She gave schoolchildren an 850-word passage about the biology of influenza, broken down into seven paragraphs. This was an unfamiliar topic to them, and they knew they were going to be tested on the content afterwards.
Half the pupils were asked to produce a drawing to accompany each of the paragraphs of the text; the other half only had the text itself to study.
In a multiple choice test afterwards the children who used drawings to aid their learning scored an average of 61%. The pupils who only studied the text scored an average of just 44%.
In further tests, pupils were given pictures to accompany the text. But even then, they still didn't score as highly as the schoolchildren who drew their own pictures.
They also found that the children who took most care over their drawings, also got the best scores.
Colours help create further delineation on your map and are another tool to help embed the information in your memory. By associating something with a colour as well the title of the group it's in, you are remembering it twice. You are using two different parts of the brain, the one that deals with colour association and the one that deals with language.