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Pleasure Seeking |
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Is normal and natural |
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| Feeling pretty? Hormones may lead to
more... Women with high levels of estrogen not only look and feel prettier -- but they may act on those feelings by moving from man to man, U.S. researchers reported on Tuesday. Wed Jan 14 WASHINGTON (Reuters) Estrogen, the so-called female hormone, affects fertility and has been shown to make women dress more provocatively and show more thrill-seeking behavior. Dr. Kristina Durante of The University of Texas at Austin and colleagues found that young women felt more attractive when they had high levels of an estrogen known as estradiol, and they acted on those feelings. "Women with higher estradiol reported a greater likelihood of flirting, kissing and having a serious affair with someone other than their primary partner and were marginally more likely to date another man," Durante's team wrote in the Royal Society Journal Biology Letters. "Results provide support for the relationship between physical beauty and fertility and suggest that women high in reproductive health engage in opportunistic serial monogamy -- being open to affairs and moving on to a new relationship if a higher-quality mate becomes available." Durante's team tested 52 female undergraduates aged 17 to 30 who were not taking hormone contraceptives. They took two estradiol samples from each, as hormone levels fluctuate from week to week. They had the women rate their own attractiveness and showed their photographs to others to rate, as well. "High-estradiol women were considered significantly more physically attractive by themselves and others," Durante and colleagues wrote. The high-estrogen women also reported more sexual behavior -- especially outside of a relationship, although it was not linked to one-night stands. "Our results are consistent with the possibility that highly fertile women are not easily satisfied by their long-term partners and are especially motivated to become acquainted with other, presumably more desirable, men," they concluded. The findings fit in with many other studies showing that hormones influence the behavior and success of both men and women. Earlier this week, U.S. and British researchers showed that male financial traders whose finger lengths indicate high testosterone levels in the womb made more money. |
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| Faithful love birds? No, swans like to go
wandering They are symbols of enduring love, immortalised in story, song and poetry. Everyone knows that swans mate for life, staying faithfully together until one dies. Or do they? RICHARD SHEARS Daily Mail 9 June 2006 The heart-warming image of the love birds has been shattered by veterinary researchers who say they are nothing more than feathered philanderers. Males in particular enjoy flitting from one nest to another for trysts with a string of females. The findings come from a study of a group of black swans which live on the Albert Park lake in Melbourne, Australia. And the initial results have shown that a clutch of newly-hatched cygnets can have as many as three fathers. Zoology lecturer Dr Raoul Mulder, who is leading the Melbourne University research, said: "Swans, it seems, like humans, fall a bit short of that idea of lifelong fidelity." 'Playboy males' The playboy male swans have been found out after DNA tests were carried out on a number of cygnets. It was found that one in six had a 'surprise' father. But what the researchers want to find out as they continue their 100,000 study is just when the male swans go out on the prowl - and why their 'spouses' do not seem to have found out. The obvious answer to the last question, the researchers agree, is that the spouses themselves are being unfaithful. Now, to establish just who is doing what to whom and when, every one of the 150 swans on the lake is being fitted with an 'e-tag' on the tail - a movement detector for the male and a receptor for the female. "When the birds copulate, the little back pack on the female will register which male has approached," said Dr Mulder. "We think both parties are guilty as charged," he added. "But if they're doing it, it must be for some good evolutionary reason, such as gaining superior genes for their offspring." Promiscuous While the Melbourne research centres on the black swans of the lake, the scientists point out that the more common white swan - which is found in English waters - is equally promiscuous. But the commonly held view of the birds as inseparable pairs will take some shaking. Even Shakespeare was inspired by what he believed to be the life-long devotion of one swan to another. In As You Like It, he wrote: "And wheresoever we went, like Juno's swans Still we went coupled and inseparable." History repeats, time and again, the bonding between a male swan his mate. "The cob (male swan) will lay down his life for his family," one poetic writer noted. "If one of the pair dies, the other often lives out the rest of his or her life alone. The love and loyalty of these beautiful birds has inspired legends for centuries." Even on-line dating services are cashing in on the accepted love and devotion of the swan. A US-based matching company calls itself White Swan Love and promises to bring "white swan girls" and "white swan men" together in the same nest. But based on what the Melbourne researchers are finding out, such newly-matched couples might find it worth keeping a careful eye on one another. |
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| Being a sex addict is in your genes
Some people simply can't help being 'sex addicts', according to a new discovery by scientists. Daily Mail 26 May 2006 They have found that people with a certain genetic make-up have a much stronger sex drive than others. The remarkable finding could go some way to explaining the behaviour of self-confessed 'sex addicts' such as Michael Douglas. It could also help provide reassurance for those who are perfectly happy with their relatively low libido, but are made to think they are abnormal because magazines, television and films suggest most people having sex all the time. The new research centres on a gene called D4, which is involved in the brain's reaction to the pleasure chemical dopamine. Tests on animals have suggested this gene may influence sex drive and arousal. A team from Hebrew University and Ben Gurion University of the Negev in Israel tested the DNA of 148 male and female students to find variations in the gene. The students were also asked to complete a questionnaire to assess their sex drive. It included questions such as whether they felt aroused when they saw a steamy scene in a film, how often they made love and the frequency that they thought about sex. It emerged that generally men thought about sex more often than women, however overall both genders experience similar levels of arousal. But when the scientists looked at the different genetic make up of the students, an interesting trend emerged. People with one particular variation of the D4 gene - around 30 per cent of those studied - had a stronger sex drive than the others. Lead researcher Professor Richard Ebstein of Hebrew University said the study is the first to identify a specific gene variation linked to sex drive. "Some people really do think more about sex and place a greater importance on it than others and what our study suggests is that genes may make a substantial contribution to these differences," he said. He said the findings may also help explain why some people are sex addicts. Prof Ebstein said past studies have shown the chemical produced by the D4 gene is linked to addictive behaviour such as gambling. However he added that D4 would not entirely account for sex addiction, as other genes and social factors may also play a part. Hollywood star Michael Douglas famously checked into an Arizona clinic to be treated for sex addiction during his marriage to his first wife Diandra. Given his past, his second wife Catherine Zeta Jones had it written into their pre-nuptial agreement that if they divorced she would get 1.7 million for each infidelity she found out about. His father Kirk Douglas also admitted to being a womaniser. His first wife divorced him after he said he could not remain faithful and his second wife agreed to turn a blind eye to his 'chance encounters'. Halle Berry's ex-husband Eric Benet is also reported to have checked into a clinic to help him overcome his sex addiction. Prof Ebstein hopes his study will open up new ways to tackle and treat sexual problems. At the same time, it may also provide reassurance for many. "If you have a lower sex drive, it does not necessarily mean you should go to see a sex therapist to see if something is wrong with you,' he said. "As long as it is not causing a problem in your life, may be you don't have a problem. If it does not bother you or interfere with your life, then maybe you are best to just live with it. "After all, if you are not good at music, you don't keep on trying to play the saxophone." |
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| The new pleasure seekers Ian Sample talks to the scientists teasing out why we strive so much for pleasurable experiences - and why, when we have it all, we risk everything for more excitement Thursday December 16 2004 The Guardian For as long as they have existed, students have embraced the role of obliging guinea-pigs, on hand to take part in all manner of intrusive, humiliating and bizarre experiments dreamed up by their supervisors. Nonetheless, one of Michel Cabanac's experiments must have raised eyebrows. "I offered them money to feel pain," says the physiologist at Laval University in Quebec. "It can be quite dangerous, because what if a student has just destroyed his parents' car? He's going to need money really badly." Undeterred, Cabanac lined his students up against a wall. It was going to be bad, but not as bad as they might have thought. He got them to sit, as if perched on an imaginary stool, a position which forced their weight onto their knees. "Try it," he says. "The pain soon becomes unsufferable." Cabanac then promised the students increasingly large lumps of cash to endure the pain. The more he offered, the longer they suffered. The longest lasted for eight minutes 20 seconds. Ironically, Cabanac's experiment was part of a broader investigation into the science of pleasure. His aim was to find out what, if anything, was the point of pleasure. His conclusions, and those of other scientists working in the field, suggest that not only is pleasure good for our health, but it is at the root of our ability to make sense of the complex world in which we live. Cabanac's proof that people will suffer pain for payment will come as no surprise to the millions who do things they hate in return for a monthly pay cheque. But in a follow-up experiment, Cabanac showed there was a more fundamental point to make about what influences our behaviour. Before the second test, Cabanac asked people to rate the pleasure they got from playing a video game. They were then sat in a temperature-controlled room and Cabanac, while cooling it down, asked them to rate how unpleasant the feeling was. He then combined the two experiments. "We cooled the room down, and every time, the same thing happened. As soon as it was cold enough for their displeasure rating to just outweigh the pleasure of playing the game, they stopped the experiment," he says. According to Cabanac, the tests show that, while it might not be obvious all the time, each of our decisions is ultimately driven by pleasure-seeking. "Pleasure is the common currency that allows us to make any, and I mean any, decision in our lives," he says. "Any decision is made according to the trend to maximise pleasure." Pleasure-seeking certainly makes evolutionary sense. As organisms developed, the emergence of pleasure as a sensation will have helped reinforce healthy behaviour, such as eating certain foods, having sex and keeping warm. But while Cabanac's theory might make evolutionary sense, that doesn't make it correct. It doesn't take long to think of examples where a decision looks entirely unpleasurable. What about a decision that ultimately leads to a person's own death? How could that choice come out as the most pleasurable path to take? In 1969, Jan Palach, a Czech student, set himself on fire in protest at the Soviet invasion of his country. He died from his injuries three days later. "That's an atrocious death, yet he did it by choice," says Cabanac, who assumes Palach was not mentally ill. "The fact that he was suffering hell by dying by fire was compensated by an overwhelming joy of telling the Russians 'Look. Look what we are able to do against you. You do not win.'" At the Neurosciences Research Institute at the State University of New York, director George Stefano believes that pleasure is not only the driver for every decision we make, but is a crucial component for making sense of the world. "As human beings, we always pride ourselves in being rational, but if we were 100% rational, we would have to weigh up every single possible action we might take at any time. Imagine how time-consuming that would be. Even a cognitive organism doesn't have time to be truly rational," he says. Pleasure, says Stefano, is our brain's way of short-cutting the rational process by subconsciously and continuously ranking what is most important to us from the vast number of options we are faced with. Stefano's phrase for it is likely to make dedicated hedonists smile: "Pleasure leads to pure rationality," he says. As with the majority of neuroscience, some of the most reliable evidence comes from studying people who were born with, or have later suffered, damage to specific parts of the brain. At the University of Iowa, a team lead by neuroscientist Hanna Damasio has been studying people with lesions in a region of the cortex associated with pleasure. They found that although the patients had no intellectual impairment, in a simple gambling test, they made hopeless decisions. "They are oblivious to the consequences of their actions," the team noted in a paper published in the journal, Brain. Despite decades of effort, scientists are still teasing out the precise neural circuitry that allows us to experience pleasure. In the 1980s, many scientists believed there was just one major brain circuit that governed pleasure. Triggered by the neurochemical dopamine, it excited the cerebral cortex and other areas of the brain such as the amygdala and nucleus accumbens. But more recent research has cast doubt on the role of dopamine. It now seems the chemical plays a subtly different role - making us feel desire rather than pleasure. Scientists now know that another brain circuit, triggered by chemicals called opiods, does play a key role in pleasure sensations. Injecting drops of opiod into a part of the brain called the ventral pallidum heightens the enjoyment of sweet tastes, they found, suggesting it boosts the natural pleasure sensation. Meanwhile, at Oxford University, a team lead by neuroscientist Edmund Rolls has discovered that a region of the brain called the orbitofrontal cortex (OFC), which lies just behind the eyes, contains bundles of cells that are triggered by different types of pleasurable experience. Signals from the OFC are then thought to feed into the dopamine and opiod circuitry. According to Cabanac, pleasure can only be a transient sensation, the feeling of warming up when cold, or of eating when hungry. He believes that the lack of these gaps between how we feel and how we want to feel explains a lot of misery in modern society. "We're not hungry, we're not cold, we have everything," he says. The result, he says, is that we are tempted to seek pleasure in other ways, by taking drugs, or over-indulging in pleasurable activities. Extremely hedonistic lifestyles may be caused by compulsive behaviour leading to an endless craving for pleasurable sensations, or subtle damage to the underlying brain circuitry, he adds. Of course, it's possible to have too much of a good thing, and pleasure can easily become pain. This flipping of pleasure into pain has been investigated using brain scans focusing on the OFC and have captured the fine line that is the difference between the two states. Marilyn Jones-Gotman of the Montreal Neurological Institute at McGill University recruited self-confessed chocoholics and fed them lumps of chocolate while monitoring their brain activity using a brain-scanning technique called positron emission tomography. After each chunk, the person was asked to rate how much they wanted another piece. "We fed them until they absolutely could not face another bite," she says. Jones-Gotman found that as the experience of eating chocolate flipped from being intensely pleasurable to downright repulsive, activity in the orbitofrontal cortex shifted from the centre to nearer the outside. They had captured the exact point where pleasure became pain. But is this the change that tells us when we've had too much of a good thing? Jones-Gotman doesn't think so. "If you're over-eating, expecially in cases like Christmas dinner when you're eating food that people like very much and associate it with the good feeling of previous Christmases, you probably won't stop until it's actually painful," she says. While pleasure may have evolved as a way to encourage creatures to indulge in healthy behaviour and avoid more harmful pursuits, Stefano believes there is another benefit. Inside brain neurons, and also other tissues in the body, is a chemical called proenkephalin. He says that when we experience pleasure, proenkephalin is broken down, producing a substance that causes a feel good sensation. But the same enzymes involved in that process also release another chemical called enketylin, a strong antibacterial agent. "Just think of the beauty of that: when you're feeling good, you protect yourself," says Stefano. Though scientists are slowly teasing out the secrets of pleasure, they have a long way to go. One problem is that little funding goes into looking at why things go right in humans. Instead, money pours into researching disease and disorders. "It's time that changed a little," says Stefano. "Feeling good is healthy. Why don't we look into it?" Further reading www.nel.edu/25_4/NEL250404R01_Esch-Stefano_v4_2p.pdf The neurobiology of pleasure and its effects on health http://wings.buffalo.edu/aru/ARUreport01.htm A review of pleasure systems in the brain www.thebrain.mcgill.ca Graphics of the brain and neural circuitry Affective Neuroscience: The foundations of human and animal emotions, Jaak Panksepp, OUP, 2004 Descartes' Error: Emotion, reason, and the human brain, Antonio Damasio, OUP, 1994 |
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