Fluid Intelligence

There are two main type of intelligence, crystallized intelligence and fluid intelligence. Fluid intelligence is your ability to reason in an abstract way. For example, if I asked you to come up with as many different possible uses for a tire, you would have to use very abstract reasoning -- think about what a tire is, the different types, the sizes, etc., then go through cognitive lists of situations, uses, and much more. One unfortunate problem with this type of reasoning is that it tends to decrease during later adulthood.