Are US Consumers Irrational?

From the NYTIMES:

http://www.nytimes.com/2015/10/20/upshot/when-gas-becomes-cheaper-americans-buy-more-expensive-gas.html

“When gas prices fall, Americans reliably do two things that don’t make much sense. They spend more of the windfall on gasoline than they would if the money came from somewhere else. And they don’t just buy more gasoline. They switch from regular gas to high-octane.”