In neo-Piagetian skill theory (Granott, Fischer), a cognitive structure used in the process of bridging. A shell consists of a higher-order psychological structure whose specific content is only partially constructed. During the process of bridging, shells function as self-scaffolding structures that support an individual‚was attempt to order knowledge construction in the direction specified by the shell
. See Bridging, neo-Piagetian theories of cognitive development