In preparing instructional materials, consideration must be given to the students' attention. Carl Hagfors has conducted a number of experiments measuring the electrodermal response simultaneously from a number of subjects viewing the same materials. When most subjects were attentive there was a large discursion of the recorder pen. When some were attentive and others not, the two effects cancel each other out. Such a technique might be easily adapted to aid in the preparation of instructional materials which gain the attention of nearly everyone. Furthermore, the addition of analog computer circuitry would make it possible to monitor the real-time attention of individual students in a class, and allow modification of presentation to recapture the attention of those students who are not being reached. (RH)