The Interacting Cognitive Subsystems framework, ICS (Barnard, 1985) propose
s that central executive phenomena can be accounted for by two autonomous s
ubsystems, which process different forms of meaning: propositional and sche
matic (implicational) meanings. The apparent supervisory role of the execut
ive arises from limitations on the exchange of information between these an
d other cognitive subsystems. This general proposal is elaborated in four e
xperiments in which a total of 1,293 participants are asked to spontaneousl
y generate a large verbal number to varying task constraints, with the inte
ntion of specifying the representations of number and task that underlie re
sponses. Responses change systematically according to participants' use of
explicit propositional information provided by the instructions, and inferr
ed implicational information about what the experimenter is requesting. The
re was a high error rate (between 6% and 24%), participants producing respo
nses that did not fall within the large range indicated by the instructions
. The studies support the distinction between propositional and implication
al processing in executive function, and provide a framework for understand
ing normal executive representations and processes.