Progress, Laughter, Sex – But not in that order

By Will Catton

Funniness has played a far more powerful role in human evolution than anyone seems to realise. Transcending cultural boundaries, laughter is innate (though not unique) to humanity: children born blind and deaf will smile and laugh in response to pleasure.1,2 And joking surpasses even music as our most ubiquitous art form. In this 2,999-word essay, I’ll argue ‘wildly’ that evolutionary progress is real. I’ll then describe why humankind represents an evolutionary revolution, a fundamentally new stage in life’s unfolding story, and how that unique trigger of human laughter – the joke – illustrates the unprecedented set of forces that propelled our animal ancestors down the path that has led to us.

The discovery of our true place within the tree of life has been called a completion of the ‘Copernican revolution,’ shifting humanity still further away from the centre of the universe.3 But “Darwin’s dangerous idea” can’t really be blamed for a downward zig of our zagging zeitgeist.4 As recently as 1947, Julian Huxley (Aldous’ older brother) wrote the popular book “Evolution in Action,” which defined ‘evolutionary progress’ as change “leading life into new regions of evolutionary opportunity,” and argued with enjoyable exuberance that humanity’s arrival is a brand new stage of evolutionary progress: the latest big step in cosmic history.5,6

Adrift now, but somehow still smug, we wryly raise an eyebrow at such grandiose claims. Huxley’s ‘progress,’ we’ve been taught, is nothing more than the lingering stain of Victorian prejudice.7 This sentiment climaxed with the late Stephen J. Gould, when he argued that the only reason life’s complexity has increased at all is a random drift away from the impenetrable wall of simplicity where life began: Release smoke next to a wall, and the smoke will drift away from the wall, even if there is no breeze.8,9 Such thinking has gained a considerable degree of traction: to talk of biological progress is today highly unfashionable in academic circles.

“All the more reason to do so,” came the rallying cry from the eminent naturist Edward O. Wilson.10 But the silence stayed deafening: Try searching the index of a recent evolution textbook for the word ‘progress’.11,12,13 Even ‘complexity,’ though safer, is rare. Evidently, this taboo runs surprisingly deep.

‘New clothes’? That Emperor looks like he’s due for a wax.

One reason ‘progress talk’ is so deeply distrusted is its ring of the world straining toward some ultimate goal. Such teleological thinking, which appeals to an ends-oriented purposefulness in the material world, has long been discredited in biology: evolution doesn’t plan ahead.14 Now if anyone were insisting that progress should be defined as “increased resemblance to humankind,” this criticism might stick. But what if we follow Huxley, and define progress as a gradual increase in complexity, equipping organisms to face a growing portfolio of scenarios – and crucially, paving the way for further such growth? Then progress, in many lineages, is surely undeniable; and any account of evolution will remain incomplete, until it satisfactorily answers the simple question: ‘why?’10

With each successive generation of life on earth, it becomes ever more fantastically amazing that every ancestor of the current generation, all the way back to the very dawn of life, has made it safely through to reproduction. It was Darwin’s genius to realise that this amazingness was so amazing that it could account for another fantastic amazingness – the amazing degree of structure and adaptation abounding throughout life.15 To grasp the scale of that first amazingness, just think: in a very real sense, you are about 1,000,000,000,000 days old. Since its first moments on earth, the spark of life has been passed continuously for that long, by your ancestors, down through your family tree. Your ancestors possess an unimaginably perfect track record: they’ve navigated the myriad perils of the world, flawlessly acing that defining test of life – of survival through reproduction – for a trillion days straight.16 Don’t underestimate the scale of this number: one trillion piled-up possums would overflow literally thousands of sports stadiums. It’s even more than the record-year U.S. trade deficit, in U.S. dollars.

Past organisms whose descendents didn’t make it, Darwin realised, stupendously outnumber those whose did.15 Success in the face of such overwhelming odds required an immense amount of luck. And some of this luck consisted of chance hereditary advantages that helped your ancestors to succeed. The gradual accumulation of these advantageous variations is evolution by ‘natural selection’. Biological progress seems unsurprising when natural selection is looked at in this light, when we focus on the stunning evermounting amazingness that the organisms of the day have actually made it. Of course this increases with time!

To be sure, if you track the fate of any particular lineage, nothing can guarantee that what’s helpful in the short term won’t prove harmful in the long run – witness the elegant engineering behind the world’s nuclear arsenal, or the the fate of the flightless birds of these very islands.17 But if you follow the whole tangle of lineages on a longer timescale, you’ll find that the successful lines are generally those whose past changes appear advantageous now – those that appear to have progressed. (Give up those silly dreams: your descendants will never be daffodils.) This is really just the principle of natural selection once again, applied on a larger scale. But it includes that familiar ‘commons tragedy’ of innovation called the arms race.18 Once nature has hit upon a truly useful innovation, and has then ‘diversified its portfolio’ by passing this innovation to multiple descendant-species, it’s likely to stay: lines that ‘cooperate’ by losing the innovation lose out to lines that ‘cheat’ by retaining it. (Anyone not already familiar with the tragedy of the commons, amidst today’s simmering climate of competition for any available oil “production” capacity, is encouraged to look it up.)18

The evolutionary arms race illustrates another principle that surely underpins evolutionary progress: that life itself contributes crucially to the forces driving evolution. As life has gained progressively deeper awareness of its surroundings, the selection pressures driving biological evolution have become more dynamic and more aware. Natural selection ceased to be an unconscious force, as soon as living things acquired a mind. It ceased to be blind, the moment life acquired eyes. This fascinating insight has recently been invoked by Andrew Parker to explain a perplexing singularity that exists in the fossil record: the so-called ‘Cambrian explosion’.19 The unprecedented, richly diverse layer of fossils that inspired this name has long mystified palaeontologists. Until 544 million years ago there were just three animal phyla; six million years later, there were 38 of them – mostly quite ugly.

Parker’s proposal is stunningly simple. The Cambrian explosion promptly follows the first appearance of eyes in the fossil record. Just think: before that transition, the world was utterly dark. The emergence of this new sense perception, Parker believes, altered the evolutionary dynamic: A frantic new arms race fanned the surprising spread of armoured fossils seen in the Cambrian layer.19

Now for a seamless transition: from ‘arms race’ to sex. Sex is maintained by much of life, including most plants and animals, even though it doesn’t come cheap (except maybe in Montreal). Let’s be frank: finding a mate takes quite a lot of work. And biologists have long debated the ‘twofold problem of sex’: why waste time with males at all?20 For monogamous species whose males help out around the home, that question loses some of its sting – but clearly sex must have some serious advantages, to balance its undeniable costs. Evolutionary biologists have identified many interesting benefits of sex, besides its being the most enjoyable form of exercise after touch rugby. Sex mixes heredity. This can combine different hereditary strengths in the same offspring, speeding up the process of evolution.21 It can increase the variety of offspring produced in each generation, providing useful dynamism in the face of a changing environment.

But the idea that sex is essentially a way of shuffling genes misses much of its real significance to biological progress. A spicy new source of amazingness was involved in the lives of your sexual ancestors: the amazingness of their each convincing some other ancestor of yours to fandango. The more finicky those other ancestors were, the more impressive this familial achievement becomes. Evolutionary success, for a sexual beast, is tested by the mating choices of the rest of the species as much as by survival. So sex is the species’ biology grabbing the reins on its own evolution.14,22 Such control does create new dangers. Fashion is fickle: the peacock’s tail, just like hammer pants and the ‘hypothetical’ speculative housing market, may well be in for a bumpy devaluation. But the immensely beneficial trade-off is this: a sexual species’ evolution can be directed with all the subtlety of its members’ ability to perceive one another. Sizzling health is nature’s oldest aphrodisiac.

And when this perceptiveness comes to be trained on itself, it can grow explosively – though in life’s history so far, this has happened just once. Before focusing on humanity’s roots as an empathic, creative, culture-driven species, let’s briefly consider our closest nonhuman relatives, the chimpanzees. Chimpanzees are creative and intelligent. Jane Goodall has described watching one chimp, Mike, calmly fetch empty paraffin cans to supplement his charging displays by clanging them together and sending them flying at his rivals.23 Such inventiveness set him apart from the other chimps; it appears to have earned him a faster political ascent than might otherwise have been expected; and with this status, reproductive benefits: the ladies. But there’s an important distinction between Mike’s situation and what’s seen in humans. Mike’s good fortunes stemmed only indirectly from his creativity, through his intimidation of the rival males. Witnessed displays of creativity appear to have no direct effect on the relationships between chimpanzees.23,24,25

To appreciate the uniqueness of the human mind, it’s useful to see how easily we outperform even the wonderful chimpanzee in tasks testing ‘projection’. Imagine a long clear pipe, fixed horizontally. Visible inside is a tasty tidbit, which a toddler or a chimpanzee can easily learn to obtain, by pushing a stick either way through the tube. Such tool use doesn’t distinguish humans from chimpanzees; but what if on one side of the food there lies an opening down into a compartment, so that if the food is pushed that way, it will fall down, and be forever lost to the chimp? It turns out that at this task, chimpanzees fare far worse than three-year-old humans. Compared with just one attempt for the toddler, it takes a chimp hundreds of attempts to learn to push the food away from the trap.26

Even more revealing are their respective behaviours when the apparatus is now flipped, so the trap is above the food. The toddler will push the food either way, understanding that things never fall up: the trap is no longer a threat. Meanwhile the chimp continues pushing the food away from the opening.26 The chimpanzee’s learning appears merely associational, rather than insightful. The chimp somehow lacks the ability to project itself into the role of the food, an ability that comes utterly naturally to a human toddler. The same holds of the empathic projection involved in the ‘joint attentional scene’ required for meaningful teaching, where toddler and adult share an awareness of one another’s attention to a third object.26

Teaching, and the complex culture it permits, sets humans apart. Unlike any other animal, a huge fraction of what each of us knows, we would never have thought of ourselves. Our whole vocabulary, and the grammar that renders it useful, was developed gradually by people before us. So we each embody the collective genius of earlier thinkers – reduced somewhat by their collective forgetfulness.27 To understand our evolutionary origins, we need to learn how we came to be reliable inheritors of our ancestors’ culture. We also need to learn how our ancestors came to be cultural innovators.26 This second shift, which emerged naturally from the first, can be understood from a group’s reaction to a joke, especially from the joker’s elevation in everyone’s eyes, by considering what humour really represents.

Most empirical humour research focuses on humour recognition, rather than on humour production, and doesn’t attempt to pin down precisely what funniness is.1 Fair enough. Freedom and creativity are at the very core of humour, so any attempt to capture it would surely fail. As everyone knows, a plodding explanation of why something is funny is the surest way to flatten the joke.28 But merely describing humour is different from aiming for humour study’s Holy Grail, of stating what’s sufficient for something to be found funny. The genius of comedians such as Chris Rock, Sarah Silverman and Winston Peters is summarised well by their ability to make something seem totally obvious, even though you’ve never thought of it before. This is no accident: In fact, it’s a hint at humour’s evolutionary origins.

Spontaneous laughter lives at the intersection between pleasure and surprise.2 When we laugh at a joke, we’re giving physical expression to our happiness at being surprised by a new idea or perspective. What makes a punch line is usually the unexpected second idea it triggers – though much harder to characterise is the largely culturally-propagated aesthetic determining the joke’s funniness.1 We’re so responsive to unexpected playful ideas, as a species, that they trigger their own automatic inbuilt pleasure response. And with our love of laughing, and of those who make us laugh, we exert a selection pressure that significantly advantages those with the imagination that it takes to be funny. The biological basis of our ability to generate surprising ideas, and the surprisingness of the ideas that we generate, is being driven ever upward.

And our collective love of hilarity is driving this progress forward.

I’m focusing here on jokes, but a similar analysis applies, for instance, to music. Jokes arise from a surprising coherence underlying what is said. Melody, harmony, rhythm, rhyme: each achieves fundamentally the same ‘form,’ but the coherence here emerges from patterns in the sounds themselves. Surprise is relatively more important to humour; coherence is relatively more important to music. This is reflected in the difficulty of remembering jokes, compared with remembering songs. Now, creativity in general has been called the process of “having original ideas that have value”.29 It’s striking how the enjoyment of ‘surprising coherence’ pervading our entire aesthetic experience (but most immediate in the particular case of humour) parallels this definition of creativity, setting us up as highly effective ‘creativity filters’. Surprise demands originality. Coherence is value. And so a love of creativity is intrinsic to what we are.

Culture is alive. Teaching is reproduction: ideas and behaviours are ‘breeding’ from one person to the next. And cultural evolution is itself partially Darwinian.30,14,31,32 What change was required in its substrate – our animal ancestors’ biology – before this ‘life of the mind’ could begin flourishing into today’s rich ‘cultural ecology’? Astonishingly little. The unprecedented, epochal transition came when our animal ancestors evolved a generalised reverence for displays of difficult culture. Their fundamentally new feature was this: social (and procreative) elevation now followed directly, for individuals who exhibited culture that the others found hard. Unlike its utterly surprising consequences, this transition itself should surprise no-one: chimpanzee culture, such as ‘termite-fishing,’ helps the chimpanzees.23

“Social selection” would be a more appropriate name for this force than “sexual selection,” though the two have always been deeply intertwined, since social status and its various benefits are socially mediated. Eddie Izzard brings laughter to millions, earns vastly more than I do, and can afford much better makeup; also better healthcare. Just like Parker’s vision of the Cambrian explosion, our ‘cognitive explosion’ has come from an arms race, driving, and driven by, an ever-deepening awareness of one another. But this unprecedented new struggle, which roils on today, is an arms race between our linked cultural and biological levels. The resulting tension surely helps to explain that sweet agony of human existence.

Here’s how it works: Our culture rapidly evolves to strain on its leash (our biological limitations) since pushing against what’s humanly possible is precisely how people seek to set themselves apart. With their social elevation, and consequent evolutionary rewards, talented individuals drive forward our biological evolution. And our culture, rapidly rising to stretch these newly increased capabilities once again, completes this continuing cycle. The valued skill might be useful (e.g. making tools or fire); competitive (e.g. rulebased ritual conflict – sport); largely decorative (e.g. dancing, joking, cooking, grace). It might be pointless but fun (e.g. outdrinking your boss, and still managing to recite naughty lyrics); it might even be ethical (e.g. resisting the restless impulses of the ego).

As social selection has driven our cultural sophistication forward, its emphasis has shifted away from replicating extant culture, toward creativity: onto cultural innovation. Verbal humour, the epitome of real-time creativity, cannot have emerged until this unfolding process was already well under way. But one funny fact points to its preeminence nonetheless. As is shown nicely by the quote “tickle me!” from a chimp to whom researchers tried to teach sign language,33 play is so crucial to chimpanzee social life that nature has given chimps their own built-in game. Humans are ticklish too, and such is our love of surprising ideas – so important to us, attaining shifts of perspective – that they’ve become linked into laughter: the tickle response.2 Daily we tickle, and are tickled, by one anothers’ thoughts.

We may be an obscure twig in the tree of life, but we’re also utterly unique. We’re the only species we know, whose environment has demanded to be tickled by a stream of surprising new understandings. That other members of the self-same species formed this ‘environment’ is not beside the point. It is the point. The unsentimental processes of nature had given way to our ancestors’ conscious intervention, long before our ancestors ever made empires. We, the world’s funniest, best educated, most outrageously dangerous experiment in creative thought, have been driving our own evolutionary progress: We’ve largely created ourselves.


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