It's a well-known joke that men care about the size of a woman's chest and women care about the size of a man's wallet. You've undoubtedly seen some hideous yet stupidly rich man in his nineties walking around with a 20-something super-model and thought "I know what she's after". Similarly, you've probably seen guys lining up around the block for a vapid woman with no personality who just happens to be good-looking. "Men are shallow" we scoff, feeling smug and holy about ourselves. It seems we judge men for going after beauty and women for going after financial wealth, but is this fair?
I recently saw a series of cynical YouTube videos in which a woman is approached by a man and asked on a date (harassed, really). She turns him down but then the twist comes...he is revealed to be extremely wealthy e.g. he gets into a sports car, pulls a ton of notes from his pocket, or reveals himself to be the author of a popular Science book available now from Amazon. Suddenly the woman reverses her stance and asks if the guy still wants to go on a date. The man responds by laughing in her face and accusing her of being a "gold-digger". Classy stuff.
I can't help but feel it would be easy to do a gender-reversed version. Some guy is approached by a traditionally homely woman and propositioned for a date, which he turns down. Then the hilarious gag is revealed "oh that's a shame, because I'm asking for my friend..." cue woman suddenly appearing from behind a tree who is stupendously pretty and the man reverses his mind. Television networks, I await your call.
I suppose we could all try not judging other people for their relationship choices and accept that human beings are emotionally complicated, but where's the fun in that? Everyone loves a gossip, so today I thought I'd look at the question of dating stereotypes and ask whether it's biologically accurate. What do we look for in a partner and do these couples last?
Oh, I should point out that although this is always a family-friendly blog, I will be referencing the fact that humans (spoiler alert) have sex for the purposes of reproduction and fun. I'm sorry we're like that as a species. I'll see if I can do something about it!
The Game is On
Biologically speaking, the point of finding a sexual partner is to pass on genes. Males do this by producing millions of sperm cells every day, making them expendable and easily replaceable. Females however are born with a few dozen eggs which never get replaced, making them valuable.
Females also endure a long and uncomfortable pregnancy, removing them from the mating-arena for several months. This is followed by the pain of childbirth and in some species a lifelong commitment to child-rearing. Biologically, a female has to be careful when selecting a mate because it represents a greater investment. If you breed with a weak, unhealthy male the offspring are less likely to survive and you’ve just wasted a precious egg.
Males, on the other hand, can produce genetic material on demand so they don’t need to exercise as much caution. For them, the optimum strategy is to breed with as many females as possible. Because both sexes are trying to do different things, a balance has to be found and most species tend to adopt one of two strategies. Either they enter into pair-bonding arrangements, or they enter into a tournament.
In pair-bonding species like gibbons or owl monkeys, males and females find a mate and remain with them for many years. The advantage for the female is that the male will help with child-rearing, the advantage for the male is that he is guaranteed a mate and doesn’t have to use energy searching for new females.
In this kind of species, males and females are sizing each-other up in order to choose who to have sex with. Both want to make a careful selection and impress partners simultaneously, so everyone is trying to make themselves look good but also scope what’s on offer.
In a tournament species like chimpanzees or gorillas, the females are in charge of breeding and males have to compete for attention. Once a female has chosen a mate, a brief sexual union takes place and then the male often leaves, trying to impress someone new. The advantage for males is that they breed with more females, while the advantage for females is that they control which males are worth their time and only select the very best of what's on offer.
In tournament species the males tend to appear very different from the females since they are the ones having to look impressive (think of the difference between a peacock and a peahen). Males also tend to have a large testicle-to-body ratio in order to produce lots of sperm cells. We call this disparity between the sexes 'sexual dimorphism'. In pair-bonding species however, the two sexes look similar because neither is in charge of selection. The testicle-to-body ratio is also smaller because males don’t need to go to the trouble of having large ones (a potential risk of injury).
The human species, as you might have guessed, sits awkwardly in the middle. Human testicle-to-body ratio is halfway between tournament and pair-bonding species. There are also some sexual differences between men and women but not too many e.g. women have breasts and wider hips while men have muscle mass and broader shoulders, but if you’d never seen humans before you might find it difficult to tell them apart.
Humans are a species where males try to breed with many females but also search carefully for a worthy female to settle with. The reverse is also true; females will be on the lookout for an advantageous male but are also trying to advertise themselves for selection. The outcome is that men and women are both trying to impress each other with a slight tendency toward men wanting multiple partners and women being picky.
Incidentally, this means the belief that men are more sexually promiscuous on average is completely false. In fact, it’s mathematically impossible. Because the number of men and women are equal, the number of pairings which occur on average has to be equal too. If we had five men and five women and one man mated with each woman, the female average is one partner each. But since there were five men and five encounters, this is an average of one partner per man. If each woman had sex with all five men however, the men’s average would increase to five but so would the women’s!
Logically, men and women have the same number of sexual partners on average. Where the myth arises is that men apparently try to have more partners than women, but because women are more selective everything balances out.
Do I look good in this?
Now we can ask the real question: what do males and females in a species look for in a potential mate? Typically, there are five characteristics which drive the process:
1. Symmetry – Having a symmetrical shape tends to be the result of a good immune system (nobody knows why). If you are symmetrical you are healthy and therefore will have healthy babies. In fact, the Biologist Craig Roberts found that women’s faces literally change shape around ovulation to become more symmetrical, increasing attractiveness. Men, on the other hand, don’t go through a monthly cycle of sexual change so their shape remains fixed.
2. Sexual exaggeration – We look for members of the opposite sex who are extreme versions of what typifies that sex. The reason, known as the Zahavi handicap principle, is also to do with health. Your immune system takes a lot of energy to maintain. In fact, it’s the third biggest energy demand after muscle movement and brain activity. If you have a really strong immune system you therefore have lots of energy spare and a good way to advertise that is by showing off, wasting energy on secondary sexual characteristics. Look at my ridiculous antlers, check out the size of my tail feathers, see how big my throat-pouch is! My immune system’s so good I’ve got energy to spare on growing these.
3. Fertility characteristics – This one is obvious. If you’re not fertile then mating with you is a waste of time, so you have to look as fertile as possible and advertise it constantly. Having lots of testosterone as a man gives you things like a deep voice, body hair, muscle mass etc. as well as higher sperm-cell production. Subsequently looking more masculine is an advertisement that you are a good baby-maker. Likewise for women, chemicals like estrone and estradiol are responsible for feminine characteristics as well as fertility so the more feminine you look the more likely you are to be good at baby-making.
4. Homogony – You tend to seek out breeding partners who are physically similar to you (but not too similar). If you’re a chimpanzee your brain wants you to mate with other chimpanzees. It’s far less likely for a successful breeding to occur if you have sex with a gorilla (chimpanzee-gorilla crossbreeding is theoretically possible, but has never been achieved). Your brain encourages you to breed with similarity so you go after people who remind you of yourself a little. The flip-side is that breeding with someone too genetically similar is not favourable because it increases the chances of genetic diseases being inherited. That’s why we usually avoid mating with close relatives. But it may explain why some species show a slight bias for sex with cousins (looking in your direction Einstein).
5. Child-rearing – If you’re going to be passing your genes into a smaller unit, you need reassurance it’s going to survive and if the potential mate is a capable parent, they are obviously going to be a suitable partner. The first four characteristics are to do with appearance and are driven by finding good genes to produce a healthy baby. The fifth is about parenting of that baby and this is the crucial difference between the sexes.
Parenting is the most important factor because it has a bigger impact on whether the baby actually survives. If the child is born healthy but the parent doesn’t protect or feed them, they’re going to die no matter how good their genes are. However if the child is born unhealthy but the parenting is good, they still have a chance of living. If you’ve got to choose one over the other parenting skills dominates good genes.
This means if you’re picky with mate-selection and you’re only planning on doing it a few times, you’ll have to stick with top priority - child-rearing. Quality of genes (physical attraction) is a luxury. If you’re not picky however you can look for good genetics as well as child-rearing skills. Not only that but if you’re attempting to have sex with many partners you don’t have to worry about child-rearing so much. Chances are one of those mates will be a good parent so physical attraction (good genes) becomes your only motivation.
You can see where this is going. If you’re the female of a species you’re more likely to take your time finding out about a male. If they are a high-ranking male in your troop, good at hunting, good at defending against predators etc. they’re more likely to provide for children.
If you’re male, you’re trying to partner up as often as possible so you don’t spend time sussing out female behaviour and personality. You’re more likely to make quick judgements about the quality of genes on offer which means emphasis on physical attraction.
We don’t deliberately do any of this of course. Men aren’t consciously deciding which women are attractive and women don’t deliberately give more consideration to a man’s status, it’s just what we’re drawn to. Men will still consider the personality of a female and women will still consider the physical appearance of a male, but it isn’t the bottom line. Women want a provider for the kids, men want good genes for those kids. Eggs are valuable, sperm are not. Women make something precious, men make something common.
It might therefore be unhelpful, even naive, to criticise people for picking the partners they do. Attacking women for choosing stability or attacking men for caring about looks is to criticise people for something they aren’t in control of. Not only that, this arrangement might actually be the optimum strategy for our species. We’re in a difficult position, halfway between pair-bond and tournament, with both genders wanting different things. There is no way to make everyone happy so a compromise must be reached.
What does the research say?
Psychology research is always a minefield. There are so many variables in human behaviour and social interactions that refuting a hypothesis is difficult. Psychology is an invaluable branch of Science but its data is often more open to interpretation than physics, chemistry or biology. Nobody ever debates that F = ma or that Helium has two electrons, but psychological studies are more broad. This is a good thing in my view however, because the human mind is complex and context is everything. We need to keep our understanding loosey-goosey otherwise we end up sticking to ideas that are precarious.
One of the most famous studies carried out on human pairing was the 1978/1982 Clark & Hatfield study. The experimental setup was simple. At Florida State University, strangers were approached by members of the opposite sex and propostioned for a date or for sex.
The words used by each propositioning party were: "I've noticed you around, I find you very attractive, would you go to bed with me/go on a date with me?" A few years later these words from the research paper were remixed into the jazz-punk song Would You by Touch and Go, making it the only pop song to get its lyrics from a scientific journal. I'm trying to persuade the other three members of my rock band to do a similar song with lyrics taken from this paper on quantum cosmology. Fingers crossed.
Clark and Hatfield found that both sexes were equally willing to go on a date (about 50% of both groups) but when it came to sex, the picture looked very different. About 75% of the men immediately said yes to sex, while 0% of the women were up for it. This would appear to confirm the breeding-selection hypothesis.
Obviously we've made the assumption that the people being approached were heterosexual. That's unlikely to have been true but statistically, heterosexual behaviour is more common among humans, so the results shouldn't be skewed too much. It looks like that's fairly cut and dried then: men are more willing to mate with a female after meeting them. But what of the status preferences of women?
One of the most shocking (to me, as a man) studies I ever came across is unfortunately one I can no longer find. I remember Professor Robert Winston making reference to it in a documentary but I cannot find the original paper...anyone out there able to help? The study carried out a simple experiment. A group of women were positioned outside a restaurant and told to rank men for attractiveness as they pulled up in their cars.
The twist was that on multiple occasions the same man walked past but with a different social status. On the first attempt he drove up in a shabby, bruised car and got out in scruffy clothes and was ranked as a bad choice. The same man, a few hours later, drove up in a swish sports car, an affluent suit and was ranked as an ideal choice by the women. It's the exact same guy, yet different status made him literally unrecognisable.
As a man I found this result shocking, but that's because men tend to focus more on looks, and it's unlikely I would mis-recognise the same woman in different clothes. Women I've spoken to about this study aren't shocked however. A man's status really does change his attraction factor.
So does that settle it? Well...not so fast. In 2015 Andreas Baranowski and Heiko Hecht updated the Clark/Hatfield study. Initially they replicated the results on a modern campus and nightclub, finding it to be the same today as back then. But in the second phase of the experiment they decided to do it in private. Women and men were invited into a "dating agency" and asked to select partners for dating or sex, being reassured that the people's profiles had been vetted by the agency. Each subject was shown ten pictures and asked to select who they would have sex with.
Men on average selected just over three. Women on average selected just under. There is a slight difference to be sure, which perhaps confirms the hypothesis, but both men and women had closer behavioural patterns than Clark/Hatfield suggested. It would appear that when men and women are asked about sex and it's done in private, with reassurance of safety, they're about even.
Perhaps one of the reasons women turn men down regularly is related to the fact that 45% of women have experienced some sort of sexual violence, coercion or intimidation from a man during their adult lives. Maybe it's also because society condemns women for having sex, so accepting a proposal in public is a shameful thing?
I've sometimes heard men justify their sexual confidence (harassing of women) by saying it's biology and everyone should accept it. But this may not be true. It looks like women and men are just as interested in sex, but the reason the discord arises is because women are treated worse than men, both by society and by men themselves. More women are raped than men. More women are shamed by their families/friends/colleagues/religious groups for having sex and so on. It's possible the stereotype of women refusing sex is actually men's doing so they should stop complaining about women being so cautious?
Maybe, just maybe, men need to stop harassing women or sexually intimidating them and defending their behaviour by saying "it's guys being guys." Maybe if men treated women better on average, women wouldn't feel sexually intimidated and everyone would actually have more sex and society would be happier as a whole? Just a thought.
What about love?
What these studies look at is sexual attraction and the desire for breeding. But where does emotional connection come in? This is where things get not only optimistic, but surprisingly touching.
A 2014 study conducted by Elizabeth McClintock reviewed 1,507 couples and assessed where they were in terms of attraction to one another, relationship stability and how long the relationship lasted. What she found, overwhelmingly, was that pairings based solely on attraction (physical or status) did not last. What a shock.
The model of men going for beautiful and women going for rich is definitely there and it can lead to a lot of relationships starting...but not surviving. McClintock found that relationships which actually work best (happiest couples) and survived the longest were when people go for what she calls matching. Simply put, nice guys pair with nice women. Hot women pair with hot men. Wealthy men pair with wealthy women and so on.
A relationship where a rich man propositions an attractive woman and the two "hit it off" is definitely a common occurrence, because the woman gets security for raising kids and the man gets a beautiful partner, but such relationships are, statistically, unlikely to last or be happy. It's a short term strategy only.
People should instead look for matches in personality...which sort of confirms another long-held truism. Relationships built on attraction or convenience rarely work. Personal connection wins out. How about that? Science actually confirms that loving relationships work better.
Is Evolution Really That Sentimental?
Arguably the world's leading expert on the evolutionary development of love, attraction and human relationships is David Buss of Austin University (much of whose ideas I used in this blog). Buss has spent over thirty years studying differences between sexes and in one of his most famous studies (1986 with Michael Barnes) Buss asked hundreds of men and women to decide what features of a partner were most important to them.
Buss and Barnes found there was certainly a tendency for men to go for physical appearance and for women to seek wealth. Men were slightly drawn to younger women and women to older men, but what they found was that the number-one thing both sexes looked for is simple...someone who treats you nicely. Not someone who provides for you or someone who looks good for you - someone who is nice to you.
Short-term attraction strategies are all about sizing someone up and that's when physical attraction or social status come into play. But long-term success is about something so obvious it seems ridiculous we needed Scientists to research it. But there you have it. You might be a super wealthy man who owns a flashy sports car and a business; that will probably help you get women for short term sex. And you might be a gorgeous woman with a voluptuous figure and flowing hair that will draw men's attention. But if you want to build a relationship with someone you have to do something else. Be kind to each other.
But why did we develop this desire for connection over attraction? As far as we can tell, while many animals exhibit sexual desire or social loyalty, deep feelings of love seem to be unique to humans. Does it have an evolutionary advantage or is it simply an accident? Poets, musicians, painters, authors, film-makers, scientists and philosophers have been grappling with that question for a long time and I don't think I can offer an answer. Love does seem like an anomaly.
After all, there is an alternative route which guarantees equal reproduction for all. It’s the one chosen by bacteria...bypass sex altogether. Bacteria reproduce autonomously, so they have no need to develop competition strategies which makes them more efficient breeders. However, because there is no need to find a partner, there is also no need to develop the emotions which encourage it to happen. Bacteria don’t feel companionship, they don’t feel love and they don’t feel empathy. Personally, I think those features are worth hanging onto, accidental or otherwise.
Love may indeed be a Darwinian screw-up. But even if it is, it's one of the most important driving forces in our emotional lives. Feelings of love, be they romantic, family-oriented or whatever, are the reason we're good to one another. I might even go so far as to say that's why kindness is more important in a relationship than anything else. A person who is attracted to you wants you as a possession - a person who feels compassion for you is going to treat you well and that is what makes you want to stay with them.
I say on my home page and at the end of my book "Science will save our species". It's become one of my catchphrases and I stand by it as a mantra. But I think something else might be even more important. Science is the tool we need to save our species, but a desire to be kind to each other tells us how to use that tool. I think it's possible that kindness and love, more than Science, are the things which will save us from extinction. They are perhaps the reason we will save not just ourselves, but each other as well.
I love science, let me tell you why.