Unthinkable
- By Helen Thomson, John Murray, 304 pages, £20
In the early 17th century, a French adolescent claimed to have eaten more than 50 children, because he was a wolf with a fierce appetite for raw flesh, especially that of little girls, which was “delicious”. Naturally he was condemned to be hanged and burnt, but doctors diagnosed “a malady called lycanthropy, induced by an evil spirit”, so instead he was confined to a monastery.
Such fun facts are what make popular science popular. Helen Thomson’s first book, a study of six interesting brains, has a ready supply of them, and she is good at giving them context. Clinical lycanthropy, she explains, as opposed to the kind featured in The Twilight Saga, is extremely rare.
Jan Dirk Blom, of the Parnassia Psychiatric Institute in The Hague, has found only 13 cases recorded over a period of 162 years; there have also been reports of people thinking that they have turned into dogs, snakes, a hyena, a frog, even a bee.
To explore the wilder aspects of neurology, Thomson spent two years travelling the world “to meet people with the most extraordinary brains”. Before presenting her results, she offers some brisk history.
For a long time, the brain’s purpose was unclear. The ancient Egyptians, for instance, believed that the mind lived in the heart, which they preserved before mummification, discarding the brain.
Plato thought the organ might house the soul, but his contemporaries were unconvinced. His pupil Aristotle argued it was the heart that contained the mind, and that the brain was merely a cooling system, to temper the heart’s “heat and seething”. Galen, the second-century physician, discovered the four cavities of the brain, later termed ventricles, and concluded that the soul floated around them, passing into “animal spirits” that were pumped around the body.
Galen’s view went uncontested until the 17th century, when Charles I granted Thomas Willis permission to dissect criminals sentenced to death in Oxford; he became “addicted... to the opening of heads”, and invented “neurologie”.
In the 19th century, the German anatomist Franz Joseph Gall identified areas he thought responsible for poetry, murder and so on. Some of them were accurate — an “organ of mirthfulness”, for example, towards the front of the head. Modern neurologists have stimulated that area and found that it makes patients laugh.
Thanks to MRI, EEG and Cat scans, “we now know that there are 180 distinct regions that lie within that three-pound lump of tissue that throbs and flutters within our skulls”. The thalamus relays information between those regions, as neurons send electrical impulses, each forming connections with its neighbours. If all the connections were counted at the rate of one a second, it would take three million years to complete.
The mind, Thomson explains, “arises from the precise physical state of these neurons at any one moment”, and it is “from this chaotic activity that our emotions appear, our personalities are formed and our imaginations are stirred”. This sounds like a fudge and she goes on to allow that “none of what we call our ‘higher’ functions — memories, decision-making, creativity, consciousness — are close to having a satisfying explanation”.
Another problem is that the extraordinary brains she encounters tend to be a bit underwhelming. Her search for a lycanthrope, for example, takes her to Abu Dhabi, where she meets Matar, who thinks he is a tiger. Matar experiences strange pains in his limbs, growls alarmingly, fears he might eat someone, and once tried to bite a barber. And that’s about it.
Each case, though, prompts her to survey past and current scientific opinion, and to supply arresting anecdotes. In America, she meets Bob, a television producer who can remember every day of his life, all the way back to feeding at his mother’s breast. Bob is apparently an HSAMer, as people with highly superior autobiographical memory are known, due to “an enlarged caudate nucleus and putamen”, whatever those may be. This must be appalling for Bob, and to compound his tragedy it also makes him a bit of a bore.
She meets an American called Sharon, who is permanently and hopelessly lost, probably because of impairment to her entorhinal cortex, which supplies information about where we are in relation to boundaries, and her retrosplenial cortex, which is dedicated to the recognition of landmarks.
Thomson considers the atrophying effect of GPS on our navigational skills, and tells the story of a Belgian lady who set out on the 38-mile journey to her home in Brussels, entered the wrong address in her GPS, and turned up obediently two days later in Zagreb.
In Bilbao, she meets Ruben, a journalist who experiences synaesthesia, the blending of the senses, and, although colour-blind, sees coloured auras around people.
Ruben’s case reminds her of Vladimir Nabokov’s exquisite sensitivity to letters: “The long a of the English alphabet... has for me the tint of weathered wood, but a French a evokes polished ebony... In the brown group, there are the rich rubbery tone of soft g, paler j, and the drab shoelace of h.”
Some of Thomson’s observations are rather ordinary. “Have you ever watched a painful tackle on the football pitch,” she inquires, “and felt a twist in your stomach, or felt sad at the sight of someone upset? If so, you have experienced empathy.” Well, I never. Others seem dubious. Do we really have “the ability to remember an infinite amount of knowledge”?
Still, there is much of interest here, especially in her chapter about hallucinations, in which she pays tribute to Oliver Sacks’s brilliant book on the subject (Hallucinations, 2012). She meets Sylvia, a retired British teacher who has been deaf for a decade yet constantly “hears” music, a compensatory hallucination similar to the “seeing” of the blind.
The brain makes predictions based on experience, and only “if a prediction is wrong does a signal get passed back to higher areas, which adjust subsequent predictions”.
So it may be that, as Anil Seth, of Sussex University, puts it, “Our reality is merely a controlled hallucination, reined in by our senses.” Thomson agrees. Hallucinations are not only common, she argues, but “vital to producing our perception of reality. So vital, in fact, that you’re probably hallucinating right now”.
–The Telegraph Group Limited, London 2018
