It is suggested that a reader's idea structure will affect processing of incoming information. Two aspects of the idea structure are further developed--the truth value aspect and the analytic level aspect. The idea structure can be characterized by ideas consisting of propositions which are considered to be more or less true or false (beliefs), or by ideas which consist of untested assertions. This is the truth value aspect. Further, the idea structure discriminates between different ideas, expressed as different tent to which tent to which the reader is capable of distinguishing between ideas. One empirical study investigates the relationship between 20 psychology student's beliefs before reading a text and their comprehension of it following two readings. A measurement of the readers belief structure in terms of truth values and analytic level showed that these accounted for 39% of the interindividual variation in comprehension after the first reading and 50% of the comprehension after the second reading. By adding a recall measurement, the variation accounted for in the first reading was increased to 56%. (Appendices discuss thinking, memory, and problem solving). (Author/RD)