2h The Model Human Processor

2h The Model Human Processor

1. Portrays user as an information processor

   • Developed by Card, Moran and Newd

2. Working memory-RAM

   • O- Both are limited
   • X- Computer can hold about 8Gb- 16Gb in RAM whereas humans can only hold about 7 items in working memory
     • X- Human has to regularly retrieve info from long-term memory making processing much slower than computers.
     • MEMORY
   • This model only considers auditory and visual inputs and stores

3. Longterm memory - Secondary storage

   • O- Both are non-volatile - Information is kept even after computer is turned off/person goes to sleep.
   • X- Computers have no difficulty storing or retrieving information from secondary storage
     • X- However, humans have to go over and memorise information a lot to store it in long-term memory and have to practice retrieving it from long term memory
       • LEARNING
   • Humans remember experiences from longterm memory

4. Perceptual processors ( sight, touch, hearing) - Inputs

   • Perceptual processor receives data from sences and sends it to the working memory.
     • At first input it is remains in the form of data and is percieved but not recognised
       • User may display initial reaction or a reflex. This can be based of like or dislike
         • PERCEPTION

5. Cognitive processors (thinking) - CPU

   • Cognitive processor- Retrieves data for auditory or image stores => recognises it using information from longterm memory, => sends instruction to motor processor
     • The amount of time needed to do this relates to ATTENTION
   • CPU- Fetch data from RAM and executes instruction

6. Motor processor (talking, typing, moving) - Output

   • Motor processor- executes instructions by telling body parts how to act and moving muscles
     • User will take time to react
   • Output device has their own processors e.g. printers

7. Timing

   • Perception processor time- Receiving data - (50-200ms)
   • Cognitive processor time- recognise and retrieve information and make a decision- (25-170ms)
   • Motor processor time- Acting out decision- (30-100ms)