Recall that the investment function is downward sloping with respect to the interest rate. When interest rates are high, planned real investment is low (because with high rates, fewer investment opportunities have rates of return that are higher than the cost of the investment, the interest rate).

Suppose a growing economy has consistently had large increases (rightward shifts) in its investment function for the last 10 years. This year, however, the increase in the investment function is less than half of the increase of the previous period. What might be possible causes of the diminishment of the rightward shifts of this nation’s investment function?