In this sense, it is the opposite of the more usual scenario of inflation, whose effect is to tax currency holders and lenders (savers) and use the proceeds to subsidize borrowers, including governments, and to cause malinvestment as overinvestment. Thus inflation encourages short term consumption and can similarly over-stimulate investment in projects that may not be worthwhile in real terms (for example the housing or Dot-com bubbles), while deflation retards investment even when there is a real-world demand not being met. In modern economies, deflation is usually caused by a drop in aggregate demand, and is associated with economic depression, as occurred in the Great Depression and the Long Depression.