HUMAN INFORMATION PROCESSING Human Information Processing Predictive Performance Assessment: GOMS (Goals, Operators, Methods and Selection) • Many Important Cognitive Activities has been analyzed in terms of their typical approximate process time; for single-chunk retrieval from shortterm memory, encoding (memorizing of information into the long-term memory, responding to a visual stimulus and interpreting it’s content, etc. Human Information Processing Table 3.1 and 3.2 illustrate such an example based on the framework called GOMS ( Goals, Operators, Methods, and Selection). Table 3.1 Estimate of Time Taken for Typical Desktop Computer Operations from GOMS TYPES OF OPERATIO K: Keyboard input Time ESTIMATE Expert: 0.12 s Average: 0.20 s Novice: 1.2 s T(n): Type n characters 280 x n ms 280 x n ms P: Point with mouse to something on the 100 ms display B: Press or release mouse button 100 ms Human Information Processing BB: Click a mouse button (press and release) 200 ms H: Home hands, either to the keyboard or mouse 400 ms M: Thinking what to do (mental operator) 1200 ms (can change) W(t): Waiting for the system (to respond) tms Human Information Processing Table 3.2 Estimate of Time Taken for Two Task Models of “Deleting a File” DELETING A FILE DESIGN 1 1. Point to file icon 2. Click mouse button 3. Point to file menu 4. Press and hold mouse button 5. Point to DELETE item 6. Release mouse button DESIGN 2 P BB P B P B 1. Point to file icon P 2. Click mouse button BB 3. Move hand to keyboard M 4. Hit command key; KK command-T 5. Move hand back to mouse H Human Information Processing 7. Point to original window Total time= 4.8 s P Total time= 2.66 s Note: The total time is computed by adding the corresponding figures in Table 3.1. Design 2 is the “expert” version that uses a hot key [7]. The original GOMS model was developed mainly for the desktop computing environment, with performance figures for mouse clicks, keyboard input, hand environment, and mental operators. Human Information Processing GOMS is quiet simple in that it can only evaluate in terms of the task performance, while there are many other criteria by which an HCI design should evaluate. Sensation and Perception of Information The processes of sensation and perception in the four major modalities and the associated human capabilities in this regard. Just as cognitive science was useful in information and the task modeling, this knowledge is essential in sound Human Information Processing interface selection and design.