This book proposes a combination of cognitive modeling with model-based user interface
development to tackle the problem of maintaining the usability of applications that target
several device types at once (e.g. desktop PC smart phone smart TV). Model-based
applications provide interesting meta-information about the elements of the user interface (UI)
that are accessible through computational introspection. Cognitive user models can capitalize
on this meta-information to provide improved predictions of the interaction behavior of future
human users of applications under development. In order to achieve this cognitive processes
that link UI properties to usability aspects like effectiveness (user error) and efficiency
(task completion time) are established empirically are explained through cognitive modeling
and are validated in the course of this treatise. In the case of user error the book develops
an extended model of sequential action control based on the Memory for Goals theory and it is
confirmed in different behavioral domains and experimental paradigms.This new model of user
cognition and behavior is implemented using the MeMo workbench and integrated with the
model-based application framework MASP in order to provide automated usability predictions from
early software development stages on. Finally the validity of the resulting integrated system
is confirmed by empirical data from a new application eliciting unexpected behavioral
patterns.
