Appreciable variations in price level are soon noticed by individuals, in a variety of ways, especially by those whose incomes are constant. A rise in prices has exactly the same effect as a decrease in income, and conversely a fall of the price level is actually an increase of the income. There is, to be sure, in most cases a tendency for the income to follow price level; yet salaries and wages almost always lag behind a rise in prices, while they respond more quickly to a fall. Price fluctuations are largely responsible for social unrest. When one has adjusted his income to his expenditures, any change, especially an upward tendency in prices, is not welcome. The most striking effect is felt by those who depend entirely on funded incomes. Thus, a widow receiving a life insurance annuity of $600 a year is bound to feel the pinch of an increase in the price level. She finds it necessary to curtail portions of her accustomed expenditures. Her command over goods in 1918, for example, was scarcely more than half as great as it had been twenty years before. In reality, then, her income had shrunk from $600 to $300.