Bonds and Interest Rates and Consumers, oh my!

Supply and demand are the cause for ups and downs in the stock market. And individual consumers create supply and demand. So what affects an individual's ability to purchase or creates an impetus to sell?

The bond market has a great influence on the stock market and the economy. The bond market determines interest rates. Bond prices and interest rates have an inverse relationship. As bond prices go up, interest rates go down. As bond prices go down, interest rates go up.

The rise and fall of interest rates directly affect the economy because businesses have to borrow money, consumers have to borrow money, and consumers and businesses have mortgages on property. The higher the interest rates, the more it costs to maintain the debt, and the less money there is to invest.

So, the question arises: What determines interest rates in the bond market?