A revolution in our sense of self


Nick Chater writes:

At the climax of Anna Karenina, the heroine throws herself under a train as it moves out of a station on the edge of Moscow. But did she really want to die? Had the ennui of Russian aristocratic life and the fear of losing her lover, Vronsky, become so intolerable that death seemed the only escape? Or was her final act mere capriciousness, a theatrical gesture of despair, not seriously imagined even moments before the opportunity arose?

We ask such questions, but can they possibly have answers? If Tolstoy says that Anna has dark hair, then Anna has dark hair. But if Tolstoy doesn’t tell us why Anna jumped to her death, then Anna’s motives are surely a void. We can attempt to fill this void with our own interpretations and debate their plausibility. But there is no hidden truth about what Anna really wanted, because, of course, Anna is a fictional character.

Suppose instead that Anna were a historical figure and Tolstoy’s masterpiece a journalistic reconstruction. Now Anna’s motivation becomes a matter of history, rather than a literary interpretation. Yet our method of inquiry remains the same: the very same text would now be viewed as providing (perhaps unreliable) clues about the mental state of a real person, not a fictional character. Historians, rather than literary scholars, might debate competing interpretations.

Now imagine that we could ask Anna herself. Suppose the great train slammed on its brakes just in time. Anna, apparently mortally injured, is conveyed in anonymity to a Moscow hospital and, against the odds, pulls through. We catch up with Anna convalescing in a Swiss sanatorium. But, as likely as not, Anna will be as unsure as anyone else about her true motivations. After all, she too has to engage in a process of interpretation as she attempts to account for her behaviour. To be sure, she may have “data” unavailable to an outsider – she may, for example, remember the despairing words “Vronsky has left me forever” running through her mind as she approached the edge of the platform. However, any such advantage may be more than outweighed by the distorting lens of self-perception. In truth, autobiography always deserves a measure of scepticism.

There are two opposing conclusions that one might draw from this vignette. One is that our minds have dark and unfathomable “hidden depths”. From this viewpoint, we cannot expect people to look reliably within themselves and compile a complete and true account of their beliefs and motives. Psychologists, psychiatrists and neuroscientists have long debated how best to plumb the deep waters of human motivation. Word associations, the interpretation of dreams, hours of intensive psychotherapy, behavioural experiments, physiological recordings and brain imaging have been popular options.

I believe, though, that our reflections should lead us to a different conclusion: that the interpretation of real people is no different from the interpretation of fictional characters. If Tolstoy’s novel had been reportage, and Anna a living, breathing member of the 19th-century Russian aristocracy, then, of course, there would be a truth about whether Anna was born on a Tuesday. But, I argue, there would still be no truths about the real Anna’s motives. No amount of therapy, dream analysis, word association, experiment or brain scanning can recover a person’s “true motives”, not because they are difficult to find, but because there is nothing to find. [Continue reading…]

How new data is transforming our understanding of place cells — the brain’s GPS


Adithya Rajagopalan writes:

The first pieces of the brain’s “inner GPS” started coming to light in 1970. In the laboratories of University College London, John O’Keefe and his student Jonathan Dostrovsky recorded the electrical activity of neurons in the hippocampus of freely moving rats. They found a group of neurons that increased their activity only when a rat found itself in a particular location. They called them “place cells.”

Building on these early findings, O’Keefe and his colleague Lynn Nadel proposed that the hippocampus contains an invariant representation of space that does not depend on mood or desire. They called this representation the “cognitive map.” In their view, all of the brain’s place cells together represent the entirety of an animal’s environment, and whichever place cell is active indicates its current location. In other words, the hippocampus is like a GPS. It tells you where you are on a map and that map remains the same whether you are hungry and looking for food or sleepy and looking for a bed. O’Keefe and Nadel suggested that the absolute position represented in the hippocampal place cells provides a mental framework that can be used by an animal to find its way in any situation—be that to find food or a bed.

Over the next 40 years, other researchers—including the husband and wife duo of Edvard and May-Britt Moser—produced support for the idea that the brain’s hippocampal circuitry acts like an inner GPS. In recognition of their pioneering work, O’Keefe and the Mosers were awarded the 2014 Nobel Prize in physiology or medicine. You’d think that this would mean that the role of the hippocampus in guiding an animal through space was solved.

But studying the brain is never that straightforward. Like a match lighting a fuse, the 2014 Nobel Prize set off an explosion of experiments and ideas, some of which have pushed back against O’Keefe and Nadel’s early interpretation. This new work has suggested that when it comes to spatial navigation, the hippocampal circuit represents location information that is relative and malleable by experience rather than absolute. The study of the hippocampus seems to have stumbled into an age-old philosophical argument. [Continue reading…]

How to die with equanimity, without fear

 

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Plants, people, and decision-making


Laura Ruggles writes:

Plants are not simply organic, passive automata. We now know that they can sense and integrate information about dozens of different environmental variables, and that they use this knowledge to guide flexible, adaptive behaviour.

For example, plants can recognise whether nearby plants are kin or unrelated, and adjust their foraging strategies accordingly. The flower Impatiens pallida, also known as pale jewelweed, is one of several species that tends to devote a greater share of resources to growing leaves rather than roots when put with strangers – a tactic apparently geared towards competing for sunlight, an imperative that is diminished when you are growing next to your siblings. Plants also mount complex, targeted defences in response to recognising specific predators. The small, flowering Arabidopsis thaliana, also known as thale or mouse-ear cress, can detect the vibrations caused by caterpillars munching on it and so release oils and chemicals to repel the insects.

Plants also communicate with one another and other organisms, such as parasites and microbes, using a variety of channels – including ‘mycorrhizal networks’ of fungus that link up the root systems of multiple plants, like some kind of subterranean internet. Perhaps it’s not really so surprising, then, that plants learn and use memories for prediction and decision-making.

Can plants make decisions?

A lot of people will balk at such a notion for obvious reasons. For instance, the idea of plants as decision-makers suggests the possibility of some plants making good decisions, others bad, and some suffering from indecisiveness.

Isn’t what is being presented as a decision, simply the outcome of a particular constellation of factors that result in a particular outcome? In which case the outcome is determined and involves no decision.

Maybe, but let’s flip this around and instead of questioning a posited decision-making process inside plants, consider what happens inside humans.

My favorite way of doing this is by attempting to zero in on the moment an action is initiated — the moment, for instance, when one decides to stand up from sitting.

Within the general field of awareness, there will probably be a phase of rumination and some physical precursors of action, but the exact moment in which the action starts — that seems to come out of nowhere. We function more like puppets animated by an invisible puppeteer and then mask our lack of agency with a narrative of purpose, after the fact.

Not sure about the agentless nature of physical action? Then consider this: what’s the next thought that will pop into your head?

Of course, we never actually know what’s going to arrive before it gets delivered. The brain offers no tracking service like Amazon.