a type of general intelligence (g)
= experience, using heuristics (shortcuts)
* is use it or lose it (the more you use your brain, the more active it is)
* synaptic genesis = brain grows new neurons
* is learning-based intelligence (makes sense, because the older you get, the more life experience and time you have to develop heuristics in life)
* This combats the myth of ageism; although elders get older, they also get smarter!