The differential effects of prior knowledge on learning: A study of two consecutive courses in earth sciences

We studied the occurrence and nature of learning in a university first year Introduction to Geomorphology course, and its relations with prior knowledge taught in a prerequisite course, and with the prior knowledge in the to be learned subjects. Ten dimensions of knowledge were tapped before and after the course by conventional and cognitive structure measures that were derived by the concept mapping methodology. The fine-grain analysis of learning outcomes yielded the following results: (a) students acquired only a small portion of the content in the course Introduction to Geomorphology, (b) the prior geological and geomorphological knowledge did not affect the learning of the new geomorphological contents, (c) the minor effects appeared within rather than across knowledge dimensions, and they affected mainly the learning of smaller knowledge units, and (d) concept definition cannot be considered a valid probe of knowledge. The differential effects of prior knowledge question the central, global and undifferentiated role that schema theories ascribe to prior knowledge in future learning. They call for greater reference to the exposed dimensions of knowledge by suggesting additional factors to be considered in the sequencing of courses, as well as to the acquisition of complex knowledge with partial meaning of the basic knowledge units, and the use of new cognitive structure probes of knowledge.