Visual cortex is that part of the brain in which visual stimuli are interpreted. It has been very well developed in the course of evolution and that is why we say one picture is worth a thousand words. Indeed if you look at the number of details kept in a picture and the easiness with which your memory can retain them, you will notice that our verbal processing power is greatly inferior as compared with the visual processing power. The same refers to memory. A graphic representation of information is usually far less volatile.

Usually it takes much less time to formulate a simple question-and-answer pair than to find or produce a neat graphic image. This is why you will probably always have to weigh up cost and profits in using graphics in your learning material. Well-employed images will greatly reduce your learning time in areas such as anatomy, geography, geometry, chemistry, history, and many more.

The power of imagery explains why the concept of Tony Buzan's mind maps is so popular. A mind map is an abstract picture in which connections between its components reflect the logical connections between individual concepts.