Information processing theory informs us the way people learn knowledge. The way of gathering information and data and facts. Then the way of organizing that data in mind in terms of schema (structure and relations and connections). This tells us how people learn and remember things in memory. Then the information processing theory model also tells us the way information retrieval is done while recalling facts from memory.
So the main use of knowing this theory and model, is that we can design the teaching methods, tools, text, lessons, and most importantly the examinations. How these can be presented to the students so that information remembering or retention is maximized in the minds of the students.
As education means teaching, learning and evaluating the learning of the students. In all these aspects, the information theory models have direct applications. Nowadays the questionnaires, question papers are designed for maximizing learning.