Increasingly, with the rapid growth in the number of people diagnosed with Alzheimer’s and other kinds of dementia, the journey towards the end of life is presented as a battle we ought to be spared. After a period of denial about a poorly relative, people might only get a crash course in reality at A&E when the doctor pulls them to one side and asks in confessional tones, “Have you considered a Do Not Resuscitate notice?”
But the prognosis for old age need not be so stark, argues Daniel Levitin, who begins his study of the ageing brain with the poet Dylan Thomas’s musings on death and his command to his sickly father to, “Rage, rage against the dying of the light.” Nonetheless, The Changing Mind is not a defiant call to arms that casts old age as an occupying force that will inevitably barge into all our lives. Rather, it is a manual for living.
The subtitle, “a neuroscientist’s guide to ageing well”, hints at the cautious optimism evident in Levitin’s use of elderly outliers. Two of the most sprightly are Julia “Hurricane” Hawkins who at 102 set a world record for age-100+ sprinting when she ran 60 metres in 24.79 seconds, and the master cellist Pablo Casals, who, when asked why at the age of 80 he kept practising, answered, “Because I want to get better.” But exceptionalism surely only proves that the best most people can hope for in old age is that things will get worse, “but more slowly”.
Levitin is particularly exercised by how the intersection of the social world and our genes impacts on our personalities. Pressingly, why do some elderly people retain their interest in discovering new things? One active area of research focuses on the connection between novelty-seeking genes and dopamine regulation. The loss of dopamine is often identified in numerous neurological symptoms that present with old age.
Drawing insights from developmental neuroscience and individual-differences psychology, Levitin attempts to challenge received notions of the incremental deficits that accompany the ageing brain, by offering a seductive alternative narrative. It’s now known, for instance, that the brain is “plastic”; following injury, it can rewire itself to compensate for lost functionality. But “plasticity” is also a feature of the ageing brain. Levitin reconnects old age with wisdom, since, as we age, our brains become better at pattern matching and abstraction “to extract common points from prior experience… to make predictions about what is likely to happen next”.
Wisdom, of course, is dependent on memory, and Levitin reminds us of the importance of recall in determining our sense of self. He reflects on research first conducted by Frederic Bartlett in the 1930s about the unreliability of memory. Retrieving memories is an active process that subtly changes the remembrance of an incident with each renewed recollection.
The Changing Mind is a hybrid of dutiful academic writing and popular science, but one of its strengths is the use of cultural references to illuminate its truths (invoking the emotional trigger of remembrance, for instance, in Joni Mitchell’s songs). The science behind the faultiness of memory underscores what has often been movingly rendered by novelists. In William Maxwell’s So Long, See you Tomorrow, for example, the protagonist, struggling to distinguish a memory of an experience from the recollection of a photo associated with it, concludes: “in talking about the past, we lie with every breath we draw”.
But why do the elderly find that some memories are easier to retrieve than others? At the highest level memory is divided into implicit (for example, remembering how to play an instrument without thinking about it), and explicit (memories, including those which are episodic, resulting from a particular incident “imprinted with an emotional resonance”). In the brain the medial temporal lobe, and particularly the hippocampus, are crucial for forming some kinds of explicit memory (but not for implicit memory), and it’s these regions that decay and shrink with age and Alzheimer’s. This is why a disoriented elder might not remember you but can still play the piano.
Old age is inevitably accompanied by a general slowing of cognitive function – caused by the thinning of the protective myelin sheaths that surround axons or nerve fibres, leading to disturbances, misfiring and slowing in thought transmission. There’s a further assault from the accelerating shrinkage of brain volume; critically, the first areas in line for the reduction are the prefrontal cortex and hippocampus, which may account respectively for unexpected and uncontrolled emotional outbursts and an inability to keep track of “butterfly thoughts”.
As we cross into our forties, Levitin points out, “Our brains spend more time contemplating our own thoughts vs taking in information from the external environment.” Cognitive reserve – from the benefit of more education and intelligence – can “insulate against the damaging effects of ageing”. But what else can be done? The news is not unremittingly bleak. We can eat more fish, or at least include essential fatty acids in our diets. But there’s no point relying on the kind of brain training touted by advocates of sudoku; all sudoku improves is your ability to play sudoku. Levitin does, though, make a case for the benefits of virtual learning – that the immersive experience of virtual reality can transport and possibly prepare you for unimagined futures.
His numerous discursive passages essentially reinforce the same message: free yourself from whatever stops you trying new things. By which he means, quoting the psychologist Carol Dweck: “Accept those [inhibiting] thoughts and feelings and work with and through them.”
The occasional tonal shift of The Changing Mind towards a self-help guide may seem a poor fit for those more inclined towards the brutality of fact evident in Leonard Cohen’s reflections on old age: “a million candles burning for the help that never came”. Cohen’s description resonates, I imagine, with many elderly people who are increasingly ignored by relatives who see the little reward from attempting to communicate with them. But in this passionate and intelligent study, Levitin offers hope and argues that no one need “go gentle into that good night”.
Colin Grant is the author of “Homecoming: Voices of the Windrush Generation” (Jonathan Cape)
The Changing Mind: A Neuroscientist’s Guide to Ageing Well
Penguin, 528pp, £18.99
This article appears in the 26 Feb 2020 issue of the New Statesman, The death of privacy