Cognitive load theory is an instructional theory based on our knowledge of human cognitive architecture. Current versions of the theory use evolutionary educational psychology to categorise the information that humans process and to provide a template for human cognitive architecture that is analogous to the information processes of evolutionary biology. That theoretical base can be used to generate instructional procedures. The theoretical base and its attendant instructional effects provide information on the characteristics and role of human problem solving in instructional design. It is concluded that teachable aspects of skilled problem solving are domain-specific rather than generic-cognitive in nature, and that those characteristics should determine what is taught and how it is taught.