A class of nerve fibres in the skin that specifically transmit pleasure messages to the brain have been identified by U.S. and Swedish boffins, who say their finding could improve understanding of how touch sustains human relationships.

For many years, Scientists have been trying to understand the mechanisms behind how the body experiences pain, and the nerves involved in conveying those messages to the brain. Because, in conditions like Neuropathy, where the peripheral nervous system is damaged, people can suffer a great deal after the messaging system has gone wrong, and feel pain even when there is no cause.

Professor Francis McGlone, the author of the study said:

If you get a piece of grit in your eye, have a toothache, or bite your tongue, it hurts so much because there are more C fibres there. The research we have been doing is building evidence for another role of C fibres in the skin that are not pain receptors, but pleasure receptors.

In this research, published in the journal Nature Neuroscience, experts from the University of Gothenburg in Sweden and the University of North Carolina, including scientists from the company Unilever, identified “C-tactile” nerve fibres, which sent pleasure messages to the brain.

Then the scientists used a “robotic tactile stimulator” – basically, a computerized mechanical arm fitted with a soft brush – on twenty volunteers, to determine the speed at which C-fibres should be touched to activate the pleasure sensation.

It was observed that if the rate of being rubbed was faster or slower than an optimum speed of four to five centimetres per second, then the nerve fibres weren’t activated, and the touch wasn’t pleasurable. They also discovered that C-tactile fibres are only present on hairy skin and are absent in the palm of the hand.

Professor McGlone said these nerve fibres are part of the evolutionary mechanism that helps humans bond. People preferred being fondled in a manner similar to the one used by a mother to comfort a baby or by couples when demonstrating love.

He continued:

We believe this could be Mother Nature’s way of ensuring that mixed messages are not sent to the brain when it is in use as a functional tool. Our primary impulse as humans is procreation, but there are some mechanisms in place that are associated with behaviour and reward which are there to ensure relationships continue.

Posted by Jonathan as Biology, Sociobiology at 9:10 PM BST

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Researchers have confirmed that male Chimpanzees that are willing to share the proceeds of their hunting expeditions with females mate twice as often as counterparts who prefer to keep their food to themselves.

Cristina Gomes and her colleagues, from the Max Planck Institute for Evolutionary Anthropology in Germany, studied chimps in the Tai National Park, Cote d’Ivoire, West Africa, and found that more generous Chimps had sex more often.

These findings are significant because they’re long-term arrangements, whereby males will share meat from hunting expeditions with females even when they’re not in oestrus – thereby increasing the possibility of having sex when the same females are in oestrus.

How females choose their mating partners and why males hunt and share meat with them are questions that have long puzzled scientists. The “meat for sex hypothesis” had already been proposed to explain why male chimps might share with females, but previous attempts to observe the phenomenon had failed, because previous researchers had only looked for direct exchanges where a male shared meat with a fertile female and copulated with her straight away.

Dr Gomes said:

Previous studies might not have found a relationship between mating success and meat sharing because they focused on short-term exchanges; or perhaps because in those groups access to females was driven by male coercion so females rarely chose their mating partners.

The researchers therefore took a different approach, reasoning that previous studies had found that grooming exchanges (where the animals take it in turns to groom each other) happen over long periods, so they theorized, why not meat and sex?

Dr Gomes and co-author Christophe Boesch collected data from 262 male to female meat transfers (the meat was mostly that of Red Colobus monkeys), and 262 matings during times when females were in oestrous. The scientists noted that males would share with all types of females, whether in oestrous or not, although the former received preference.

Dr Gomes said:

We looked at chimps when they were not in oestrus. The males still share with them – they might share meat with a female one day, and only copulate with her a day or two later.

By sharing, the males increase the number of times they mate, and the females increase their intake of calories. What’s amazing is that if a male shares with a particular female, he doubles the number of times he copulates with her, which is likely to increase the probability of fertilising that female.

It’s also suspected the same may hold true for hunter-gatherer humans, since earlier studies suggest that men who are more successful hunters tend to have more sexual partners and a larger number of offspring.

Dr Gomes suggested her team’s findings could offer clues about human evolution. And indeed, the teams report states:

Similar studies on humans will determine if the direct nutritional benefits that women receive from hunters in foraging societies could also be driving the relationship between reproductive success and good hunting skills.

The team describe their findings in the journal PLoS One.

Posted by Jonathan as Anthropology, Sociobiology at 12:27 AM BST

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Feminists would certainly claim it was obvious that men perceive sexy women in bathing suits as objects, but now there’s some science to back this theory up.

New research shows that, in men, the brain areas associated with handling tools and the intention to perform actions light up when viewing images of women in bikinis, suggesting that sexy images can shift the way men perceive women, turning them from people to interact with, to objects to act upon.

The research was presented this week by Susan Fiske, Professor of Psychology at Princeton University, at the annual meeting of the American Association for the Advancement of Science.

Professor Fiske said:

This is just the first study which was focused on the idea that men of a certain age view sex as a highly desirable goal, and if you present them with a provocative woman, then that will tend to prime goal-related responses.

The study focused on a region of the brain just above the eyes, called the medial pre-frontal cortex, which, when activated seems to damp male tendencies to express hostile sexist thoughts about women.

Professor Fiske continued:

Men who express the strongest sexist tendencies tend to have a less active medial cortex. It becomes deactivated in men who are the most hostile to women, but only for women in bikinis.

So basically they are particularly likely to treat these women as objects, at least that is the interpretation of the data we have so far. It is a preliminary study but it is consistent with the idea that they are responding to these photographs as if they were responding to objects rather than people.

It was shocking to find that the pictures of scantily clad women deactivate the medial pre-frontal cortex. The only other time we’ve observed the deactivation of this region is when people look at pictures of homeless people and drug addicts who they really don’t want to think about what’s in their minds because they are put off by them.

The participants, twenty-one heterosexual male undergraduates at Princeton University, first took questionnaires to determine whether they harbour “benevolent” sexism, which would include the belief that a woman’s place is in the home, or “hostile” sexism, a more adversarial viewpoint which includes the belief that women attempt to dominate men.

The volunteers were then placed in a fMRI brain scanner whilst viewing a set of images of women in bikinis, women in clothes and men in various types of clothes. The scientists also used “sexualised” images, where the head of each semi-naked photograph was digitally removed, so that only the torso was visible. The men were given memory tests afterwards, concerning what they had remembered about each image, with and without the heads.

The results showed that men had the best memory for the sexualised bodies of women (the ones with the heads digitally removed) even though they had only seen the bodies for 200 milliseconds. In the men who scored highest on “hostile” sexism, the part of the brain associated with analyzing another person’s thoughts, feelings and intentions shut down while viewing the scantily clad women.

A supplementary study of both male and female undergraduates found that men tend to associate bikini-clad women with first-person action verbs such as I “push,” “handle” and “grab” instead of the third-person forms, such as she “pushes,” “handles” and “grabs.” On the other hand, men associated fully clothed women with third-person forms, indicating that these women were perceived as being in control of their own actions. The females who took the test did not show this effect.

Professor Fiske said:

The broader purpose of the research was to explore circumstances under which people treat one another as the means to an end.

Taken together, the research suggests that viewing certain images is not appropriate in the workplace; when there are sexualised images in the workplace, it’s hard for people not to think about their female colleagues in those terms. It spills over from the images to the workplace.

I’m not advocating censorship, but people need to be aware of the associations people will have in their minds.

Women may also depersonalize men in certain situations, but published research on the subject has not been carried out, experts say. But, Evolutionary Psychology would theorize that men view women as objects in terms of their youth and apparent fertility, while women might view men as instrumental in terms of their status and resources, Fiske noted.

Posted by Jonathan as Anthropology, Sociobiology at 10:14 PM GMT

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Type the word “Seduction” into any Search engine, and you’ll be met with a plethora of results for videos, e-books and courses, all claiming to help you “Meet that one special girl“, “Win back a lost love” or “Attract any woman“.

Much of this advice is commonsense but obvious, and should therefore be free of charge (i.e. dress smartly, be clean and smell nice), some is practical but vastly overpriced (i.e. be more confident, and go out more often), whilst some is completely absurd, and evidently aimed at extracting as much money as possible from naïve people, before they realise they’ve been cheated by a Charlatan (i.e. Psychic influence, Cosmic ordering and pretty much anything that mentions ‘Energy’).

So, maybe you’re looking for that special Seduction ‘Secret sauce‘, and are hoping to attract women. Well, I’m afraid it’s bad news my friend, you can’t attract any woman, neither can I, and anyone else who claims to be able to is a liar!

Now, you may have seen Spamvertisements claiming that you can start a successful business overnight; but you didn’t reply to them because you knew they were Multi-level marketing or a front for an illegal scam. Similarly, there’s no secret way to become a champion Sportsperson overnight; and the same argument could be levelled at all other purported Miracle cures and Get rich quick schemes.

Just think about this for a second: If there really was some ‘secret sauce‘, Multi-Billion dollar companies and top athletes wouldn’t need to invest any time or effort building up a reputation, getting in shape and clawing their way to the top of their chosen niche. Everyone could just buy whatever Magic bullet was advertised, and instantly become richer than Bill Gates and more successful than Muhammad Ali, all without a stroke of effort. It’s a delicious thought, but clearly a fantasy.

Seduction, however, is just half as bad; since it’s only women who can attract men - simply by dressing in revealing clothing and looking pretty. But, this passive approach doesn’t work for men – who need to be more active, and to manipulate the woman of their desire into choosing them as a sexual partner, via various seductive methods.

All of this has its roots in Evolutionary theory and Sociobiology, which helps to answer the bizarre paradox of why large numbers of men should find it highly arousing to look at visual images of naked women – it doesn’t matter whether these are paintings, photographs, pixels or a real person; intellectually, most men are not morons, and know that arousing images are just that – images - however, the basic male inclination is to have an especially low threshold for sexual stimulation.

Various theories have been put forward to explain this paradox, including eyesight having evolved differently in the sex responsible for hunting in hunter-gatherer societies, through simpler explanations such as seeing people having sex likely means that you too will be having sex shortly.

In other mammals, female reproductive value is revealed primarily by the presence or absence of oestrus; that is to say, by advertising ovulation. But, human females do not advertise ovulation; and thus natural selection seems to have favoured a male’s ability to “assess” reproductive value largely through visual cues.

What we know with more certainty is that because a man can potentially impregnate a female at almost no cost to himself in terms of time and energy, natural selection has favoured the basic male tendency to become sexually aroused by the sight of naked females, with the strength of arousal being proportionate to perceived female reproductive value. Thus, for a male, any random mating may pay off reproductively, and even if he fails, he has lost proportionately very little.

Human females, on the other hand, invest a substantial amount of energy and incur immensely greater risks by becoming pregnant; hence the circumstances of impregnation are extremely important to female reproductive success. If a female makes a bad choice and is inseminated by an inferior male (i.e. one whose offspring fail to survive or reproduce), she may spend months pregnant, not to mention lactating once her offspring are born, only to find that her genes have not been passed to future generations, after having expended all that time and energy.

Thus, a nubile female almost never experiences difficulties in finding willing sexual partners, and in nature, nubile females are nearly always found to be with a partner. The basic female “strategy” is therefore to obtain the best possible ‘husband’, and be fertilized by the genetically fittest available male (always, of course, taking risk into account), and to maximize the return on sexual favours bestowed.

To be sexually aroused by the sight of males would promote random intercourse, therefore undermining all of these aims, and also wasting time and energy that might be spent nurturing children, or in economically significant activities. Thus, a female’s reproductive success would be seriously compromised by a tendency to be sexually aroused by the sight of males.

A male’s desire to look at naked women, especially women he hasn’t seen before, and to seek out opportunities to do so, is part of the motivational process that maximizes male reproductive opportunities. There is no corresponding benefit for females in wanting to look at naked men; hence natural selection has not favoured female impulses to become sexually aroused by the sight of naked men or to seek out opportunities to look at them. If females tended to become sexually aroused by the sight of male genitals, men would be able to obtain sexual intercourse simply by displaying their genitals - however, the deliberate display of male genitalia to unfamiliar women is understood to be a sort of threat, whereas a similar female display is understood to be a sexual invitation.

So, why are there so many adverts claiming that men can attract any woman? The answer is simple: Low-intelligence men that no sane employer would ever hire, but who know that sex sells, reason:

I like women that have spent time in the Gym and who use make-up - therefore, women must also like men that have spent time in the Gym and who use make-up.

Thus, through their faulty logic (or possibly even though fraudulent intent in some cases), these men surmise that by selling obvious advice augmented with exaggerated claims about exercising, wearing cosmetics and spending a lot of money on clothes – their pupils will have women falling at their feet - even if these self-styled Seducers themselves have made zero effort to prove the efficacy of their expensive programmes, before promoting them to gullible and lonely adolescents on the Internet.

Posted by Jonathan as Philosophy, Sociobiology at 5:09 AM GMT

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Money might not buy you love, but according to new research, the pleasure that women get from making love is directly linked to the amount of money their partner earns.

The link between sex and money, and the apparent sexual attraction of fabulously wealthy men, has been debated for years, with radical feminists arguing that beautiful women involved rich men were just doing it for the lifestyle – and enduring the sex as a by-product. Whilst the female orgasm has also been the focus of much research because it appears to have no reproductive purpose, and women can become pregnant whatever the level of pleasure they experience during sex.

Now, however, it seems that through an Evolutionary biological explanation, there is mounting evidence that for many women, money has aphrodisiac qualities, as well as purchasing power. Thus, Dr Thomas Pollet and Professor Daniel Nettle, of Newcastle University, used one of the world’s largest studies into lifestyles, to examine the link between wealth and enjoyment of sex – and to determine whether the female orgasm is an evolutionary adaptation that drives women to choose and retain high-quality partners.

The study they used, the Chinese Health and Family Life Survey targeted 5,000 people across China to conduct in-depth interviews about their personal lives, including detailed questions about their sex lives, income, education and other personal details – although only 1,534 respondents had complete answers in each section of the questionnaire. So, only those fully complete responses formed the basis of the study.

The researchers found that 121 of the women reported always orgasming during sex, whilst 408 had orgasms ‘often’. Another 762 ’sometimes’, and 243 orgasmed rarely or never. These figures being broadly similar to those found in western countries.

The study found that various factors influenced the women’s enjoyment of sex. However, the link between enjoyment of sex and partner’s wealth was statistically significant even when they took into account other factors such as age, education, happiness, the length of relationship and health.

Dr Pollet said:

We found that increasing partner income had a highly positive effect on women’s self-reported frequency of orgasm. More desirable mates cause women to experience more orgasms.

While we cannot rule out reporting bias, we note that the interviews took place away from the respondent’s home, without their partner present and with the respondents able to input their responses directly into the computer if they so wished.

This is not an effect limited to Chinese women. Since, previous research in Germany and America has already examined attributes such as body symmetry and attractiveness, finding that these are also linked with orgasm frequency. Money, however, seems to be the main factor.

The Scientists do note that the findings might also be explained by any of three types of bias in the study:

1. Women who have frequent orgasms may tend to overestimate their partner’s income.
2. Women with ‘high powered’ partners could exaggerate how much they enjoy sex.
3. Women who are highly susceptible to orgasms select partners who are wealthy.

This third suggestion could also be interpreted as more desirable mates cause women to experience more orgasms, so if this is true, a woman’s “capacity for orgasm” could have evolved to help her discriminate between males on the basis of their quality.

Thus, the researchers conclude that a wealthy mate equals a more desirable mate and women demonstrate this by being more responsive in bed.

The original paper, which can be seen here, was published in the journal Evolution and Human Behavior.

Posted by Jonathan as Psychology, Sociobiology at 10:07 PM GMT

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Women with high levels of the sex hormone Oestradiol (a form of Oestrogen linked to female fertility and reproductive health) tend to consider themselves more attractive and are often found to be more attractive than women with lower amounts of the sex hormone.

According to Doctoral candidate Kristina Durante and Assistant Professor of Psychology Norm Li, young women who produce naturally high levels of Oestradiol are more likely to have affairs, and to change partners more frequently. They also see themselves as more attractive than other women.

The researchers, from the University of Texas at Austin, suggested that those women engage in “opportunistic serial monogamy” i.e. they are open to flings and moving on to new relationships, if a higher-quality mate becomes available.

Kristina Durante explained:

Physically attractive women receive more male attention and, when in relationships, are more likely to be the targets of mate poaching. Attractive women also have especially high mating standards.

Because it’s difficult to obtain a partner who is a good provider and also has good genes, women often have to trade off between having a long-term mate who provides continual material resources and more physically attractive, short-term sexual partners with good genetic resources.

However, highly attractive women demand greater amounts of both types of resources in a male partner, in addition to good parenting and partner skills. Thus, physically attractive women may not only have more alternatives but also high standards that are difficult to satisfy.

Accordingly, they may have fewer reasons to be committed to any particular partner if higher quality potential mates are available.

Previous research has indicated that Oestradiol, which is similar to Testosterone in men, fuels a lust for power in single women – Although Oestradiol levels rise and fall across a woman’s ovulatory cycle – generally corresponding to fertility and interest in sex.

In their study, Durante and Li investigated the relationship between Oestradiol and sexual motivation, by taking saliva samples from fifty-two normally cycling female undergraduates aged 17 to 30, at two points of their menstrual cycle, in order to establish baseline levels of the hormone, and rule out the effect of monthly fluctuations. They then asked the participants to answer a survey about their sexual history and their propensity to cheat on a partner by flirting, kissing, dating, having sex, or maintaining a serious affair.

Participants were also asked to rate their own physical attractiveness, and an independent panel of two male and seven female observers, unaware of the nature of the research, were used as independent confirmation, to score the subjects physical attractiveness from full-body photos.

The researchers found that a woman’s Oestradiol level was positively associated with self-perceived physical attractiveness, but negatively associated with their satisfaction with their primary partner. Women with a higher Oestradiol level also reported a greater likelihood of flirting, kissing and having a serious affair with someone other than their primary partner. But, they were only marginally more likely to date another man.

However, whilst high-Oestradiol women had significantly more long-term relationships, the hormone was not related to the likelihood of having more one-night stands. Durante stated:

Our findings show that highly fertile women are not easily satisfied by their long-term partners and are motivated to seek out more desirable partners. However, that doesn’t mean they’re more likely to engage in casual sex. Instead, they adopt a strategy of serial monogamy.

Kristina Durante theorized that the behaviour could be an adaptation to the high costs of giving birth, evolved from when women were more dependent on men to support them through childbirth and child-rearing, claiming:

For women it’s all about the resources that we need. If you’re going to be getting knocked up there’s a significant cost

The study “Oestradiol Level and Opportunistic Mating in Women” was published in the Proceedings of the Royal Society of London journal Biology Letters.

Posted by Jonathan as Biochemistry, Sociobiology at 2:39 AM GMT

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Recently, there was much amusement in the labs whilst we watched the consternation unfurl, when Scientist’s announced that after re-examining semen samples taken from Vietnam war veterans, they’d discovered that men with higher IQs have better quality sperm.

The Smarty-pants set took this as confirmation that spending your time studying difficult sums or reading Shakespeare trumps working out and spending your spare time developing bulging biceps; whilst the Muscle boys were up in arms, claiming: Everyone knows a good complexion and nice hair are better than a large IQ. Pretty girls only like Athletes and Bodybuilders – therefore Intellectuals must be destined to die lonely and dateless.

The humorous point is that both camps appear to have confused ‘inclusive fitness‘ of an individual as part of a species with ‘personal fitness‘ such as one might see in a Gym. The downside, we believe, is that this misunderstanding encourages a dangerous myth that Evolutionary fitness is simply a matter of grading masculinity, rather than an expression of the human race’s ability to survive as a species.

People with an understanding of current Evolutionary science will realise that a number of factors feed into ‘inclusive fitness‘, whilst both ‘personal fitness‘ and ‘intelligence’ are simply theoretical optimum conditions – i.e. once one reaches a threshold level of personal fitness and intelligence, then any further advances are a bonus, rather than a guarantee that your genes are markedly better than anyone else’s.

Certainly, some women prefer Bodybuilders, and those Bodybuilders will have an advantage with those women. Just like some women prefer Intellectuals, and those Intellectuals will have an advantage with those women.

Clearly, the person who has trouble catching their breath after running for a bus is certainly at a disadvantage to the rest of the population, whilst the person that can’t work out how to make sense of the Bus timetable is also at a disadvantage to the rest of the population. However, human beings live in an altruistic society, where we usually co-operate to help each other out.

Thus, if I’m not personally fit enough to lift heavy objects all day, I can pay someone to do it for me. Likewise, if I’m not intelligent enough to fix my broken computer, then I can pay someone to do that for me too.

Inclusive fitness and intraspecific competition

Charles Darwin recognized that the interests of individuals are very often synchronized with the interests of their larger groups. As an example, consider the amazing visual acuity of a Hawk, which, at a distance of about a quarter of a mile, can spot a motionless brown mouse in a pile of dry leaves – Eyesight is of paramount importance to hawks, which find food by cruising at great distances above ground level in search of rodents and other small prey.

The fact that hawks see so well is not an accident. The bird’s complex optical hardware and neural software has evolved over millions of generations, in which those Hawks with the best eyesight caught more prey, and hence left more offspring, than their more nearsighted conspecifics. So, the ability to see clearly at long distances is a trait that is advantageous not only to individual Hawks but also to Hawks as a species. Thus, if all hawks had sharper eyesight, the entire species will fare better.

The same is also true of very many other traits and abilities – if all Cheetahs could run a little faster, Cheetahs as a species would fare better, if all Chimps were more intelligent, Chimps as a species would fare better; if all Sharks had a keener sense of smell, Sharks as a species would fare better, etc. etc.

However, there are many other traits and abilities, for which this pattern does not hold.¹ Consider, for instance, the antlers of the male Elk. Natural selection has favoured individual males with larger antlers because the broader an individual male’s rack of antlers the more likely he was to prevail against his rivals for reproductive access to females. Over millions of generations, this advantage led to a gradual increase in the size of Elk antlers, and today the antlers on some males span almost five feet. But, whereas larger antlers help any given male gain advantage over others, they confer no similar advantage for male Elk as a group. In fact, the contrary is true, they are positively harmful.

The reason is that broader antlers make it more difficult for Elk to escape from predators. Once a pack of wolves chases a male Elk with a five foot rack of antlers into the woods, the Elk is trouble. Twist and turn though he might, he simply cannot transport these appendages through trees quickly enough. This is a serious disadvantage, and it might seem that natural selection could not possibly have favoured Elk who were thus encumbered.

Weighing against this disadvantage, however, was the fact that Elk with the broadest antlers had access to more females and, despite their briefer lives, therefore left more offspring. As long as this advantage was more than sufficient to compensate for the increased risk of death from predation, natural selection continued to favour bigger antlers. Eventually however, the advantage from further increases in size no longer outweighed this risk, and from that point antlers grew no further.

The important message of this story is that even though all Elk would clearly do better if every animal’s rack of antlers were trimmed by half, it would not be advantageous for any single animal to trim his antlers. Thus, if a mutant male were born with half-sized antlers, he would be at a hopeless disadvantage in the competition for mates. He might survive to a ripe old age, but in evolution what counts is not how long he lives but the number of grandchildren he leaves; and a mutant with stubby little antlers simply will not leave many grandchildren.

Similar forces appear to explain the exuberant plumage of the Peacock. Drab Peahens favour males with the longest and brightest tail feathers¹. And, experimenters have shown that males with artificially augmented tail feathers are almost always much more successful than other males in acquiring mates. The most common hypothesis for this is that a vibrant tail display is a credible signal that the male is in robust health; a view that is supported by findings that plumage deteriorates sharply in animals with heavy parasite loads.² The logic is that females are likely to have more grandchildren if they mate with males having genes promoting parasite resistance.

In any event, once Peahens came to favour Peacocks with longer tail feathers, natural selection relentlessly began culling males with the shortest displays in each generation, leaving us with modern Peacocks whose tails can reach five feet or more. But like larger antlers on male Elk, longer tail feathers entail costs. They make males not only less able to escape predators but also more likely to attract their attention in the first place. Peacocks as a group would fare much better if each bird’s tail display were shorter by half. Yet, any lone mutant with a shorter tail display would be at a hopeless disadvantage.

Sexual dimorphism (significant sex differences in size within a species) provides another vivid illustration of the conflict between individual and group. Many Bull elephant Seals, for example, weigh over a ton, and can be more than twice as big as their female counterparts. This enormous difference in size was driven by the advantage enjoyed by slightly larger males in their battles with one another for access to females. The victorious males typically command large harems, thereby eliminating a majority of their rivals from the reproductive sweepstakes.

But, whereas size is advantageous in the contest for reproductive access to females, it is disastrous in numerous other ways. It increases caloric requirements, with mature Bulls needing to eat hundreds of pounds of fish each day just to stay alive. It is also disadvantageous in that the victorious breeding males are so large that they sometimes crush their females to death during the act of mounting them. The largest animals may also be more prone to a variety of orthopaedic problems.

As with the evolution of antlers and tail feathers, the advantages of becoming slightly larger eventually came into balance with the disadvantages, and the weight of surviving males stabilized. As before, however, there is nothing attractive about this outcome from the perspective of male Elephant Seals as a group. Each animal would fare much better if all were considerably smaller. The most able fighting males would still gain access to the most females, while most of the disadvantages of excessive size would be avoided. Yet, here too, the problem cannot be solved at the individual level. A smaller mutant would gain the advantages of not needing so much food and not crushing any female he mounted – but these advantages would be swamped by the fact that he would be unlikely to gain access to any females in the first place.

All these examples illustrate Darwin’s central insight that natural selection can, and often does, favour traits that increase the reproductive fitness of individuals at the expense of larger groups. If a trait serves the interests of both individuals and the groups to which they belong, so much the better. But when conflicts arise, individual interests often prevail.

Armed with this insight, modern Behavioural Biologists have begun to make sense of a long list of animal behaviours that are obviously counterproductive at the species level. Thus, in many of the more polygynous species, such as Lions, a successor’s first act on defeating a dominant male is to kill all the young offspring left behind. This practice accelerates the fertility cycle of the lactating females, and thus serves the genetic interests of the conquering male. Yet it is utterly wasteful from the perspective of Lions as a group.

When a dog and his rival each want the same bone, each animal must make a strategic decision in which contextual cues prove crucial. Should he fight for the bone, or defer to his rival and go off in search of another? The typical dog follows a simple decision rule: If his rival is considerably bigger than he is, he defers – if they are roughly the same size, he might fight, depending upon how hungry he is – although if his rival is smaller, he will almost certainly fight, or a least make it known that he intends to.

Thus, it is important that dogs devote scarce neurological capacity to the support of an elaborate mechanism that raises the hackles on their backs whenever they face off against rivals, and as well as this, they must also be able to reach a quick and accurate judgment about how large their rival is.

Hackle-raising makes the animal appear larger, and is therefore more likely to dissuade his rival from fighting. Even though all dogs raise their hackles, only one dog in any pair can be larger than his rival. Dogs as a group would fare better if the neurological capacity that supports hackle-raising were used instead to support better hearing or a keener sense of smell.

Baby birds in their nest must squawk themselves hoarse because their parents make the (not unreasonable) assumption that the bird who squawks loudest must be most in need of food. In the end, of course, there are only so many worms to go around, and nestlings as a group would fare better if all squawked more softly. Yet any individual chick that showed restraint would be much more likely than his siblings to starve.

Intraspecific competition in Human social dynamics

This Darwinian theme of conflict between the interests of individuals and groups also plays out amongst human affairs in countless ways, both trivial and profound. Here is a selection of examples:

Shouting at parties: Whenever large numbers of people gather for conversation in a closed space, the ambient noise level rises rapidly. After attending such events, people often complain of sore throats and hoarse voices from having had to speak so loudly in order to be heard. If all the guests spoke at normal voice levels, they would avoid these problems. And, because the overall noise level would be lower, they would all hear just as well as when they all shout at one another.

So why shout? The problem again stems from the difference between the incentives seen by individuals and those seen by the larger group. Everyone starts by speaking at normal levels, but because of the crowded conditions, it’s difficult for conversation partners to hear one another. The natural solution from the point of view of you and your conversation partner is to simply raise your voices a bit – but that is also the natural solution for all other conversation pairs – and when all raise their voices, the ambient noise level rises, so that no one hears any better than before.

This is certainly wasteful, but here again there is precious little that individuals acting alone can do about it, since if any single conversation pair were to lower their voices while others didn’t, they wouldn’t be able to hear anything. Nobody wants to go home with raw vocal cords, but we humans apparently prefer that cost to the alternative of not being able to engage in conversation.

Anabolic steroid use: The offensive linemen of the Dallas Cowboys, when they won the Super Bowl in 1996, averaged 333 pounds per man, and 300-pounders on the front lines of other teams have become the rule rather than the exception. In the 1970s, by contrast, offensive linemen in the National Football League averaged barely 280 pounds, and the all-decade linemen of the 1940s averaged only 229 pounds.³ One reason that American football players of modern times are so much heavier is that player’s salaries have increased sharply over the past few decades, which has led to much more intense competition for the positions. Size and strength are the two cardinal virtues of an offensive lineman and, other things being equal, the job will always go to the larger and stronger of two rivals. Then, because size and strength, in turn, can be enhanced by the consumption of anabolic steroids, individual players have compelling incentives to consume these drugs.

Yet, if all American football players take steroids, the rank ordering of players by size and strength – and therefore the question of who lands the plum jobs – will be largely unaffected. However, since the consumption of anabolic steroids entails risk of serious long-term health consequences (heightened aggressiveness, severe psychosis, circulatory disorders, testicular atrophy, abnormal sperm morphology, and possibly a variety of Cancers⁴) American football players as a group are clearly worse off if they consume these drugs.

Military arms races: The frantic efforts of nations to acquire more weapons than their rivals is one of the most costly instances of the conflict between individual and collective interests. From each individual nation’s point of view, the worst possible outcome is not to buy armaments while its rivals do. Yet when all nations spend more on weapons, no one is any more secure than they were before.

Most nations recognize the importance of maintaining military parity, and the result is all too often a wasteful escalation of expenditure on arms. All nations would spend much less on weapons if they could make their military spending decisions collectively. And then with the money thus saved, each side could spend more on things that promote, rather than threaten, human well-being.

Overharvesting: Disparities between individual and group incentives have also led to over-fishing of coastal waters, overgrazing of common pasturelands, and over-cutting of forests. The problem is not that individual fishermen don’t know that their activities threaten the viability of coastal fisheries; or that individual hunters don’t recognize that Rhinos are in danger of extinction; or that individual loggers don’t realise that valuable ecosystems are often destroyed by clear-cutting. In each case, individuals know all too well what the collective consequences of their actions will be. Yet when property rights in the use of valuable resources are not clearly defined and enforced, no individual is in a position to take effective action. If a Rhino isn’t killed by one hunter, he will simply be killed by another; fish not taken by one boat will be taken by another; and logs left standing by one company will be quickly claimed by another. In its various forms, the over-harvesting problem has been called “The tragedy of the commons”⁵.

High-heels and Cosmetic surgery: In species in which males invest little in the care of offspring (probably the majority of mammals) males typically battle one another for access to females. But in a small number of species – including Human beings and a handful of other species in which males invest more heavily in the care of offspring – the pattern is somewhat different. In these species, competition amongst males is still common, but we also see competition among females for males. And here again, the Darwinian logic is simple: Whereas females in most species can expect males to contribute no more than their genes and can therefore afford to sit back and let males slug it out, Human females stand to gain a great deal if they can monopolize the services of a relatively able caregiver – and thus, women have an incentive to compete.

Competition amongst Human females plays out in various different ways in different cultures, but invariably at least some aspects of it are wasteful. So, for example, in cultures in which height is viewed as attractive, it’s common for women to wear high-heeled shoes. In cultures in which large eyes are valued, most women wear makeup that makes their eyes look larger. In cultures in which youth is considered attractive, most women use makeup to conceal signs of ageing. In cultures in which body hair is considered unattractive, women may submit to electrolysis treatments. And in cultures that place a premium on large breasts, many women undergo surgical breast augmentation.

All these steps involve costs – sometimes very high costs. Even apparently innocuous actions like wearing high heels can cause foot, ankle and back injuries, tendon shrinkage, and misalignment of internal organs. In a small but not-negligible proportion of cases, cosmetic surgery leads to serious infection, disfigurement, and even death. And yet in each case the advantages that people seek are, to a considerable extent, mutually offsetting. Thus, the height advantage that someone gains from wearing high-heeled shoes is neutralized once high heels become the norm. Yet, as with Military arms races, these costs often cannot be avoided without incurring even greater ones.

To summarise, nobody gets any genetic advantage from spending hours lifting weights, filling out Crosswords or Suduko puzzles. Therefore, it’s only worth continuing those activities if you enjoyed them as pastimes, in the first instance. You may, however, be interested to learn instead that according to the Mayo Clinic, men wanting to make sure their sperm are healthy, are recommended to take a daily multivitamin that contains Selenium, Zinc and Folic acid, since these nutrients are important for sperm function.

References:

1. Cronin, H., The Ant and the Peacock: Altruism and Sexual Selection from Darwin to Today (Cambridge University Press, 1991)
2. Hamilton, W. D., M. Zuk, ’Heritable true fitness and bright birds: a role for parasites?’, Science (1982), 218:384-87
3. Noonan, D., ‘Really Big Football Players‘, New York Times Magazine (December 14, 1997), 64ff
4. Windsor, R.E., D. Dumitru, ‘Anabolic steroid use by athletes: How serious are the health hazards?’, Postgraduate Medicine (1988), 84:37-49
5. Hardin, G., ‘The Tradegy of the Commons‘, Science (1968), 162:1243-48

Posted by Jonathan as Sociobiology, Sociology at 5:20 AM GMT

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The usefulness of sex, according to an intriguing new theory of evolutionary biology, may be its ability to promote genes that play well with many other partners, rather than just those that shine with one specific set of genes.

This idea of genetic mixability, described in the journal Proceedings of the National Academy of Sciences hits on the difficulties that Evolutionary biologists have had in understanding the role of sex in population genetics and Darwin’s survival-of-the-fittest mantra.

Lead author Adi Livnat, a Miller Institute post-doctoral fellow based at UC Berkeley’s Department of Electrical Engineering and Computer Sciences said:

During the past century, it has often been assumed that sexual reproduction should somehow facilitate the increase in fitness under natural selection, leading to the ‘best’ combinations of genes. But no agreement has been reached on whether and how this could really work. One might think, for example, that by bringing together genes from different individuals, sexual reproduction could create a very successful combination of genes. But just as sexual reproduction will create that very successful combination of genes, it could also break it down in the next generation.

That sex can actually impede the increase in the fitness of the population raises the question of how it could remain the dominant form of reproduction across all manner of species, when the fact remains that sexual reproduction (the merging of genes from different individuals to create genetically unique offspring) is the reproductive method of choice from humans to plants to many fungi. So, this form of reproduction must be doing something right in terms of evolution.

Thinking laterally, instead of making the standard assumption that sexual reproduction increases the average fitness of a population, the researchers came up with a new measure they call “mixability” to represent a gene’s ability to perform well across many different combinations.

They tested the mixability measure in a number of scenarios, within a well-established population-genetic framework and found that if the goal is to maximize fitness by finding a particularly good combination of genes, asexual reproduction – which increases a population’s numbers at a much faster rate than sexual reproduction – works very well.

In contrast, sexual reproduction, through the process of recombination and segregation of chromosomes, strongly favours genes that work well in many different variations rather than any one good combination. In that view, the authors wrote, alleles of the same gene compete with each other based upon how well they perform on average rather than how well they perform in any one specific combination.

Co-author Marcus Feldman, Professor of Biology at Stanford University, and a world-renowned theorist in evolutionary biology said:

It’s important to note that during the process of evolution, the mixability value increases, though it doesn’t increase all the time. The approach we take is different from usual because we’re interested in Evolutionary transience, and in the long run, our mixability value may actually decrease because too much variability is lost from the population.

Even so, sexual reproduction has a great advantage for mixability compared with asexual reproduction, according to the models used in the paper.

Livnat started thinking about this problem in discussions with co-author Christos Papadimitriou, Professor of computer sciences at the University of California, Berkeley, and a leading computer theorist whose research includes optimization algorithms. Such programming is widely used to find best outcomes in applications such as computer networks, transportation planning and financial models.

The researchers explained that of the two main techniques for optimization programming, the first, known as simulated annealing, solves problems using a process analogous to asexual reproduction, whilst the second, known as genetic algorithms, is inspired by sexual reproduction. Genetic algorithms should theoretically be the more efficient of the two techniques for finding the best solutions to a problem because they mimic an approach that is so dominant in nature. However, it turns out that genetic algorithms often perform no better than simulated annealing.

Professor Papadimitriou said:

We were trying to figure out why an algorithm that mimics a good idea in nature was not coming up with better results. It dawned on us that what sexual reproduction is doing is not maximizing fitness, but doing something more subtle. It is bringing about genetic variants that perform well across many possibilities in connection with a great variety of genetic partners. If a particular gene variant can do well with many other alleles, not just a highly specialized variant, evolution is advanced.

The researchers noted that when the human genome was sequenced in 2003, there was surprise that humans didn’t possess far more genes than other species. It turns out that how those genes are combined may be a critical factor in distinguishing humans from other species, supporting the importance of flexibility over fitness.

Feldman, who has studied the evolution of sex and recombination for more than three decades, said he expects this new theory to trigger much debate among his peers, adding:

This problem of understanding sex will go on being one of the central issues in evolution.

Posted by Jonathan as Biology, Sociobiology at 12:53 AM GMT

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Researchers, based at the Institute of Psychiatry, King’s College London have been analysing archived data from former US soldiers who underwent intensive testing for intelligence, detailed medical examinations and provided semen samples.

The results, published in the journal Intelligence showed that in the men who performed better on intelligence tests, total sperm count was higher, as well as sperm concentration and motility. This suggests that in our ancestors, intelligence and sperm quality were linked, so intelligent men were more likely to reproduce.

It might be argued that brighter people would be less likely to smoke, and more likely to take exercise, both of which are known to impact on mental performance. But, even when lifestyle factors such as body mass index, use of alcohol, tobacco, marijuana, and hard drugs were taken into account, there was still a statistically significant correlation between intelligence and sperm quality.

Lead researcher Dr Rosalind Arden said:

We are not trying to say that under modern conditions intelligent men are going to have more children.

We wanted to test the idea that intelligence is favoured by natural selection.

We look forward to seeing if the results can be replicated in other data sets, with other measures of intelligence and other measures of physical health that are also strongly related to evolutionary fitness.

Dr Allan Pacey, Senior Lecturer in Andrology at the University of Sheffield commented:

The fact that it’s possible to detect a statistical relationship between intelligence and semen quality in adult men probably says more about the co-development of brain and testicles when the man was in his mother’s womb, and therefore how well they both function in adult life, rather than suggesting that playing Sudoku can somehow stimulate more sperm to be produced.

Posted by Jonathan as Biology, Sociobiology at 11:07 PM GMT

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In an international index measuring one-night stands, total numbers of partners and attitudes towards sex, Britain comes out ahead of America, Australia, France, Germany, Italy and the Netherlands; making the British the most promiscuous of any large western industrial nation.

The study was conducted by asking more than 14,000 people in 48 countries to fill in an anonymous questionnaire about their attitudes towards casual sex and how many people they expected to sleep with over the next five years. The results were then turned into an index of ‘sociosexuality‘, which measured how sexually liberal people are in thought and behaviour.

Most individuals scored between 4 and 65. Finland ranked highest with an average of 51 and Taiwan came lowest with 19. Britain’s average score of 40 placed it 11th overall – behind countries such as Latvia, Croatia and Slovenia, but highest amongst major western industrial nations.

The researchers behind the study suggest that high scores might be correlated to the way society is increasingly willing to accept sexual promiscuity among women as well as men. Cultural developments have also meant women are now as able to engage in no-strings sex as much as men.

David Schmitt, a Professor of Psychology at Bradley University, Illinois, who oversaw the research, said:

Historically we have repressed women’s short-term mating and there are all sorts of double standards out there where men’s short-term mating was sort of acceptable but women’s wasn’t

Britain’s high score was attributed to factors such as the decline of religious scruples about extramarital sex, the growth of equal pay and equal rights for women and a highly sexualised popular culture.

Professor Schmitt pointed out that the ratio of men to women is one of the factors that determines a country’s ranking, noting that high scores in many Baltic and eastern European states could be linked to the fact that women outnumber men, and thus are under more pressure to conform to what men want in order to find a mate. By contrast, in Asian countries, men tend to slightly outnumber women, so it is the men who have to conform to what women want.

The findings are backed up by earlier research showing that the British are more likely than other nationalities to have “stolen” another person’s partner, and apparently a third of British men are in relationships with women that they have poached from other long-term relationships. Amongst British women, 28% had poached their boyfriend from another relationship, rather than forming a relationship with a single man.

This compares with America, where just 17% of men had “stolen” another person’s girlfriend. In France only 10% of both men and women were poachers, whilst in Germany the figures were 17% for men and 14% for women.

Interestingly, in more liberal countries such as Britain, women might even be becoming more promiscuous than men, since one of the latest theories emerging from Evolutionary Psychologists such as Professor Schmitt, is the idea that when women are at their most fertile, they become even more willing than men to consider one-night stands.

However, there are still key differences in the behaviours of men and women, especially regarding the ages at which they are most sexually liberated. Schmitt found that men tended to have the most sexual partners, and to try hardest to acquire new ones whilst in their twenties. On the other hand, Women’s promiscuity and lustful thoughts tended to peak whilst in their thirties.

Posted by Jonathan as Psychology, Sociobiology at 3:26 PM GMT

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