The overall principal is simple. The more dollars you add to a system with a fixed amount of goods the less each dollar is worth. The government prints those dollars and adds them to the system. Inflation.
Or the more you vary supply with fixed amount of dollars. Or even just psychological sentiment to want to spend. That's the expectations factor mentioned.
If people believe higher inflation is coming they will tend to want to spend now before the prices increase. If you are needing a house and you expect the house prices to continue inflating, then the pressure is to hurry up and buy before it gets more expensive. It becomes ironically self-re-enforcing.
Same with deflaltion. If you expect housing t drop in price the incentive is to wait as long as possible because it is always getting cheaper. Which means house have to get cheap to move. Self-fulfilling.
The self-re-enforcing nature is why they are called spirals. Once they get momentum it is the Devil to stop.
I believe we will soon get a object lesson in this behavior.
I'm just not sure which way it is going to go.
