8. Actually doing something

The final part of the model human processor is the 'doing' part. It is the actions you actually carry out once you have processed the information. This is modelled as a 'Motor Processor'.

The interesting thing is you also have a kind of 'muscle memory', modelled as the 'long term muscle memory' box above. This simply means you are able to do something without having to think about it.

For example, I am typing this sentence, I see the letters form on the screen and my fingers know exactly where to go to type the next word. For someone who has not learnt to type this can take a painfully long time, but for the experienced typist, it just flows naturally.

Muscle memory is only achieved through much repetition. For example pianists, guitarists, typist or any other person with physical skill has to practice.

As an example, consider a HCI designer who for some reason has decided to use a non standard keyboard layout - a non-QWERTY one. The user will now take much longer to input text. Typically a keypad laid out in alphabetic order seems to take much longer to deal with.