Understanding why students are not naturally and easily able to generalize or apply what they have learned in other situations involves understanding what teachers want their students to learn; what learning is; what teaching is; and what is involved in generalizing or applying what has been learned. Research in educational psychology identifies three major types of knowledge: rote (i.e., memorization), declarative (i.e., knowledge of concepts) and procedural (i.e., knowledge of a physical or intellectual process, method, or skill). Knowledge does not automatically transfer between declarative and procedural knowledge. If teachers want their students to know about and be able to do things in different domains, both declarative and procedural knowledge will have to be taught in the same or each different domain. Learning results in the growth of new structures in the brain. New dendrites and synapses construct elaborate neural networks between neurons. Brain structures do not magically transfer information. Declarative knowledge is grown on different neural networks than procedural knowledge. The following learning principles can help teachers help students: (1) learning is physiological; (2) new brain structures grow with practice; (3) brain structures grow precisely and exclusively for what is practiced: (4) each person has their own unique pattern of brain structures; (5) students need to construct basic networks before they can construct more complex ones; (6) brain structures grow when learners are active; and (7) emotions affect the growth and function of brain structures. Teachers should help students make personal connections to new material and be allowed ample time to practice. (KP)