Archive for the ‘Science’ Category

Do ghosts exist?

Posted on February 14th, 2011 in Science, Skepticism | 8 Comments »

I’ve been playing around with Quora recently, which is a new social website revolving around questions and answers. Since some of the questions posed are contentious, it’s possible to get into some quite fun debates on there, although the system of voting and thanking generally means that sane, well-reasoned and well-evidenced answers rise to the top.

In a recent exchange, I ended up posting a very long comment which the Quora software mangled somewhat when I pasted it from Word. I’ve therefore reproduced it here, with a few snippets of the earlier conversation for context. You can see the whole saga, complete with any future additions, here.

Zoletta Cherrystone
I have had more than one ‘ghost’ experience, and completely believe in the spiritual world. I believe this without doubt, because of what I’ve witnessed with my own eyes.

Tom Salinsky
I’ve seen plenty of things with my own eyes which were later proved not to be the case. You’ve never seen an optical illusion before? First-hand testimony is a very poor way to establish objective truths about the world.

Well, Tom, I don’t think there’s a test to prove that pretty much all of us can ‘feel’ when a person is standing behind us, but we all know we can.

I said, earlier, that I’ve had more than one ‘ghost’ experience. It was a huge understatement. I’ve had dozens, from early childhood until the present. Things that simply have no other explanation, and some of which are too connected with a dead relative to dismiss.

An optical illusion is not going to explain away a light switch snapping (I say snapping because this was a very old one, and hard to maneuver) into the off position. Or a book physically being placed in a peculiar way in a room other then where you left it just as you fell asleep with no one else in the house with you. Or hearing your name being spoken aloud in a new house when you’re in it entirely alone, accompanied by other instances of objects being slammed down at key moments (no vibrations, no way for these items to casually fall on their own) and then to make phone calls and find out that the previous owner experienced all the same.

“Am I a man dreaming I’m a butterfly, or am I a butterfly dreaming I’m a man?”

With all the paranormal investigators out there recording voices, snapping photos, and catching things on tape, that’s about as much ‘proof’ that anybody is ever going to get, yet still it is dismissed.

So my question to you now becomes this: What is required to ‘prove’ this phenomena?

This is going to be far too long, but here goes…

ZC: Well, Tom, I don’t think there’s a test to prove that pretty much all of us can ‘feel’ when a person is standing behind us, but we all know we can.

TS: This shows a distinct lack of imagination. Can you really not conceive of a way to test this hypothesis? Here’s one. Blindfold a series of subjects and deafen them by playing white noise in their ears (since this is not a test of one’s ability to see or hear people). According to a predetermined, but random sequence, have people either stand behind them or not, and have the subject indicate when they feel a presence. If they are right much more often than chance would suggest then there is a real ability here. BUT UNTIL A TEST LIKE THIS IS DONE, we can’t say for sure that such a phenomenon exists. Personal testimony is not enough. Confirmation bias will ensure that we remember only those occasions when we ‘feel’ someone behind us and are correct. (I do not give an opinion as to whether this ability is real or not.)

ZC: An optical illusion is not going to explain away a light switch snapping (I say snapping because this was a very old one, and hard to maneuver) into the off position… etc

TS: All of these are artifacts – events in the past for which the only evidence is your testimony, which may or may not be distorted by time, the limitations of your senses and your desire to believe in the existence of spirits. But you don’t get to jump from “I have no explanation for the movement of this light switch / book / strange noise / falling objects, and BECAUSE I HAVE NO EXPLANATION IT THEREFORE MUST BE A GHOST.” You are just substituting one unknown for another. I submit that all of these phenomena, even if they could be definitely established as real (which at the present time, they cannot) could be equally well “explained” by aliens, Jesus, elves, fairies or any other fantasies you choose to invent. Finding out objective truths about the world is not done by identifying apparently anomalous events and then announcing that your predetermined idea is “the only explanation”.

ZC: With all the paranormal investigators out there recording voices, snapping photos, and catching things on tape, that’s about as much ‘proof’ that anybody is ever going to get, yet still it is dismissed.

TS: But not dismissed without reason. Dismissed because the supposed evidence is so weak. “Ghost” photos are routinely analysed and shown to have mundane explanations, but even when no mundane explanation presents itself, my argument above still applies. What you call “ghost”, I call “alien”, and someone else calls “Jesus” and so on, depending on taste, upbringing, bias and so on – depending in no way on the phenomenon itself.

Recording voices is a particularly clear example. So-called EVP (electronic voice phenomena) are generally agreed to be artifacts of recording devices with automatic gain control, coupled with the human brain’s automatic pattern-detecting habits. The former is a matter of electronics. If you have a device which records more when the environment is quiet, it will record more NOISE. Then, a person hoping to hear particular words or phrases will manage to pick them out of that noise. You rubbish my showing how your subjective experiences may be unreliable with reference to optical illusions, but this is an auditory illusion. The phenomenon is known as pareidolia – people finding patterns in randomness – and it explains why people believe they see Jesus in a piece of burnt toast, faces on the surface of the moon and hear voices in static.

Here’s a great example of how easy it is to hear words that aren’t really there – once you know what it is you are supposed to be hearing.

Skeptic and magician Derren Brown was confronted with a devotee of EVP who swore that when he asked questions of spirits, they obediently provided meaningful answers which were recorded during silences on his Dictaphone. When Derren went recording with him and was given the opportunity to ask a question himself, he said “If there really is a spirit there, confirm your presence by remaining silent once I’ve finished speaking.” On playing back the tape, the usual roar of static was heard – exactly as one would expect if the phenomenon was entirely due to automatic gain (and subsequent pareidolia). Exactly the opposite behaviour of the previously always-obliging phantoms.

ZC: So my question to you now becomes this: What is required to ‘prove’ this phenomena?

TS: Just the same as to prove any phenomena. At a minimum: the result must be repeatable (which your accounts of magic light switches and falling objects are not, unless you propose to take me to a haunted house – a proposition I would relish); and it must have a low probability of happening by chance (which is not true of EVP). I have yet to see a piece of evidence for ghosts which would even meet these two criteria, but notice that these are necessary but not sufficient to establish that a particular phenomenon or effect is real. And even if the reality of an effect is established, this doe not in turn immediately allow us to conclude that the cause is a departed spirit. Once again, you only get to jump straight from “unexplained” to “ghosts” by CHOOSING ghosts, not by making a genuine discovery about the world.

The magician and escapologist Harry Houdini devoted many of his later years to exposing the mechanisms used by fraudulent psychics, but nevertheless he hoped against hope that the stories they told were true and that he could be reunited with his beloved mother. Before he died, he arranged with his wife that she should hold a séance every Halloween after his death. He also gave her a secret phrase known only to the two of them. Houdini’s codeword reproduced by a psychic after his passing would have been marvellously strong evidence for the existence of life after death. Sadly, after ten attempts and no appearances by Houdini’s spirit, his wife abandoned the task.

Of course, the real reason that most people don’t believe in ghosts is not because the evidence is so flimsy (although it is). It’s because there is no plausible mechanism which could possibly exist to preserve the personality after death. Every single experiment ever done on the subject shows us that the personality and memories are generated by the brain. After death, that pattern of neurons is destroyed and no possible way exists for that pattern to be preserved, with no power being fed in to the system and with no physical substrate on which the pattern could be recorded.

But I don’t even ask for scientific plausibility. Let’s start with one repeatable, low-probability event, the experiment designed in such a way as to rule out conscious or unconscious fraud. If we discover a genuine phenomenon, then we can start theorising about possible causes.

See, I said this would be too long.

The difference between science and magic

Posted on November 21st, 2010 in Culture, Science, Skepticism, storytelling | 1 Comment »

Clarke’s Third Law: Any sufficiently advanced technology is indistinguishable from magic.
- Arthur C Clarke

Harry Potter bursts back on to our screens again this week, with the final book split into two no-doubt lumberingly ponderous full-length motion picture “events”. But, we must take solace in the fact that a) it will soon all be over and b) remember that magic has been a huge part of the fabric of narrative since stories began and try not to be too grumpy about the success of this “franchise”. If the appeal of stories is their ability to take us to places and show us things which ordinary life denies us, then it’s easy to see why magic should play such a strong part in especially early stories. Most fairy stories have a magical element – in fact the word “fairy” implies magic.

As we grow up, we leave such things behind, for the most part. The broad appeal of those Harry Potter books and films (and the amusing existence of editions of Harry Potter novels with “adult” covers and a £2.00 price premium) is a notable exception, but especially among male readers, although fairy stories are left behind, fantasy and especially science fiction stories remain popular.

I have observed before that the key feature of stories, the primary quality which distinguishes story from not-a-story is cause and effect. Without cause-and-effect, all you have is a succession of images. (Ironically, if you present such a succession of images to an audience, they are apt to invent the missing cause-and-effect, justifying the action they see in terms of A causing B, such is the storytelling hard-wiring in the human brain.)

Even in stories which don’t present themselves as fantastical, we can often see cause-and-effect being applied in a very limited way. Consider the phenomenon, often noted in pulp, pop or escapist fare, of “goodat”. If characters suddenly announce some convenient talent, skill, expertise, relationship or ability hitherto unmentioned and unsuspected, the audience is likely to feel cheated. “Oh, didn’t I mention I can speak Japanese / crack safes / recite pi to 150 decimal places / fly unaided / control birds with the power of my mind?” It doesn’t matter if these powers are magical, merely require talent and/or practice or are borderline. Conversely, however, if it is set-up that the character in question is “goodat” languages / escapology / mathematics / psychokinesis / animal sympathy, then the audience will probably accept almost any manifestation of this ability, no matter how fantastic. The archetypal version of this would be – as I think Eddie Izzard noted – the ability of someone who is goodat computers to hack into any system in a matter of minutes, just by waggling their fingers lightly over the keyboard and announcing “I’m in”.

So far, so fair enough. Storytellers take short cuts but even bad ones stop short of outright cheating. But there’s a difference between someone, for example, using their total mastery of Spanish to eventually make communication possible with a person who speaks only Catalan – and on the other hand, somebody uploading a Macintosh virus to an alien computer. I suggest that the latter is magic and that the distinction lies in the cause and effect.

Let’s pause for a moment and consider three ways in which a fictional person may be made to disappear before our eyes – Star Trek transporters, Star Trek phasers and Harry Potter vanishings. In Star Trek as you may know, a device known as a transporter is able to whisk people from one location to another. In effect, this device disintegrates the body at one end, transmits only the pattern (transmitting data is much quicker and easier than moving mass I suppose) to the other end, where it is reassembled. The practical difficulties of achieving this are not to be underestimated. A human being is composed of around 10^25 atoms, the exact location and type and state of which all have to be recorded. That’s a heckuva big file. This data is then transmitted to a precise location where no specialised machinery exists, and then the original body is reconstructed out of – what exactly? The TV shows, films and books are generally vague on this point.

But you could (and I’ve no doubt others have) construct vaguely plausible theories about what is going on here. The transporter pad creates a sort of cone or column around the person to be “transported” and everything within that column is processed. 23rd century computers have to “lock on” to remote locations. Maybe something like a tractor beam (not that that exists yet either) is used to process atmospheric atoms within a similar column at the destination in order to make the mass required to reconstruct the transportee. It’s a hugely big problem, but as presented in Star Trek, a hugely big solution is required to make it all work – and sometimes it doesn’t. It can go wrong, with horrible consequences. So this is borderline, but I would say, provided one makes allowances for three hundred-odd years of technological advancement, there is cause-and-effect here, and crucially, the cause (although we can’t examine it all in detail) seems sufficient for the effect.

Now compare those instances with death-by-phaser. Here’s a YouTube video. Watch the phaser deaths that occur around the 1’05″ mark.

A phaser beam hits someone and they simply disappear. On a very basic level, there’s cause-and-effect here. Pull trigger on phaser, phaser beam hits redshirt, redshirt disappears. But what do we suppose the phaser beam is doing? It’s not just a narrow pencil-thin column of heat, it doesn’t drill a neat hole through its unfortunate victim. It’s not affecting the air between the barrel and the target, so it’s not radiating out a destructive cone – that would also affect surrounding matter, or if you were too close, not get the whole target. No, the phaser, or the beam itself, just “knows” what is target and what isn’t, what is to disappear in a flash and what is to be left unaffected. Not only is there no plausible mechanism by which this information could be imparted, the presentation doesn’t even begin to hint at a possible solution. Transporters are almost certainly impossible, but at least the series waves its metaphorical hands in the direction of a proper cause. Here the given cause is far to slight for the actual effect.

So, to me, death-by-phaser is far more like a wand being waved and a word being spoken and a Harry Potter character vanishing into thin air. No mechanism exists to define the scope of this action. No care must be taken to isolate only that which you wish to vanish. The waving of a wand and the saying of a word are in no way sufficient to account for the immensity and the complexity of the action which results – which is why Harry Potter is magic and not science-fiction. But magic gets smuggled in under our noses all the time. “I’m in” is a form of magic, as is the bus jump in Speed as is Radar’s ability to anticipate Colonel Blake and so on. The rule is – if the cause is sufficient for the effect, then what you have is science, but if the cause is insufficient for the effect, then what you have is magic.

But this applies to the real world of knowledge, science and medicine as much as it does to storytelling. Remember that humans look for cause-and-effect even where none is present. So, in earlier times, we ascribed the sudden and unpredictable shaking of the earth to the wrath of peevish gods. But since we have no idea where these gods are, what we have done to annoy them, or how they physically interact with the earth to cause such violence, this is magical thinking. Modern plate tectonics provides a much more thorough model (although not yet quite complete) with all the cause-and-effect you could wish for.

Another area where this test can be applied – one familiar to regular readers – is that of homeopathy. Both homeopathic and pharmaceutical treatments for a given condition, joint pain say, have the same superficial cause-and-effect appeal. You take pill. Pill makes pain better. But ask the chemist how their pill works and the answer will include fantastic quantities of detail, each element enhancing the cause-and-effect in the account. Non-steroidal anti-inflammatories inhibit cyclooxygenases, leading to a decrease in prostaglandin production. Opioids bind to and activate opioid receptors in the body’s tissues, and so on and so on. As with plate tectonics, the account may not yet be complete, but gaps are acknowledged, and effort continues to plug them. Pharmacology is science.

With your homeopathic pill on the other hand, the explanation is far sketchier. Like cures like, you may be told. How? It just does. Dilution increase potency. How? It just does. Does that mean half a pill will be twice as powerful as a whole pill? No, you have to dilute and the succuss (shake). What does that do? We don’t know. A cursory examination of the cause-and-effect supposedly driving homeopathy is enough to tell anyone that a woefully insufficient cause exists for the claimed results. Thus, we can confidently state that homeopathy is magic.

And, of course, the other thing we know about magic is that it isn’t real.

All human sexuality explained

Posted on November 2nd, 2010 in Culture, Science, Skepticism | No Comments »

As many readers will know, Stephen Fry got himself into trouble recently when an interview was published in which he is quoted as making various observations about the natures of male and female, gay and straight sexuality. The interview is not currently available online, but if you wish to read extracts from it, then try The Guardian’s coverage for less than total hysteria.

The outcry over this has driven Fry off Twitter (again) and everyone is now weighing in with their own opinion. As ever, this debate boils down to the following trite observation – men and women, taken as groups, differ in some respects but not in others. Thus, those looking for a fight can make lengthy lists of the differences and rubbish those who emphasise the similarities, or can play down the differences and give endless examples of similarities instead.

But I don’t believe Fry’s personal musings should be cause for alarm or criticism. They were offered in no way as the last word on the subject, despite his possibly rather conclusive tone, and notwithstanding his subsequent claims to have been misquoted. And they seem on their face to be perfectly fair enough. It is a readily observable fact that gay men find anonymous sexual encounters easy to come by with no need to for money to change hands. That, further, while the world is crawling with prostitutes and rent-boys, the number of straight male escorts is vanishingly small (although there’s no shortage of straight men who would volunteer to earn a living in this way). That Playgirl magazine, launched at the height of the women’s lib movement and marketed to straight women is in fact read largely by gay men. Why should not a gay man venture some speculations as to the nature and cause of these obvious differences? Especially one whose non-professional opinion is eagerly sought on a very wide range of other topics – literary, musical, technological, cultural, sartorial, zoological – almost no subject is out-of-bounds where Stephen Fry is concerned, except for female sexuality apparently.

But it doesn’t take the brain of Stephen Fry to detect the obvious difference between the sexes which emerges after even the most cursory examination of the evidence, and which no list of thoughtful similarities will do anything to dispel. Men and women certainly do tend to process the world of sex and sexuality differently. In this post, I will attempt to give an explanation of why this is so, drawn from several different pieces of research, documentaries, pop science books and lectures I have consumed over the years. Regrettably, I find myself unable to footnote any of this very extensively, but if anyone really wants to take me on, then let’s head to the comments and/or the library. Most of this is logic, observation and common sense anyway. Let’s start from first principles.

Preparatory notion 1. Men and women are different and similar and diverse

For much of the rest of this blog post, I am going to be talking about men and women as groups, types or Platonic Ideals. But it’s perhaps necessary to acknowledge that a human man and a human woman will no doubt have far more in common than a human (of either sex) and a chimp. Or indeed, a dolphin, a racoon, a banana or a bicycle. It’s not that these similarities between humans don’t exist, they simply aren’t my topic for today.

And both groups are also terribly diverse. It’s certainly possible to identify women whose behaviour sounds much more like the prototypical male I am describing, or vice-versa. I’m not suggesting that each group is entirely homogenous, and that any particular man or woman you happen to meet (or be) is guaranteed to perfectly exemplify whatever behaviour I am claiming for that group. I am claiming, however, that certain behaviours are much more typically found in men than women, or the other way round, and I don’t want the presence of outliers to distract us from the interesting conclusions we can draw about the great majority, somewhere in the middle of the bell-curve. Once again, it’s not that these outliers don’t exist or aren’t interesting – it’s just that they aren’t whom I wish to write about today.

Preparatory notion 2. The mind evolved

The field of evolutionary psychology is excitingly controversial, although those who oppose the very idea of it, often seem to be to be attacking a straw man (as in this debate between Stevens Pinker and Rose). No serious researcher is taking the field to the absurd excesses described by those who seek to denigrate this approach, and like any scientist, evolutionary psychologists are free to speculate, while being careful to separate such speculation from evidenced conclusions.

But the basic idea that the mind evolved can hardly be denied. Tiny kittens play-fight to discover how to defend themselves and catch prey, but this play-fighting is instinctive, not taught to them. Birds hatch with all the required muscle co-ordination for flight and don’t require the blank slate of their brains to be written on by an extensive programme of schooling. Human infants learn to talk even when exposed to primitive and incomplete versions of what will become their native language, as in the deaf children of hearing parents who effortlessly turn the clumsy signs of the adults closest to them into the full linguistic richness of British Sign Language (or whichever).

Although humans are blessed with an extra capacity for general reasoning and abstract thought, compared to other animals, nevertheless much of what we do remains instinctive, unconscious and shaped by billions of years of evolution, rather than a few thousand years of culture. Thus we crave foods rich in salt, fat and sugar because moderate quantities of these things are essential to our survival, and they were not always easy to come by in the African savannah. If we failed to prioritise acquiring them, or passed up opportunities to consume them, we tended to be outcompeted by those that did. These being instinctive actions, shaped and promoted (though not actually controlled moment-to-moment) by our genetic makeup, a proclivity for aggressive consumption of salt, fat and sugar became the norm in the population.

Today, when foods high in salt, fat and sugar are readily available (at least in some parts of the world), this adaptation is no longer such a benefit, but evolution shapes us only slowly. We’ve needed salt to survive for hundreds of millions of years, but McDonalds has been in business for only a few decades.

Humans evolved around a million years ago. Hominids around 15 million years ago. Primates around 75 million years ago. Mammals about 250 million years ago. Tetrapods around 400 million years ago. Vertebrates 500 million years ago.

Sex evolved about a billion years ago.

So we’ve been boy and girl for almost as long as we’ve been anything at all. It’s not inconceivable that evolution might have shaped male and female brains differently, given a billion years in which to work. But we’ll come back to men and women once we’ve considered another more general point. We are now ready to begin asking some serious questions about sex and sexuality.

Question 1. How do we choose our mates?

Evolution isn’t only about survival of the fittest (which itself doesn’t survival of the strongest, or healthiest – “fit” in this sense means suitable or most fitting to the environment). Not just natural selection, the weeding out of the least fit, but sexual selection plays an important part. The price for sex (no we’re not still talking about rent boys and hookers) is that by reproducing sexually, I only get to pass on half of my genes. So I need to be pretty careful that my super-duper genes aren’t being dragged down by your inferior ones. Thus we get careful choosing of mates, display behaviour and phenomena like peacock’s tails. A peacock doesn’t need an elaborate tail for its own survival – quite the reverse, they are cumbersome and cost energy to maintain. But a peacock who can sustain this preposterous plumage must be, in general, a superior specimen, blessed with a robust constitution, excellent health and fitness and bags of stamina, at least some of which may be genetic in origin. Thus a discerning peahen who prefers to mate with the larger-tailed gentleman will find more of her genes in the next generation, whereas those who seek out the tiny-tailed may discover that the next generation is bereft of her genetic bounty since her offspring suffered from the same lazy attitude, heart condition or inherited disease as their dad.

Note that none of this is mentally considered by the peahen. It is simply a fact that because peahens who prefer to mate with big-tailed males have a greater genetic influence on the next generation, so  necessarily, the next generation contains a higher percentage of peahens who get turned on by big tails.

Quite obviously, even as sophisticated adult humans, with all our language and culture and technology, we also have mate preferences that we didn’t decide for ourselves, but simply woke up with aged about 10. And while it (once again) isn’t true that there is a single monolithic standard of beauty or attractiveness, patterns do emerge and so Marilyn Monroe is generally feted for her beauty whereas Bella Emberg received such compliments less frequently.

But even if we ignore the problem of establishing a global standard for attractiveness, we can still accept that people tend to rate people they meet in terms of how attractive they are – and we need not limit ourselves to physical beauty. A potential mate may strike you as attractive because of their power, charm, vulnerability, sense of humour, kindness, personal wealth, liking for adventure, exotic accent or any one of a number of other reasons. But, if forced to, you could give any person of the appropriate sex whom you happened to meet a rating on an imagined desirability scale. So if you should want a global measure, you can think of this as the average across all potential mates.

Sexual selection tells us that in the game of mating, those whose combined desirability scores are the highest are going to be those who most influence the next generation’s gene pool, and so evolutionary theory tells us that behaviour which tends to lead to this outcome will be selected-for and so come to dominate. That leads us to…

Thought experiment 1. The ice rink

You are one of twenty players (sexes are not relevant for the purposes of this game) who will shortly be let loose on an ice rink. It doesn’t have to be an ice rink, but freedom of movement is key. Each of you wears a number on your back, allowing you to be ranked in order from 1 to 20. Numbers have been assigned randomly and secretly, so – although you can see clearly what number somebody else wearing, you cannot see and do not know your own designation.

The game is to find someone who will agree to leave the ice-rink with you, holding your hand, and the aim is for each pair to attempt to maximise their combined score. So a 9 who leaves the rink holding hands with a 5 will score 14, but will be beaten by an 8 who leaves the rink holding hands with a 11. You can change your mind as often as you wish and the time limit is fairly generous so no-one is making any snap decisions.

The game begins. What is your strategy? The obvious (and correct) strategy is to immediately start looking for number 20. Regardless of what number is on your own back, nothing will give you a higher score than leaving with number 20 in tow. Pretty soon number 20 is spotted and quickly has a great many potential partners. There’s a 1:20 chance in fact that this will be you. So let’s assume it is – you are busily looking out for number 20 when you gradually realise that everyone else has come looking for you. You are number 20! Who are you now looking for? Well, the best score you can possibly get will now be 39, provided you can find number 19. So number 19 now becomes the only person whose hand you are willing to hold. 19 eagerly agrees to hold your hand, and you both happily leave the ice rink having won the game. But the game isn’t over yet.

Once 19 and 20 are paired off, all attention naturally switches to number 18, who is now the best prize available. Number 18 will now only accept the advances of number 17, and so on. By starting with the rule “maximise your combined score” we end up with everybody pairing up with the closest number to them.

Answer to question 1. People choose as their mate the most attractive person who will accept them.

Again, “attractive” is assumed to have a multiplicity of meanings, but this complexity doesn’t change the fact that we find some people more “attractive” than others – even if we couldn’t give a very satisfactory definition of “attractive” even when asked. And because we both seek and select, we reject people if we think we can do better, but set our sights as high as we dare. In life, unlike in the ice rink game, we get a sense of our own level of attractiveness (even if, or especially if, this changes over our lifetime) and so don’t bother approaching those way out of our league because the risk of rejection is suicidally great. When we encounter pairs who appear to buck this trend, they tend to be figures who attract startled comment. “What does she see in him?” and so on. This is precisely because they are outliers and not the norm.

Preparatory notion 3. Game theory can help us understand human psychology

Evolution finds solutions that “work”, where “work” in this sense can be taken to mean “increases the representation of those genes in the gene pool of the next generation”. Evolution in this sense is circular. Natural selection means survival of the fittest. What does “fittest” mean? Those who tend to survive. But if a subtly different shape of fin, a different trade-off in heart construction, or a thicker, shaggier coat creates a survival advantage, then over generations, a population of organisms will shift in that direction. Evolution tests countless tiny variations on the currently best designs and – especially if the environment changes – discards the ones which don’t help and retains the ones that do. It isn’t guaranteed to find perfectly optimal solutions, and if the environment changes very rapidly then evolution may not be swift enough, but when it works, this is how it works.

In just the same way, when it comes to sexual selection, evolution can generate variations on brain construction which give rise to different psychologies which give rise to different strategies. Those strategies which tend to maximise inclusive fitness – in other words those which don’t only aid survival for this individual organism but which contribute to their ability to genetically dominate future generations – will be selected for. But note that even homo sapiens is not granted a psychological makeup which is explicitly and consciously focused on inclusive fitness maximising. If it were the case that, for example, men were consciously focused on maximising their genetic representation in the next generation, that most men would be ferociously keen to donate to as many sperm banks as possible as often as possible – but this is not a solution which evolution could plausibly find. We would expect men to enjoy orgasm however, and this they generally do.

Of course, sex and reproduction is only worthwhile if you live long enough and so other forces come in to play. Some male mammals (although no females as far as I know) will eat their own young if food is scarce. The calculation (not performed consciously of course) is that if I eat my kids today, I can father lots more offspring when there’s enough food to go around. But if I don’t, I’ll die now leaving only this litter, who will probably die themselves. Layered on top of all of these evolved, primal, psychological forces are more recent, subtler drivers such as the need for acceptance, social status and so on, not to mention a whole other wealth of cultural, societal and fashionable forces which also act upon us, and all of that is without even mentioning all of the personal preferences which make us unique.

But game theory – the mathematical study of what tactics are most likely to lead to success given certain rules to play by – can certainly be employed to allow us to discover how evolution might have shaped this part of our mind. We can then look at human societies and behavioural norms and come to some conclusions about how many of these primal needs are preserved, and how many are muffled or eradicated altogether.

And here we must – for the first time – start considering men and women differently, instead of considering evolution, psychology, mate-selection and sex-differences simply as phenomena.

Question 2. What is a man’s best mate-selection strategy for maximising inclusive fitness?

Since the mind evolved, and since the mind evolved under this kind of selection pressure, we can be fairly sure that most men will be seeking a mate who is the most attractive person who will accept him. But maximising inclusive fitness doesn’t only mean finding a life partner. The potential cost of sex to a man is very little. He will never have to bear the child through pregnancy and the time which elapses between conception and birth may very well mean that he is no longer conveniently at hand to raise the child, or possibly no longer identifiable as the genetic father. But like a gambler with an unlimited bankroll, there is no reason for him not to keep rolling the dice again and again and again. Given the choice between having sex with number 18 and having sex with number 11, regardless of what number is on his own back, he would prefer number 18. But he’ll cheerfully have sex with number 11 if no-one else is around.

For men, promiscuity makes sense. Why would you not have sex whenever possible, provided you are still eating enough and providing a decent enough shelter to ensure that you will still be fit and healthy enough to have more sex tomorrow? There is no cost and from an evolutionary point of view, it’s an easy (and fun!) way to out-compete less eager rivals.

Not only that, but it’s also easy to see why men would prefer to have lots of sex with lots of different partners, rather than settling down with just one straight away and raising a family. All that time spent looking after your first child is time you could be spending anonymously fathering dozens more.

Question 3. What is a woman’s best mate-selection strategy for maximising inclusive fitness?

For women, however, the picture is vastly different. There is a tremendous potential cost for a woman in having sex with a man. This cost is twofold. Firstly, if she becomes pregnant, she will have six-nine months of discomfort, followed by many years of expending energy in childcare (this is a potential cost for a man too, as mentioned, but an all-but guaranteed cost for a woman).  The second cost is more subtle. Gestating this baby is a missed opportunity to gestate the baby of another man. Thus, because she wants her genes to be given the best possible advantage in the next generation, she will strongly prefer to have babies only with the most attractive men available.

Now, this is all very well if you are number 20. You simply wait for number 19 to come along, refuse to have sex with him until you have some way of forcing him to stick around and share the burden of childcare with you and give birth to a series of prodigious wonder-children.

But what about the rest of the population? You might imagine that the ice-rink experiment teaches us that number 12s just have to settle for living with and raising children with number 11 or number 13, but a better strategy exists for the female of the species. The possible lack of certainty about paternity here works in the woman’s favour. The very best strategy for all but the most desirable female is to find the most attractive male who will accept her, and then get him to help bring up the child which she gives birth to after having had sex with a much more attractive man.

Question 4. What evidence do we see of this in the modern human world?

This trio of observations – men and women each seek the most attractive person who will accept them, men favour promiscuity over a stable relationship, women need both a helpmate and a genetic mate but they don’t have to be one-and-the-same – unlocks a tremendous amount of human sexual activity, even though almost nobody actually gives totally free reign to these desires. From these observations we should expect to see – and do see…

  • Men are more likely to have multiple sexual partners, and will resist being “tied down” when still young and studly.
  • Women will be much more choosy about with whom they have sex and will be looking for life partners from a much younger age
  • Men will be very concerned about paternity and feel extremely threatened if it is suggested that the baby they are cradling might have been fathered by another man, unbeknownst to them.
  • Both sexes will be concerned about the possible consequences of infidelity on the part of their partner, but each will be concerned about different outcomes. Men fear cuckoldry. Women fear abandonment. As Steven Pinker puts it, women who discover that their man is cheating think “he’s having sex with her – oh god, what if he’s in love with her!?” whereas men who discover that their woman is cheating think “she’s in love with him – oh god, what if she’s having sex with him!?
  • Men, who are briefly deciding where to deposit their sperm before moving on to the next conquest, will tend to make the decision about on whom to bestow their genetic gift on the basis of factors which can be assessed quickly – chiefly physical appearance. Women, who are deciding at their leisure with whom to attempt to form a pairbond, will tend to weigh up a wider variety of factors before they commit to a sexual liason, including (but not limited to) trustworthiness, resourcefulness, kindess and so on as well as physical beauty.
  • And – as Stephen Fry noted – we should expect to see, and do see that gay men, genetically predisposed towards promiscuity but not having to play the mating game with women, will tend to be very promiscuous (despite the fact that no offspring will ever result from this behaviour).

Objecting that these behaviours are cultural rather than genetic misses the point three times. Firstly, it is surely not a coincidence that the biases we would expect to see thanks to evolution exactly coincide with our current cultural biases. Secondly, it entirely skips over the question of where these cultural biases come from.

Maybe because of these two (and I’ll come to the third in a moment) some who took offense at what Fry had to say simply deny that the behaviours listed above are remotely commonplace. Now, I’m not offering any particular evidence that they are, but they resonate profoundly with how men and women are depicted, talked about and represented. Offering a handful of outliers – as discussed earlier – does nothing to provide evidence that these very, very familiar behaviours are, on the contrary, vanishingly rare. It only offers evidence that they are not the totality of human behaviour. Fine. Nobody ever said they were.

And nobody ever said they were desirable either, which is the third way in which taking offense at Stephen Fry’s remarks misses the point. Simply because these behaviours are commonplace doesn’t mean that we should be happy with them, blithely accept them and even if we don’t like them, shrug our shoulders and say “there’s nothing we can do – it’s genetic.” Genetic tendencies are not implacable predestinations. They are powerful forces, but other forces certainly exist, and as thinking creatures with the capacity for abstract thought, rationality and selflessness, we can ask ourselves what kind of society we would like to live in and do what we can to bring that about.

And so, in many Western societies, attitudes – especially straight male attitudes towards women – are profoundly shifting away from what might be expected given these primal, evolutionary forces; but the shift is not, and I doubt ever will be, so complete as to eradicate any meaningful difference between the sexes. If you doubt that these evolutionary forces still act on our unconscious desires and behaviours, then consider this elegant study (sorry, no citation).

Researchers interviewed, took photographs of and took blood tests from a number of young women in nightclubs. From the interviews, they determined whether the women were single or in a stable relationship. From the photographs, they measured how much bare skin they were exposing as a percentage. And from the blood tests, they determined where they were in their menstrual cycle. The results were a strong correlation between fertility and skin exposure. The more likely they were to conceive tonight, the more flesh was on display. Their relationship status was almost irrelevant.

In all likelihood, not one of these women is making a calculated, rational decision to expose more skin tonight for this reason, and women being choosy in the way they are and for the reasons they are – both discussed above – even those dressed most provocatively may have failed to find anyone worthy to go home with, but this study does show I think at least one way in which our evolutionary legacy continues to influence our behaviour, whether we know it or not.

In a later post, I’ll explain why science can prove that there’s no such thing as bisexuality and why women genuinely don’t know what they want. If that doesn’t get you cross, then nothing will.