The thing about the amygdala is that it is able to process the relevant information extremely fast, especially when compared to other parts of the brain. I mentioned that the amygdala is involved in decision-making, and is an unconscious area of the brain. We also have a conscious part of our brain that we often use to make decisions; in fact you are using it right now to read this sentence. The prefrontal cortex, the part of our brain that sits just behind the forehead, is where most of the activity we refer to as “thinking” occurs. Using this part of our brain to make decisions is completely appropriate most of the time, but it is slow. Our conscious thought process considers the pros and cons of each choice, considers past experiences and imagines future outcomes, factors in social norms and expectations, and does a whole bunch of other stuff I am leaving out because this paragraph is already going to be too long, but you get the idea. Conscious decision-making is slow, very slow. Imagine if we engaged that process to decide if we are being threatened. Is that a bear? I wonder what kind of bear it is. I know that bears can be dangerous, but so can dogs and my brother’s dog is really nice. It looks like it could attack, but also maybe it is just curious . . . and suddenly I am being mauled. We are talking about identifying potential danger here, so the faster we can come to the right conclusion, the more likely we’ll survive.
When the amygdala determines that the stimulus represents a potential threat, it sends a signal to an area called the hypothalamus, another part of the limbic system. The hypothalamus in turn activates the sympathetic nervous system, which is responsible for a whole host of physiological changes. These changes, which I will discuss in a later section, all get our body ready for whatever action we will need to take. This entire system works so fast that our body will experience these changes before our conscious mind has caught up. In other words, we will encounter a stimulus, unconsciously decide that it is threatening, and start reacting to it before we are aware of what we’ve encountered.16 This is a great thing when we are actually being threatened. For example, before you realize there is a bear, you are likely already reacting to it. However, if the situation does not warrant a stress response, it can cause us to act before we get a chance to think. You could be driving as the traffic suddenly picks up. Before you become aware of it, you are already agitated and that agitation is probably going to influence your behavior.
Speaking of behavior, our amygdala also sends its information to an area called the nucleus accumbens, located fairly close to the center of the brain. I like to point out its location because if you knew nothing else about it you would probably guess that it’s pretty important. With the exception of, say, the Star Destroyer ships from Star Wars, generally the more important something is, the more protected it is. Unlike the high-ranking officers of the Empire (whose bridge is located in the most vulnerable part of the ship), not only is the nucleus accumbens protected by the skull but it is also insulated by layers of brain tissue. All the structures packed into the core of the brain are crucial to supporting life. You can live without your ability to think, and a few examples of people that seem to prove this come to mind, but you’d have a hard time living without these areas.
The nucleus accumbens does not produce our behavior, but it is important for motivating it. You may have previously learned that it is involved in our experience of reward, or learning through reinforcement. Those things are true, but to put it simply (my favorite way to put it), the accumbens assesses the relative value of our options. The value of any given option can be positive, as in it is going to improve our life by adding something, commonly pleasurable, to it (we call this “positive reinforcement” or “reward”), or negative, as in it is going to improve our life by removing something uncomfortable or painful (called “negative reinforcement” or “relief”). Basically, I can improve my life by eating chocolate cake or by escaping a threat. The thing about the accumbens is that it doesn’t care if life improvement comes from reward or relief, it is the relative value that matters. If eating cake brings me more immediate value than doing twenty pushups, you can guess which option my brain will pick. I’ll have more to say on this later.
Hypothetically, let’s say we are facing some sort of threatening situation. Hmmm, I don’t know . . . let’s say we are being attacked by a bear. Yeah, that’s it! Our amygdala has just determined that this situation represents danger and has alerted our sympathetic nervous system. At the same time, it signals our accumbens, which kind of asks itself, “What should I do?” Perhaps it identifies a couple options. Maybe one option is that we can prepare to defend ourselves. Or maybe running is an option, or maybe we can lie down, play dead, and hope the bear is gentle. All of these options involve relief as opposed to reward. I know, it’s hard to believe, but there are some problems chocolate cake cannot solve.
Running, preparing for a fight, and playing dead are not very complex behaviors, and that is why they’re immediately considered. The nucleus accumbens identifies options that we have practiced so well throughout our lifetime (you know, during all those times you ran, fought, or played dead) that our brain has learned to perform these tasks without thinking about it. Remember that conscious thought in this context would slow us down, so the options are simple well-learned behaviors. You may recognize these three options as fight, flight, or freeze, respectively. Each of these options has a value associated with it based on past experiences, and the option with the greatest relative value is the one your nucleus accumbens is going to pick. Are you a really good fighter? Then pick up a rock or a stick and prepare for battle! Are you a really good runner? Then get those legs moving! Are you like me and really good at neither of those things? I can’t even remember the last fight I was in and the last time I ran, I am pretty sure it was to catch an ice cream truck. Better assume the fetal position and hope that you don’t taste good. Some of us will even make ourselves not taste good, if you know what I mean, and spoil the meal.17
By now you must understand my use of simplified hypothetical examples. But just in case: do not take me literally. I am many things, but an expert on bears is not one of them. Before you go boxing ursine beasts or trying to outrun an animal that can reach 40 mph,18 do a little research. There are resources out there about what to do when you encounter a bear, so don’t blame me if you get eaten, Goldilocks.
Let me use another example. Imagine you are driving down the highway and suddenly find yourself in a traffic jam. As soon as your brain picks up on the impending slowdown, your amygdala identifies it as a threat and sends word to your nucleus accumbens. Your accumbens in turn evaluates your options. You can either fight, flee, or freeze. Obviously, these are generic categories of behavior, but how would those options be translated into the traffic situation? Fighting in traffic could mean a number of different behaviors like honking the horn excessively, yelling at other drivers, flipping the bird or flicking them off or whatever you call it locally (pointing at Canada?), or driving aggressively. On the other hand, it is hard to flee from traffic, but maybe you could take the next available exit or even move over to the shoulder. Let’s say that for whatever reason, fighting looks like a more valuable response to your brain than fleeing, and so you start laying into your horn, annoying the inconsiderate drivers who dared to be stuck in traffic before you. I would like to remind you that all of this, from identifying the “threat” of traffic to obnoxiously honking your horn and raising your middle finger, happened without any conscious thought.
At least I like to believe that this behavior is unconsciously motivated; I would have a really low opinion of our species if I didn’t. I can’t imagine a rational thought process that would lead someone to think this behavior is a potentially useful strategy to cope with traffic. Like we are all going to hear the honking horn and suddenly think, Hey, I better let this guy through. It sounds like he may be slightly late for work! It’s a fight response, and given the context it may seem perfectly natural to the unconscious brain.
Finally, there is the prefrontal cortex. Not that this completes the entire discussion on brain