From publisher blurb:
When players level their characters, they make decisions regarding the new feats and skills they will select. These are conscious choices made by the players, usually to enhance their characters. Even unoptimal choices in a feat or skill are the players’ choice. Some players even select to advance in a different class. Often, the reasons behind these choices are hand waved as happening behind the scenes during the downtime between adventuring—the rogue somehow gains a level of wizard while the fighter learns the discipline to be a monk. It is easy to explain that the players were practicing all this time, and it gives players choices in making their characters. Aptitudes, on the other hand, are the GM’s decision to create and give out based on what players do in game.