How Does The Brain Pay Attention?

There is no single attention center. Attention runs on the frontoparietal network linking the prefrontal and parietal cortex, split into a dorsal system for deliberate top-down focus and a ventral system that reacts to surprises. The brain can’t truly multitask, so it focuses on a few things and tunes out the rest.

“Are you deaf? I’ve been calling you for the last 5 minutes!”

Engrossed in the TV or on our smartphones, you don’t hear someone addressing you. You plead your case saying “Sorry, I didn’t hear you!” But obviously, you’re not believed. And yet that momentary deafness is real. You really didn’t hear anything. When your brain focuses hard on one thing, it goes a little deaf, and in some cases a little blind, to everything else.

These instances raise an interesting implication: the brain must selectively pay attention to some things while ignoring others. If so, how does it do that?

What Is Attention?

“Everyone knows what attention is. It is the taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought. … It implies withdrawal from some things in order to deal effectively with others…” Notes William James in 1890 in one of the earliest discussions about attention (The Principles of Psychology, pp. 403–404).

You’ve been paying attention to things all your life. You’re doing it now as your eyes and brain attend to decoding the weird symbols on the screen. But, just to show you how your attention works, let’s do a little test. Watch the following video and pay close attention to the instructions that appear on the screen.

If you’re reading this, you’ve either taken the test (great!) or skipped ahead (boo!).

If you did watch the video, did you notice the gorilla amble across the screen? No? Try again and see if you can spot it.

This experiment was performed by researchers Christopher Chabris and Daniel Simons and published in 1999. They showed observers the gorilla video and noted how many of them noticed the gorilla. Almost half didn’t (around 46% across all conditions missed it entirely).

I showed the video to the people at the office and many didn’t spot the gorilla. When I pointed it out to them, they reacted with disbelief, surprise and alarm. “I was staring right at the screen. I swear it wasn’t there!” they say.

This research won the Ig Nobel Prize, a prize given to improbable and slightly wacky scientific inquiry. Besides being entertaining and going viral on the internet, it lays bare just how flawed our brains can be. It confronts us with what psychologists call inattentional blindness.

Inattentional Blindness And Cocktail Party Effect

Inattentional blindness isn’t literal blindness. It is the failure to notice something unexpected, like a gorilla in a basketball match, when one is focusing on something else, like the number of passes. Your brain ignores all other information that isn’t necessary to the task you are concentrating on. While you were watching the video, the passes were of utmost importance. The gorilla’s presence wouldn’t help you with counting the number of passes.

And this is how the brain pays attention in real life as well.

For a more relatable example consider the following scenario. You’re at a party. There is free food, flowing drink, groovy music and a whole lot of talk. You’ve met a school friend after ages and begin to catch up on missed moments. The two of you reminisce about that math teacher with the weird accent. You’ll notice (or won’t) that you don’t have any trouble holding a conversation with your friend. All the background chatter and the groovy music never bothers your conversation, almost like you are deaf to it.

This is what fun people call the ‘cocktail party effect’ or what the serious ones call selective hearing or inattentional deafness.

William James’s definition of attention probably makes a lot more sense now.

Parts Of The Brain Involved In Paying Attention

Take a moment to look around you right now. There are a hundred different things that you could focus on. All the visual stimulus (should you read the words, look at the font or all the recommended articles on the right-hand side?) around you, the cacophony of sounds, the smells (or lack of them), and how the body is positioned.

It is impossible for your brain to process all this information at once. Instead, it takes the easy way out, focusing on a few things and tuning out everything else.

There is no single attention center in the brain doing all this. Unlike fear, which neuroscientists have largely tied to the amygdala, attention draws on different areas spread across the brain. These networks pull in multiple sensory systems along with the higher cognitive regions that decide what is worth focusing on. Discussing them all would be like writing a neuroanatomy textbook. So, for the sake of brevity and not losing your attention, I’ll discuss the main players broadly.

Frontoparietal Attention Network And Frontal Eye Fields

The main attention machinery in the brain is the frontoparietal attention network, a web of connections between parts of the frontal lobe and the parietal lobe. Neuroscientists Maurizio Corbetta and Gordon Shulman split it into two cooperating systems, and the distinction is worth knowing because it maps neatly onto the two ways we pay attention.

The first is the dorsal attention network, which handles top-down attention: the deliberate, goal-directed kind you use when you decide to count basketball passes or hunt for your keys. It runs from the frontal eye fields down to the intraparietal sulcus, and it is steered largely by the prefrontal cortex, the brain’s executive command center. When you choose what to focus on, it is the prefrontal cortex that sends the “pay attention to this” signal that biases the rest of the brain in favor of whatever you have picked.

The second is the ventral attention network, which handles bottom-up attention: the involuntary kind that gets hijacked when something unexpected happens. Largely lateralized to the right side of the brain, it acts as a sort of circuit breaker. When a fire alarm blares or a gorilla wanders into a basketball game, this network yanks your focus away from whatever you were doing and points it at the surprise. The two systems are in constant negotiation, which is exactly why a strong enough distraction can override even hard concentration.

One notable region inside the dorsal network is the Frontal Eye Fields (FEF). As the name suggests, it helps aim our eyes at things, but it does much more than steer eyeballs. The FEF can shift attention to a spot without your eyes moving at all, something psychologists call covert attention. It is how you can stare straight ahead while secretly keeping tabs on someone in your peripheral vision, or eavesdrop on the juicy gossip at the next table without ever turning your head.

Then there is the thalamus, a structure buried deep near the center of the brain that sifts through the flood of sensory inputs arriving every moment. The thalamus is often called the brain’s “relay station,” because it relays information to and from higher regions like the prefrontal cortex. Think of it as a post office sorting an enormous pile of mail, deciding what gets delivered upstairs and what gets binned. Parts of it, such as the pulvinar and the thalamic reticular nucleus, actively amplify the signals you are attending to while turning down the ones you are not, doing some of the heavy lifting our attention depends on.

None of these regions works alone, and the brain also leans on chemical messengers to set the right state. The neurotransmitter norepinephrine, released from a small brainstem hub called the locus coeruleus, governs alertness, the readiness to react when you sense something is about to happen. Acetylcholine, meanwhile, helps with orienting, the act of shifting your focus to a particular place. So while the wiring decides where attention goes, these neuromodulators help decide how sharply it is tuned.

The structures listed here, and plenty more that aren’t, work together to sort what gets attended to from what doesn’t. Inattentional blindness and deafness are the visible result of all that prioritizing.

Why Does This Matter?

Does it matter to know about how we pay attention?

Absolutely.

It matters because besides annoying your mother or not noticing a silly gorilla sashaying in a psych test, how we pay attention can reveal how our attention is fallible.

Take driving for example. A distraction while driving could lead to a moment of blindness and the difference between life and death.

Or consider those working in high-pressure environments, like a medical practitioner administering a drug to a patient. A slight diversion in attention, and instead of the right dose, the patient might receive an overdose or the wrong drug entirely.

These are real-life scenarios that could happen and little slips like this could be life-threatening.

Studying the brain, how it processes information, and how it attends to that information allows us to create methods to prevent such accidents and other casualties from happening. Examples abound where an understanding of how quickly the brain can switch attention from one task to another, such as in air traffic control, could prevent mistakes.

It also has implications for neurological disorders such as ADHD and those caused by accidents.

Paying attention requires effort, and the brain has a hard limit on how much it can juggle at once. There is a genuine bottleneck in the system, which is why true multitasking is mostly a myth. What feels like doing two things at once is really your brain switching rapidly between them, paying a small toll in time and accuracy with every switch. So our imperfect brains settled on a compromise: focus on a few things and quietly neglect any information they don’t think they need for the task at hand.

The next time you’re reading or watching TV and don’t hear your mother yelling out your name, just tell her it wasn’t your fault.