That Neuroscience Guy - Why Do We "Pay" Attention?

Episode Date: March 15, 2021

We are often told we have to "pay" attention, but what does that really mean? In this episode, we discuss the neuroscience of Attention. 

Hi, my name is Olaf Krigolsen and I'm a neuroscientist at the University of Victoria. And in my spare time, I'm that neuroscience guy. Welcome to the podcast. We're told throughout our lives to pay attention, that it's really important to pay attention or we need to pay attention right now. But what does that really mean? On today's podcast, we're going to talk about the neuroscience of attention. Before we can talk about attention, we have to talk about a very simple model of how our brain works, and that's called the information processing model.

The information processing model of brain function stems from post-World War II, when people started to realize that the way our brain works might parallel that of a computer. And it's based on a very simple principle. You take in some input or information, you do some processing, and then there's some output. In terms of the human brain and the way this works with us,

the information processing model goes something like this. Our brain is constantly taking in sensory information, sight, sound, taste, smell, proprioception. But we don't need all of that information. Some of that information gets through, and we call that perception. You're aware of what someone is saying. That information is then processed and interpreted. Decisions are made, and we get a response. An easy way to think of attention is as a filter. It's a filter between sensory

information coming in and perception when we're aware of that information. Basically, if attention is not being paid, information doesn't get through from the sensory stage to the perceptual stage, and you're not aware of it. Think about when you're daydreaming. If you start daydreaming, people around you might be speaking and even speaking to you, but you lose that information because you're not paying attention. So sensory information is coming in, you can still hear the sounds, but there's no perception because attention is allocated elsewhere and that information is essentially filtered out. But what's happening in the brain? How does this work? There's a lot of research using monkeys that's shown that if a monkey is

paying attention to a specific location, if something appears there, neurons fire in the parietal cortex, and they fire more than if something appears in a location that the monkey isn't paying attention to. Let's recap that quickly. If something appears where the monkey is paying attention, there's neurons in a part of the brain called the parietal cortex that fire more. there's neurons in a part of the brain called the parietal cortex that fire more. Now, what does that mean? A simple way to think of that is that those neurons firing are amplifying the signal. In other words, they're making that signal larger, so the sensory information is amplified.

And because it's amplified, it stands out more than the other sensory information that's available to us at a given time. In these monkey studies, then, if the monkey moves their head and looks at a new location and something appears where they used to be paying attention, the firing in the parietal cortex is reduced. But if something appears in the new location where the monkey is looking, then you see increased firing again. So attention in this sense can be thought of as a spotlight. As we look around, at least in terms of visual attention, there's increased firing rates if something appears where we're looking, and that amplifies

the signal, facilitating perception. This is of course true for other senses, but we'll just stick with vision for now. Just so you know, in humans we see something similar if we look at brain waves. If we had a bunch of electrodes on your head and we were measuring brain waves, and we told you to look at a specific location, if something appeared there, we'd see an enhanced visual response in your brain waves than if something appeared where you weren't looking. And the spotlight model is true here as well. If we get you to look at a new location and something appears there, we see an enhancement of brainwaves. But if something appears where you're not looking, then we don't see that enhancement. There's another important

way we can think of attention, and we can think of it as a resource. And this is why talking on your cell phone while driving is so dangerous. To think of attention as a resource, you have to think of it as something of which you only have a finite supply. You can only allocate so much attention. What that means in terms of the brain is the parietal cortex can only do so much. Its amplification of information is limited. What that means in terms of the brain is the parietal cortex can only do so much. Its amplification of information is limited. So, if you're driving, it takes attention to drive.

You have to pay attention, no pun intended, to the vehicles around you, pedestrians, the car itself. And if you start talking on your cell phone, it takes attention for that. You have to listen to what the person is saying and have perception of those words. And this is where the resource model comes in. If you're paying too much attention to your talking, all of those neurons that are firing to amplify that information aren't available to amplify the information that's needed to drive. So your attention that you're spending on driving is reduced. And because that amplification isn't there, you tend to miss things. And this is why it's dangerous. You're driving along and you're having a conversation and you're amplifying the signal for that. The neurons in the parietal cortex aren't available to amplify the signal

for the visual information you need, say someone walking out on the road, and because of that you might miss it and we have an accident. The interesting point with this is it's not just talking on cell phones that would be dangerous while driving. It's just about anything. Eating, if you pay too much attention to eating while you drive, would be equally dangerous. Even talking to the person beside you, if you get too engrossed in the conversation and it uses too much of your attentional resource, then your ability to drive will be reduced. Now, I'm a bit hesitant to say the following, but funnily enough, this is something you can practice. Let me give you a different example. Imagine you're trying to dribble a basketball. If you're really good at basketball, you should be able to dribble a basketball with your head up

and looking around so that you can pay attention to the world around you. Because you don't want to be paying attention to dribbling, you want to be paying attention to the other players on your team and your opponents. But this isn't what it's like when we start. When you first learn to dribble a basketball, most of us put our head down and we're staring at the ball because we're trying to figure out what's going on. And we're spending our attentional resources there. All of our attention within the parietal cortex is focused on the ball. And if people are talking to us, our opponents are doing things, we miss all of it because we're focused on the ball. But what happens as we practice? As we get better at dribbling a basketball, it requires less attention.

The parietal cortex has to engage less, and thus we can use more attention on looking around and seeing what our opponents are doing and our teammates. In a driving context, I'm a bit scared to say this, but in principle, you could get better at talking on your cell phone while driving. If you practice this a lot and you became an expert driver, it would take less attention to drive. And in principle, talking on your cell phone wouldn't be so dangerous. The problem with this, of course, is that the world's unpredictable. You can never tell when someone's going to walk out on the street in front of you unexpectedly or a car changes lanes.

So please don't try that at home. We can also gain insight into attention from looking at stroke patients. A percentage of people that experience a stroke gain a condition called neglect. Neglect is interesting because it shows damage to our attentional systems. So if the stroke is in the parietal cortex or impacts the parietal cortex, you might see neglect. Nurses typically spot neglect first, and this is how they spot it. Imagine that someone that has neglect is sitting in their hospital bed and a plate of food is put in front of them. What the nurses see is that the patients only eat the food on the right side of the plate.

For some reason, the food on the left side of the plate is untouched. Another observation that they might make is that if a guest brings flowers and they're placed on the left-hand side of the room, the patient that has neglect might not notice that the flowers are there. And in some cases, if someone's standing on the left-hand side of the room, they don't see that person. This is what we call neglect. People with neglect are basically not paying attention to the left-hand side of the world. Now, why is this?

Well, in case you didn't know, the right-hand side of our brain processes information on the left-hand side of the world, and our left-hand side of the brain processes information on our right-hand side of the world. But why is there this left-side bias? As it turns out, the attentional systems that are in charge of filtering and resource allocation are on the right parietal cortex.

And if you have a stroke in this region, you experience neglect. So let's summarize. What is attention? Attention basically is a filter. Sensory information in the world needs to be filtered or amplified to make it through to perception or understanding. So if you're not paying attention, you lose that information. And attention can also be thought of as a resource. If it takes too much attention to do one thing, you'll have less attention to do something else, which is why talking on your cell phone is dangerous while you're driving. And we've discussed that attention seems to be, attention and our ability to deploy attention seems to be strongly associated with the parietal cortex and specifically the right parietal cortex.

My name is Olof Kregolsen and I'm that neuroscience guy. You can follow me on my website at www.olofkregolsen.com or on Twitter at that neuropsych guy. Thanks for listening and see you on the next podcast.