The Sliver We See

The Salience Network and Ian McEwan's "Atonement"

“The choice we make of how we dispose our consciousness is the ultimate creative act: it renders the world what it is. It is, therefore, a moral act: it has consequences.”

—Iain McGilchrist, The Matter With Things

Image generated by Midjourney

A tightness has been building in my chest since I opened my eyes twenty minutes late this morning. I’m watching the clock on the car dashboard, the ETA for school drop-off creeping later and later. In the backseat, my children are oblivious and impossibly loud. I glance at my phone while my husband is talking to me—forty-nine unread emails and growing. We miss the green light. My pulse climbs.

Of course, these weren’t the only things happening around me. In every moment, far more is present than we could ever notice.¹ Reality offers itself in overwhelming detail. We can take in only a sliver. The sliver we select becomes the whole world we experience.

Neuroscientist Dr. Lucina Uddin has spent her career mapping this process. In her landmark 2014 paper in Nature Reviews Neuroscience, she describes a system called the salience network, the brain’s mechanism for deciding what matters.² Our brains are continuously toggling between inward focus and outward attention, between the storytelling mind that daydreams and the responsive mind that solves problems. The salience network acts as the switch operator between the two, constantly monitoring both internal and external signals to determine what matters most to this person, in this moment. Much of this happens below conscious awareness. We do not know we are selecting. We simply experience the world as it appears to us.

The consequences of where it directs us are often subtle. But sometimes they are profound, even devastating. Perhaps no story better illuminates the stakes of our attention than Ian McEwan’s Atonement. In this novel, a young girl named Briony witnesses something beyond her capacity to understand. What she notices, and how she interprets it, will have lifelong consequences for everyone involved.

Briony is what McEwan calls a child “possessed by a desire to have the world just so,” a girl who needs to tame the messiness of the world into something she can control. In fiction, she has discovered the ultimate satisfaction of this impulse. “A crisis in a heroine’s life could be made to coincide with hailstones, gales and thunder, whereas nuptials were generally blessed with good light and soft breezes.” But the weather is only the beginning. “A love of order also shaped the principles of justice, with death and marriage the main engines of housekeeping, the former being set aside exclusively for the morally dubious, the latter a reward withheld until the final page.” Her storytelling instinct is already, inseparably, a moral instinct. She watches the world looking for details that confirm the story writing itself in her mind.

But what the brain flags as important is never objective. It depends on personal history, emotional state, what we expect and what we fear. And for a child whose experiences are limited, whose framework for understanding the world has been built almost entirely from stories, the salience network reaches for what it knows.

It begins at a window. Watching from the nursery two stories up, Briony sees her older sister, Cecilia, and the family friend Robbie Turner at the garden fountain below. Robbie has “imperiously raised his hand…as though issuing a command which Cecilia dared not disobey.” Her sister seems “unable to resist him. At his insistence she was removing her clothes, and at such speed. She was out of her blouse, now she had let her skirt drop to the ground and was stepping out of it, while he looked on impatiently, hands on hips.” What could explain such submission? “What strange power did he have over her? Blackmail? Threats?” Then, as suddenly as it started, the scene ends. “From the deep shade of the fountain’s wall,” Cecilia picks up “a vase of flowers Briony had not noticed before…No words were exchanged with Robbie, not a glance in his direction. He was now staring into the water, and then he too was striding away, no doubt satisfied, round the side of the house.”

Later that evening, Briony stumbles upon Robbie and Cecilia in the family library. In the dim room, lit only by a desk lamp, she sees “dark shapes in the furthest corner. Though they were immobile, her immediate understanding was that she had interrupted an attack, a hand-to-hand fight.” As her eyes adjust, the details she registers build a case. “He had pushed his body against hers, pushing her dress right up above her knee and had trapped her where the shelves met at right angles. His left hand was behind her neck, gripping her hair, and with his right he held her forearm which was raised in protest, or self-defense.” He looks “so huge and wild.” Beside him, Cecilia’s “bare shoulders and thin arms so frail.” Briony’s earlier suspicions harden into certainty. “Something irreducibly human, or male, has threatened [...] her household.”

But then McEwan shows us the same moments through Cecilia’s eyes. At the fountain, Robbie is trying to help Cecilia fill a vase with water. Tangled in feelings for him she hasn’t yet named, she is determined to prove she does not need his help. When he reaches for the vase, “the effect on Cecilia was to cause her to tighten her grip.” They struggle, and a piece of porcelain breaks off and falls into the basin. Robbie’s raised hand, the gesture Briony read as an imperious command, is simply a warning: “he thought she was about to step backward onto the vase, and he raised his hand and pointed.” And when Cecilia strips and plunges into the freezing water, she is retrieving the pieces herself, on her own terms. The woman Briony sees as powerless is, in fact, the one wielding all the power.

And in the library, what Briony sees as “a hand-to-hand fight” is actually two people lost in a first embrace. Cecilia bites Robbie’s cheek, pulls his hair, pushes his face against her. These are the same physical details Briony registers as violence. From inside the moment, they are “nothing but obliterating sensation, thrilling and swelling.” Both sisters stand in the same room. But the details each notices, and the meaning each assigns, could not be more different.

When a young girl is assaulted on their property that night, Briony witnesses it from a distance, in the dark. She assumes it must be Robbie. By now the story has become so solid in her mind that there is no room for doubt. She tells the police she is certain. And with that certainty, she ruins his life.

It will take Briony a lifetime to see what she couldn’t that night. She believed she was looking through a clear window onto the truth. But it was really a lens, narrowing her vision to the details that fit everything she had ever read and written, everything she feared and did not yet understand. Her attention constructed a villain where there was only a man in love. And she acted accordingly.

If attention is a creative act, one that renders the world we inhabit, as McGilchrist writes, it is also a moral act. It has consequences. We are responsible for what we attend to, and how.

But if attention can build a darker world, it can also build a brighter one.

The next morning, we are running late again. But as we drive, I notice the bare branches of the winter trees sketching themselves against a white sky. In the backseat, my children are laughing at something I can’t quite hear. The sound fills the car like music. I look over at my husband’s profile as he drives, admiring the familiar line of it. I reach for his hand, and he smiles at me. I feel a warmth spreading through my chest.

The same morning. The same overwhelming world. A completely different sliver.

Thank you to my Write Hearted colleagues Kathy Ayers, Dana Allen, Linda Kaun, Rick Lewis and Brigitte Kratz for the feedback on this on!

1. Not all of the sensory information we fail to consciously process is lost. Neuroscientist Dr. Joel Pearson’s research suggests that much of it is stored below the threshold of awareness, where the brain continues to draw on it through rapid, nonconscious pattern recognition — what we experience as intuition. Intuition, in this framework, is not a mystical capacity but a cognitive one: the brain matching current input against a vast archive of prior experience to generate judgments faster than deliberate reasoning allows. Pearson’s work also explores what happens when this process misfires — when the patterns we’ve accumulated lead us to confident but incorrect conclusions, a phenomenon he calls “misintuition.” For more on intuition, see my essays: What the Body Knows and Grasping at Shadows.

2. Uddin describes three major networks that coordinate the brain’s response to an overwhelming world. The default mode network (DMN) activates during inward focus — daydreaming, self-reflection, memory, and imagination. The central executive network (CEN) engages when we attend to the external world — problem-solving, goal-directed behavior, and responding to things as they are. The salience network, with key nodes in the dorsal anterior insular cortex and the anterior cingulate cortex, operates as the switch between the two, mediating transitions between internal and external attention to guide appropriate responses to what it has flagged as significant. The right dorsal anterior insular cortex functions as what Uddin calls a “causal outflow hub,” generating control signals that directly influence both the DMN and CEN. Crucially, this process integrates not only external sensory information but internal bodily signals — heart rate, muscle tension, gut feeling — as the insula is the brain’s first cortical target of ascending interoceptive input. This means our physiological state actively shapes what we notice. What is perceived as salient, Uddin writes, “can be influenced by previous experiences and memories, current psychological state, goals and drives.” See Uddin, L. Q., “Salience processing and insular cortical function and dysfunction,” Nature Reviews Neuroscience, 2014.