the theory that encoding into memory and therefore subsequent retention depend on the depth of cognitive elaboration that the information receives and that deeper encoding improves memory. In early critical experiments, depth was achieved by processing the meaning of to-be-remembered words rather than focusing on shallower dimensions, such as the sound of the words. [formulated in 1972 by Canadian psychologist Fergus I. M. Craik (1935– ) and Robert S. Lockhart]