Note: As Mike Yassa, the lead author on the study, pointed out to me, the study did not actually test whether consuming caffeine before a task enhances memory, the problem being that other confounding factors can then lead to difference in performances on the test.
The US debt is more than $20.1 trillion, the largest in the world. Here are the 3 reasons it grew so large, and how it damages U.S. economic growth. The US debt is more than $20.1 trillion, the largest in the world.
Government Debt in Context. As of March 2012, the amount of government debt held by the public was $10.85 trillion, and the amount of intra-governmental debt was $4.74 trillion, for a total national debt of $15.6 trillion. And the U.S. national debt increases by roughly $4 billion every day.