18 2 TheProblemsofDesign and a visual image store. While it is being symbolically encoded, the output of the sensory system is retained. The cognitive system receives information symbolically coded from the perceptual system that contains the sensory image stores in its working memoryandemploysinformationpreviously stored in long-term memory to decide about how to react. The motor system then carries out the responses. Thereis a separate processor in each subsystem: a perceptual processor, a cognitive processor and a motor processor, which have a capacity for both serial and parallel processing. The cognitivist view considers that users act rationally to obtain their goals. On this base,wecanpredictauser’sbehaviourbydeterminingtheuser’sgoals,methods andoperatorsandtheconstraintsofthetask.ThishasbeenformulatedintheGOMS approach,whichhelpspredict user’s behaviour,based on the assumption that underlying the detailed behaviour of a particular user there are a small number of information processing operators, that the user’s behavior is describable as a sequence of these, and that the time the user requires to act is the sum of the time of these individual operators. (Card et al. 1983, p. 139) The GOMS model specifies the components that a user’s cognitive structure is supposed to be composed of: a set of goals, a set of operators, a set of methods for attaining the goals, and a set of selection rules for choosing appropriate methods for goals. By this and similar approaches, HCI largely concerns itself with the complexenvironmentalconditionsin which humansare put into motion via stimuli (as inputs received by the brain). Their behavioursare responsive outputs generated by the nervous system. The human “operator” is essentially seen as a computing environmentinteracting with another, external computing environment. We can find challenging and interesting applications for educational, medical and industrial usage designed on the basis of such basically mechanical principles, but many are not at all suitable for actual people, and especially not for people with special needs. People, as human beings, are forced to adapt to the external computing environment based on mechanistic principles, even though human behaviours can be seen instead as essentially a natural flow of action based on constant activity. In this kind of approach, design is rational to the extent that a designer is being objective. TheHuman-UserDichotomy HCIdesignershistorically sought a new concept of “user interfaces”, especially for officeworkers,sincecomputeruserswerehistoricallyalmostallofficeworkers.The designers therefore tried to evoke explicitly people’s knowledge of office work to help them understand the operation of the computer. The typical design approach to HCI design used metaphor in order for users to understand how to use a computing system (Imaz and Benyon 2006; Waterworth et al. 2003). This encompasses what users feel, think, and are able to do as they interact, and has often been called User-Experience Design in the last few years.