ABSTRACT
Illustrations that instruct foster acquisition of knowledge in the learner and are of particular value in helping a learner to build a mental model of how something works. Decorative illustrations fill space on the page, but do not enhance the message of the text. Hence, they do not affect the reader’s cognitive processing of the text. Cognitive components theory is based on cognitive task analysis in which the to-be-learned material is broken down into specific knowledge that the learner acquires. Representational illustrations portray a single element and serve to direct the reader’s attention. Explanative illustrations explain how some system or process works by showing the principle-based relations among state changes in the major elements in the system. Organizational illustrations depict the structural relations among two or more elements. They help to guide the reader’s attention to certain specific elements and help him or her to build internal connections among the elements.
