Possible mechanisms by which this might occur include the following: (a) Knowledge can enhance memory in the form of richer and more elaborate encoding and more effective retrieval cues facilitated by a superior organizational structuring of information; (b) knowledge can result in easier access to relevant information and better organized representations of the problem, resulting in enhanced problem-solving skills; (c) knowledge of past consequences of various alternatives can provide an effortless means of making accurate predictions regarding future consequences; (d) knowledge can enable reliance on previously compiled efficient algorithms, rather than on slow and controlled processes; and (e) knowledge of prior solutions to familiar problems can reduce online processing requirements. Commonly used indirect measures of cognitive reserve include number of years of education, literacy level, vocabulary knowledge, occupational complexity, estimated premorbid intelligence, and frequency and range of participation in mentally stimulating leisure activities (e.g., reading, writing, doing crossword puzzles, playing board or card games, playing music) or complex mental activities generally.

It is important to distinguish cognitive reserve from the closely related brain reserve, which posits that brain-based anatomical differences among people convey differential abilities to tolerate neuronal damage or loss before developing cognitive impairment. Despite the different emphases of the two terms, many researchers use them interchangeably.