Fluid intelligence decline with age
- http://lesswrong.com/lw/4gi/age_fluid_intelligence_and_intelligent_posts/
- https://www.quora.com/Can-does-IQ-change-over-time
- http://joshuakhartshorne.org/papers/HartshorneGermine_inpress.pdf
http://www.amazon.com/Losing-It-Professor-laments-shrinking/dp/0300188234
http://content.time.com/time/health/article/0,8599,1909852,00.html
