In a homeostatic system, the system has no choice but to compare the sensory information the system is receiving with its target value. That means the system has to compare all sensory information to the target value (“is it good?”). The system needs the sensory information to tell it what is good and what is not good. The target value is the value the system should strive to achieve.
The goal of homeostatic systems is to get the sensory information to tell the brain what it should be doing. The sensory information is often described as “noisy” and the target value is often described as “quiet.” If the sensory information is noisy, then the target value is quiet. If the sensory information is quiet, then the target value is loud.
The first thing to realize about homeostasis is that it is an unstable state, a state of being. A homeostatic system is a system that tries to get the sensory information to tell the brain what it should be doing. To achieve this, a homeostatic system needs the sensory information to tell the brain what is good and what is bad. This means that homeostatic systems tend to be a bit unstable.
Homeostatic systems can sometimes be quite unstable, especially when they are working in the context of an environment that is not pleasant. For example, if you are in a room you don’t like the sound of then might be the case that the sensory information tells the brain to be quiet and the target value is loud. In that case, you might want to avoid the sensory information.
So if the sensory information tells you to be quiet, you could instead choose to use the target value to try and get rid of that.
A homeostatic system is a system where the sensory information tells you a target value, so you can use it to try and overcome that sensory information. For example, in your house, the sensory information might tell you that you should be on the couch, and the target value might be that you should be in bed. In that situation, you might want to try and use the target value to get rid of the sensory information, so that you can have a more pleasant experience.
Sounds like a good way of building a homeostatic system. But actually there’s an interesting problem with this. A homeostatic system is only as good as its target value. If the sensory information is telling you that you should be sitting on the couch and the target value is that you should be laying in bed, you’re not going to have a great homeostatic system. You might have a good system, but it’s very far from good.
And the reason is that when we hear or see something which we think is pleasant but isn’t, we’re not really aware of it. We are so accustomed to the sensory information that we ignore the target value and use the sensory information to determine our comfort.
We are actually pretty good at this, but we can’t always remember to use the target value to actually determine our comfort. In fact it’s a pretty bad habit, and one that we all have.
Like all systems, the brain needs to be fed by sensory data. We need to hear or see something that we think is pleasant, but are not really aware of it. This is called sensory overload which is why we get tired and anxious when we hear or see something we think is unpleasant, but aren’t really aware of. So we try to make our own sensory systems as efficient as possible and then the sensory overload is the result.