<p>Human cognitive architecture is concerned with how we learn, think and solve problems. It consists of a series of integrated components that closely influence each other. Those components include a biologically primary system that consists of largely general knowledge and skills that we have evolved to automatically acquire and a biologically secondary system that requires conscious effort to acquire unfamiliar, domain-specific information either by problem-solving or from other people. As determined by element interactivity, the complexity of secondary knowledge depends on its intrinsic nature and whether it is acquired by problem solving or by transmission from other people. Unfamiliar, secondary information is processed in a working memory that is limited in capacity and duration before being stored in a long-term memory with unknown capacity and duration limits. Indefinite amounts of familiar information stored in long-term memory can be returned to working memory to govern action appropriate to the extant environment. Cognitive load theory uses this architecture to generate instructional hypotheses that are tested using randomised, controlled trials with successful, replicated tests leading to cognitive load theory effects that serve to both validate the theory and provide instructional and general communication procedures.</p>