"The consolidation factor, C, is a variable which is more or less intrinsic to the individual; ... Stated in simplest terms, C is the process of understanding what one has learned. It is 'getting the idea', 'catching on', having the 'Aha!' experience that may accompany or follow experiencing or learning something, and the relating of new learning to past learning and vice versa. When learning takes place without C acting upon it, it is less retrievable and much less transferable for use in solving problems that are more or less remote from the original learning situation. C is what is generally meant by the term intelligence, but it can be measured only through its interaction with experience or learning. There can be learning without experience (i.e., without C) but intelligence cannot be manifested without learning."

Arthur Jensen, Intelligence and educability