On average, with each up-tick in BMI, a woman's cognitive test score decreased by nearly a full point as well-even after adjusting for vascular disease risks and other demographic factors.

However, copying collectors have the added cost of copying the data from one space to another, adjusting all references to point to the new copy.

But pessimists rightly point out that Americans face a harder job adjusting to higher energy prices than Europeans, given their dependence on cars and taste for suburban living.