1) Use drawings where necessary.

(a) Explain the concept of "mental model" and say how this concept relates to Card, Moran and Newell's "Model Human Processor".

(b) Explain the concept of interactivity and say how it relates to the idea of an interface, using examples and referring to the translations in Abowd and Beale's "Interaction Framework".

(c) Apply the Interaction Framework to a typical scenario for using a mobile phone. Say how you think task context can affect design decisions about appropriate articulations.

(d) Based on your answers to parts (a), (b) and (c) of this question and examples of your own, explain why task context and interactivity must be considered together