M. David Merrill reviewed instructional design theories to identify common principles. He devised the following five principles.

• Learning is promoted when learners are engaged in solving real-world problems.
• Learning is promoted when existing knowledge is activated as a foundation for new knowledge.
• earning is promoted when new knowledge is demonstrated to the learner.
• Learning is promoted when new knowledge is applied by the learner.
• Learning is promoted when new knowledge is integrated into the learner’s world.

First Principles of Instruction by M. David Merrill

The American Psychological Association has developed the Learner-centered Principles. The most important principle is to create a positive climate and positive relationships.