How did we get where we are, we human freaks of nature? Language, rational thought, art, science and technology set us apart from other species. Add to that list (more curse than accomplishment) an acute awareness of our own mortality. Other animals show faint glimmerings of innovation – crude tool use, for example – but no other species has so much as invented a fork, let alone a bicycle or a nuclear power plant. Something happened in the evolutionary history of Homo sapiens to cause an explosion of ingenuity orders of magnitude greater than anything seen in other species, including our big-brained cousins the Neanderthals. But what? And when?

According to Simon Baron-Cohen, the gates of human invention opened between seventy thousand and a hundred thousand years ago. The key was the evolution of a brain system – he calls it the ‘Systemising Mechanism’ – that caused a radical shift in our ancestors’ understanding of the world. Instead of looking at objects and events as isolated elements of experience, the mind could now conceive of them as components of a system, using recursive if-and-then patterns of thought (deploying the terminology of the 19th-century logician George Boole). We had grasped the concept of causality. The engine of invention was turning and Homo sapiens had broken free from a seeming eternity of hominin creative stagnation, during which the design of primitive hand axes had scarcely altered in well over a million years. It was just a matter of time before we split the atom.

This great cognitive leap forward did not, as rival theories contend, depend upon the emergence of language, although once the fires of invention had been kindled language acted as a powerful accelerant, facilitating if-and-then reasoning by allowing us to articulate and manipulate new ideas. Even then, the Systemising Mechanism would not have gained full force without the evolution of yet another game-changing brain system unique to modern humans, the ‘Empathy Circuit’. If-and-then reasoning was well suited to analysing relatively static features of the physical environment, but it was ill equipped to cope with the dynamics of social interaction. This was a job for the Empathy Circuit, with its two distinct subsystems: cognitive empathy (imagining the thoughts and feelings of another) and affective empathy (responding with appropriate emotion to others’ thoughts and feelings). Together they formed bridges between minds and, consequently, enabled a commerce of new ideas.

The Pattern Seekers is part grand narrative of the evolution of the human mind and part synthesis of Baron-Cohen’s previous writings on autism. The two are linked in the bold claim that ‘the genes for autism drove the evolution of human invention’. Furthermore, he argues, those same pattern-seeker genes continue to propel inventive thinking in the modern era. We are each, to varying degrees, ‘empathisers’ (good at understanding people) and ‘systemisers’ (better attuned to impersonal, ruled-based systems). Roughly a third of us have stronger empathic skills relative to systemising abilities, and another third show the reverse pattern. For most of the rest, the two aptitudes are balanced. But there is a minority of people who have extreme leanings towards one while lacking aptitude in the other. ‘Hyper-systemisers’ – extreme pattern seekers – are strongly drawn to STEM subjects. Some may enjoy spending their time simply and unproductively absorbed by, say, the patterns and subtle variations of washing-machine cycles. An elite few – Thomas Edison is held up as an example and discussed at some length – are blessed with genius. Citing his own studies, Baron-Cohen notes that many autistic people are predisposed to pattern seeking while hyper-systemisers in the general population often display autistic traits, leading him to conclude that they share the same kinds of minds.

The evolutionary thesis, Baron-Cohen writes, revolves around ‘those three little words – if, and and then’. A great deal therefore hangs on the claim that if-and-then reasoning is unique to modern humans. Evidence that some other animals are capable of it is considered but rather lightly dismissed, though it seems to me that some of the cited examples of tool use and invention among dolphins, primates and crows suggest forms of intelligence well in advance of simple ‘statistical’ or ‘associative’ learning, which is how Baron-Cohen explains them away.

Palaeoanthropologists might also point to evidence of if-and-then thinking in archaic humans. There are abundant signs of hearth building for the controlled use of fire from around four hundred thousand years ago, well before the appearance of modern humans. The construction and fuelling of large hearths would involve levels of planning and coordination that would almost certainly have required some degree of if-and-then information processing. The same could be said of the Neanderthals’ construction of composite spears and their use of them in coordinated hunting expeditions.

I think it’s fair to say that the jury is out as to whether archaic humans were capable of at least the rudiments of if-and-then thinking (likewise for present-day chimpanzees and some other animals), but the theory does not really stand or fall on the ‘three little words’ by which Baron-Cohen sets such store. Elsewhere, he makes the more conservative, and I think justifiable, claim that only humans possess the ‘full’ Systemising Mechanism, the engine that drives ‘the curiosity to ask questions and to experiment with variations in patterns’. Repeated experimentation is what counts: question, hypothesise, test, modify.

It’s doubtful, as the author acknowledges, that a single genetic mutation accounted for our cognitive sea change. It’s more likely that ‘hundreds if not thousands of common genetic variants’ were involved, and polygenic traits typically evolve gradually, not abruptly. The prehistoric ‘cultural explosion’ is usually dated to around forty thousand years ago on the evidence of the profusion of cave art, ceremonial burials and symbolic artefacts around that time. This is the date the archaeologist Steven Mithen gives for the emergence of the modern mind in his influential book The Prehistory of the Mind. It is markedly later than the date of Baron-Cohen’s ‘cognitive revolution’. Perhaps rather than a cultural explosion, it was something more akin to the blooming of a flower that had been many millennia in the growing and was seeded in the era identified by Baron-Cohen as the dawn of if-and-then thinking. Our ancestors’ brains had evolved to the size of modern brains by then and, in terms of gross anatomical structure, would have been similar to ours. The difference between our brains and theirs comes down to software, not hardware. There may not have been much gross anatomical change down the millennia, but the brain’s functional architecture reconfigured itself (and consequently the emergent mind) in response to social and environmental pressures, and quite probably continues to do so.

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Some palaeoanthropologists will be wincing at the audacity of Baron-Cohen’s thesis. The arguments presented in The Pattern Seekers are, broadly speaking, neuropsychological and the brain circuits underlying both systemising and empathy are mapped out in some detail. A slew of new research methods have encroached upon the traditional ‘stones and bones’ territory of archaeology in recent decades, sometimes with radical effects. Notably, since the 1980s, molecular genetic studies have brought about huge revisions in hominid taxonomy. But taxonomy is one thing and neuropsychology is quite another. We may be able to discern some facts about the size and shape of the brain from prehistoric skulls. There are even ways of deducing information about functional brain asymmetry (evidence of tool construction and use indicates that our archaic forebears were predominantly right-handed). But, ultimately, when it comes to the big questions concerning the origins of language and thought, the evidence is indirect, leaving plenty of scope for fanciful inference.

After speculating on the role of the ‘autistic’ mind-set in the prehistoric genesis of invention, Baron-Cohen turns in the final chapters to the present and future circumstances of autistic individuals. Our understanding of autism has altered radically over the past thirty years or so and Baron-Cohen has played a significant part in that scientific and societal reorientation. He argues that society could still do more to accommodate and nurture autistic people, and he cites some enterprising examples in that direction: for example, Unit 9900 of the Israeli army was set up to harness the attention to detail and pattern-seeking talents of autistic people going through military service. Autism, we now understand, covers a broad spectrum of aptitudes, talents and limitations. Some autistic people have severe intellectual disabilities while others have superior intelligence, something that reveals itself most clearly in technological fields, and autism is increasingly thought of in terms of difference rather than disability. Rising rates of autism are the result of a variety of factors, including greater awareness of it, revised diagnostic criteria and the reconceptualisation of autism as a spectrum condition. Another reason, Baron-Cohen suggests, stems from the growth of ‘technology hubs’: Eindhoven, Silicon Valley, Silicon Fen, MIT and Hyderabad, among others. Hyper-systemisers and autistic people often thrive in such environments and, as like-minded people, frequently pair up (‘assortative mating’). There is a significantly higher chance of their offspring being autistic than in the general population.

‘We might say that humans’ greatest invention was the invention of invention itself,’ the philosopher Keith Frankish has written. The Pattern Seekers makes some provocative speculations on the neuropsychological origins of our ingenuity. You don’t have to accept Baron-Cohen’s thesis in its entirety to be stimulated by the bold idea that major historical shifts in brain function are a central strand in the story of human evolution.