Thomas, J. L. (1976). The use of pictorial illustrations in instruction: Current findings and implications for further research. ED 160 108.

Any individual upon examining textbooks being used for instruction is struck by the plethora of pictorial illustrations adjunct to written material. Research literature indicates that the haphazard selection technique for the inclusion of pictures in textbooks heavily outweighs the empirical investigations. Current investigations have explored a variety of factors influencing the use of illustrations, such as color, time, age, achievement, and sex of the reader. Researchers are calling for planned research designs which will alow for the possibility of aptitude treatment interaction. Two areas receiving concentrated research are reading and science. Findings to date indicate a number of other areas which need further research.