The theory means that both systems are generally involved even in language
phenomena. The verbal system is a necessary player in all “language games” but it
is sufficient in only a few. In the most interesting and meaningful ones, the
verbal system draws on the rich knowledge base and gamesmanship of the
nonverbal system. Conversely, the nonverbal system cannot play language games
on its own, but it can play complex nonverbal “ solitaire.” The verbal system
dominates in some tasks (crosswords is a simple example) and the nonverbal
imagery system in others (e.g., jigsaw puzzles). Cognition is this variable pattern
of the interplay of the two systems according to the degree to which they have
developed.