second half of the twentieth century.

      The use of penis-shaped sex toys to enhance sexual pleasure has a very long history. The antiquities section of any good national museum should contain at least a few artefacts decorated with images of dildos. References to dildos can also be found in the literature of ancient Greece; for example, the anti-war comedy Lysistrata, written by Aristophanes around 411 BC, contains a scene in which Lysistrata and her women friends complain that their husbands are always away fighting wars, leaving them feeling sexually frustrated:

      And not so much as the shadow of a lover! Since the day the Milesians betrayed us, I have never once seen even an eight-inch dildo to be a leathern consolation to us poor widows.

      The ‘Milesians’ were the inhabitants of Miletus in Asia Minor; they were renowned in Aristophanes’ day for manufacturing a tip-top type of leather-covered dildo known as an olisbos, which was used with olive oil as a lubricant. Two thousand years later, William Shakespeare made this thinly veiled reference to the sexual function of dildos in The Winter’s Tale:

      He hath songs for man or woman, of all sizes; no milliner can so fit his customers with gloves: he has the prettiest love-songs for maids; so without bawdry, which is strange; with such delicate burdens of dildos and fadings, ‘jump her and thump her’.

      The innocent reader could choose to