of the type of heated debate that sometimes follows the implementation of constructivist-inspired curricula in schools. In the 1990s, mathematics textbooks based on new standards largely informed by constructivism were developed and promoted with government support. Although constructivist theory does not require eliminating instruction entirely, some textbooks seemed to recommend this extreme. Some parents and mathematicians protested the design of textbooks that omitted or de-emphasized instruction of standard mathematical methods. Supporters responded that the methods were to be eventually discovered under direction by the teacher, but since this was missing or unclear, many insisted the textbooks were designed to deliberately eliminate instruction of standard methods. In one commonly adopted text, the standard formula for the area of a circle is to be derived in the classroom, but not actually printed in the student textbook as is explained by the developers of CMP: "The student role of formulating, representing, clarifying, communicating, and reflecting on ideas leads to an increase in learning. If the format of the texts included many worked examples, the student role would then become merely reproducing these examples with small modifications." Similarly, this approach has been applied to reading with whole language and inquiry-based science that emphasizes the importance of devising rather than just performing hands-on experiments as early as the elementary grades (traditionally done by research scientists), rather than studying facts. In other areas of curriculum such as social studies and writing are relying more on "higher order thinking skills" rather than memorization of dates, grammar or spelling rules or reciting correct answers. Advocates of this approach counter that the constructivism does not require going to extremes, that in fact teachable moments should regularly infuse the experience with the more traditional teaching. The primary differentiation from the traditional approach being that the engagement of the students in their learning makes them more receptive to learning things at an appropriate time, rather than on a preset schedule. Importance of structure in constructivist learning environments During the 1990s, several theorists began to study the cognitive load of novices (those with little or no prior knowledge of the subject matter) during problem solving. Cognitive load theory was applied in several contexts. Based on the results of their research, these authors do not support the idea of allowing novices to interact with ill-structured learning environments. Ill-structured learning environments rely on the learner to discover problem solutions. Jonassen (1997) also suggested that