These pieces of music adapt their rhythm and dynamic flow according to the driving style.

ENGADGET: Mini Cooper Connected app adjusts music based on driving style, stops when airbags deploy

But as Iraq has grown less hospitable to al-Qaeda-style jihadists, the human flow has reversed, with many heading back to Lebanon.

ECONOMIST: Syria and Lebanon

When the number of cars on the road is greater than that, the flow becomes unstable and natural fluctuations in our driving style alone are enough to cause traffic.

FORBES: How To Solve Traffic

Given that managers usually have a bias toward a particular style of investing, this causes even more money to flow to the most popular stocks.

ECONOMIST: Buttonwood