How Much Can Your Mind Keep Track Of?

Cooking shows on TV usually give a Web address where you can find, read, and print out the recipe of the dish created on that day’s show. The reason is obvious: It’s too hard to just follow along with what the chef is doing, let alone remember it all. There are too many directions and ingredients — too many variables and steps in the process to keep track of quickly.

New research shows why it doesn’t take much for a new problem or an unfamiliar task to tax our thinking. According to University of Queensland cognitive science researchers Graeme S. Halford, Rosemary Baker, Julie E. McCredden and John D. Bain of Griffith University, the number of individual variables we can mentally handle while trying to solve a problem (like baking a lemon meringue pie) is relatively small: Four variables are difficult; five are nearly impossible.