Knowledge, although seemingly available, is often not used for problem
solving. That means it remains ''inert.'' Three types of explanations
exist for this phenomenon. Metaprocess explanations assume that the r
elevant knowledge is available, but it is not used because of disturbe
d access processes (e.g., lacking metacognitive control). Structure de
ficit explanations suppose that the deficit is rooted in the structure
of the knowledge itself (i.e., the knowledge is not available in a fo
rm that allows for its application). In situatedness explanations, the
traditional concepts of knowledge and transfer are questioned. One ba
sic assumption of this perspective is that knowledge is fundamentally
situated (i.e., context-bound). In the last decade, instructional mode
ls have been developed that try to remedy the inert knowledge problem
and take into account important aspects that have been raised by the d
ifferent explanations.