Another cognitive capacity that shows more severe limitations in Alzheimer’s Disease (AD) is the ability to shift strategies. One task used extensively is the dimensional change card sort task (DCCS) originally designed by Zelazo (see link above) to test children. In the game, children must sort cards into two categories based on a single dimension — it could be that all the red ones go in one pile and all the blue ones go in a different pile. Later, that dimension, color, is supposed to be ignored in favor of a different dimension, shape. Now all the bunnies, both the red and the blue ones, go in one box and all the boats, regardless of their color, go in another box. Sorting in this way, typically 3-year old children can learn either sorting rule when presented first, but fail to switch to a second sorting rule (color to shape, or shape to color). By 5 years of age, most children can do this switching. This is considered a problem of executive function, or your ability to meta-think and select rules that guide your behavior within individual instances. Elderly people and AD patients show more rigidity in switching from one rule to another, and AD patients are typically appreciably worse at switching and show more errors and perseverate longer using older rules in tasks that demand switching (like in various Stroop tasks tested with AD patients).