Attention : Script is not a complete representation of the oral lecture !!! 
	  Script is not yet completely finished !!!
                        

Design View

User Knowledge

It is a sound working hypotheses to assume that those internal states of a user called 'knowledge' or 'mental model' are responsible for the way a user is 'interpreting' his perceptions, is organizing his 'plans' and is selecting his 'actual actions'. Furthermore is the correspondence between the mental model and the real world environment an important factor for the number of occuring failures caused by the user.

The mental model of a user  can not directly be observed; it has to be reconstructed by observable facts as a hypothetical theoretical model which serves as an interpreting model of the behavior of a user.

The mental model is highly dynamic; it has to be constructed by sequences of certain actions ('learning'), but it can again 'fade away' ('forgetting').