As people discover that they are no longer as good as they once were at certain tasks, they accommodate, shifting to activities that depend more on
a) emotional intelligence
b) accumulated knowledge
c) cognitive efficiency
d) perceptual speed

b) accumulated knowledge

Explanation:

This statement explains the fact that as people find out that they're not as good as they used to be at certain tasks, they stick with what they already know to do (the already accumulated knowledge), for fear of getting outside their comfort zone.

This concept is different from emotional intelligence (the intelligence one employs to read emotions and understand personalities), cognitive efficiency (using cognitive skills to solve problems) and perceptual speed (the capacity to perceive and understand situations and people).