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.
Weighing in at 17.5 trillion dollars, the U.S. national debt is a colossal behemoth. And almost all of that debt has been accumulated over the past 40 years. In fact, 40 years ago the U.S. national debt was less than half a trillion dollars.