The correct term to fill in the blank would be "crystallized intelligence (Gc)". Physicians, teachers, musicians, and politicians continue to work well into old age largely due to crystallized intelligence, which tends to increase over time. It is the ability to utilize experience, knowledge and skills. It is not a memory but it does uses on the access of the long term memory. This type of intelligence is an individual's lifetime achievement intellectually. It is said to increase with time or age since the experiences that one undergoes would expand his knowledge. The other type of intelligence is called the fluid intelligence.