The cognitive transformations triggered by tools
have two sides, paralleling the kinds of effects discussed above. One side
is learning effects with the tool. This recognizes the changed functioning
and expanded capability that takes place as the user uses and gets used
to particular tools. Impact occurs through the redistribution of a task‰s
cognitive load between persons and devices (e.g. Pea, 1993; Perkins, 1993),
including symbol-handling devices (e.g,. a spell checker) or across persons,
mediated by devices and symbol systems (telephones, fax machines). As these
examples suggest, such tools are all around us, but their possibility also
invites the design of special-purpose tools for supporting various cognitive
functions. For instance, experiments have shown that a computerized Reading
Partner that provides ongoing metacognitive-like guidance improves students‰
comprehension of texts while they read with the tool (Salomon, Globerson,
& Guterman, 1991).