What is PCT?
A hierarchy of control…
Earlier we noted that the closed loop is the only working ‘thing’ in PCT – it is the fundamental unit.
It is a bit like a house. Everything is made of bricks, and it is the arrangement of the bricks that makes it a house.
In PCT, closed loops make up the whole of the nervous system, but it is the way they are arranged that makes them work as they do - to manage very complex things.
In PCT the loops become organised in a hierarchy as the living thing develops.
At the lowest level, they control intensity of experience – like getting the just right amount of pressure to push a broken down car.
At the highest levels, the systems control experiences like a person’s idea of themselves, or their concept of loyalty.
When the loops are connected together, you can start to see how people can begin to control pretty complex things in their lives…
According to the theory, there are about eleven levels altogether, but the exact number isn’t that important… it’s how they connect together.
The concept of a hierarchy is found in many other psychological theories (e.g. see Stallings, 1974). However, PCT is exact about how the hierarchy is organised...
It’s all in the connections…
It’s really important to note how these many levels are connected.
Remember - the only loops that control behaviour are the ones right at the bottom – the ones that sit next to the environment.
All of the loops above that just set the standards, or reference values, for the loops below. And they send out these signals constantly, fanning out down the array of loops below. To some of these loops the signals are weighted so they are affected strongly. Others are affected very little, and there are a whole range of weights in between…
At the same time as all these signals are going down, a whole raft of signals are going up too… so the loops at the top get to manage the experiences coming in that have not been brought into line by the lower loops.
When the lower loops are controlling really well, we get the sense that things are going on automatically - we might not even notice that we are ‘in control’.
The levels of PCT are clearly explained in the book Make Sense of Behavior (Powers, 1998). For a more immediate explanation, see Bill Powers' online description at perceptualcontroltheory.org.
* Images reproduced with permission from 'People as Living Things' by Philip Runkel, www.livingcontrolsystems.com.