Human-Computer Interaction - user’s knowledge structure - Prof. dr. Matthias Rauterberg Faculty of Technology Management Technical University Eindhoven The Netherlands

The fundamental design problem designer’s mental model user’s mental model perceived semantic intended semantic perceivable user interface forms implemented functions © M. Rauterberg, TU/e

What is Human-Computer Interaction about? Working domain Goal: Actual Performance => Desired Performance Working system user system © M. Rauterberg, TU/e

Three different function types Secondary functions [dialog manager] Tertiary functions [dialog manager] Primary functions [application manager] Application object(s) © M. Rauterberg, TU/e

The User Interface (1) user action perception input/output interface presentation dialog module dialog dialog dialog state objects functions application application module state application application transformation functions objects user interface © M. Rauterberg, TU/e

The User Interface (2) [further reading] input-handler output-handler Long-term memory action module input operation visual "memory" visual output presentation dialog module dialog state application transformation user interface objects (AO) application module objects (DO) funcrtions functions auditory auditory output tactile tactile output perception module motor memory goal problem solving module Short-term memory learning user expectation plan system [further reading] © M. Rauterberg, TU/e

Several Notions of ‘Models’ [Horst Oberquelle, 1984] © M. Rauterberg, TU/e

User’s Mental Models [Stephan Dutke: Mental Models-constructs of knowledge and understanding, 1994] external stimuli Interface elements perception e.g. visual system mental structure cognition e.g. Action Cycle action e.g. Fitts Law © M. Rauterberg, TU/e

The Difference between Internal and External Memory the mental model of the user about the external world is always incomplete all necessary information which is not in the internal memory must be provided by the environment (the “external memory”) © M. Rauterberg, TU/e

Knowledge in the World and in the Head © M. Rauterberg, TU/e

User’s motor behavior: Fitts' Law T = k log2(D/S + 0.5) with k ~ 100 msec T = time to move the hand to a target D = distance between hand and target S = size of target Fitts' Law is a model to account for the time it takes to point at something, based on the size and distance of the target object. Fitts' Law and variations of it are used to model the time it takes to use a mouse and other input devices to click on objects on a screen. Fitts' Law can be applied by designers to suggest moving target buttons closer and making them larger for extremely commonly used buttons. In detail, applying the formula can be extremely useful for exact design of time-critical applications. © M. Rauterberg, TU/e

The Visual Perception System © M. Rauterberg, TU/e

Activity Theory: the Complete Action Cycle task(s) goal-, subgoal-setting feedback planning of execution control of action selection of means mental operation physical operation © M. Rauterberg, TU/e

User’s model: activity cycle task description cognitive process Cognitive level feedback Feedback level goal instanciation Goal instanciation level observable action Action level [further reading] © M. Rauterberg, TU/e

User’s mental structure Regulation-driven goal setting Cognitive level System level instanciation Goal level Feedback level [further reading] Action level F_10 G_2 M_3 h F_3 1 i h MsDOS Start menu Main menu © M. Rauterberg, TU/e Main menu F-file

How to investigate the user’s mental model? © M. Rauterberg, TU/e

User’s learning process We (1996) found a negative correlation between Behavioral-Complexity and Mental-Complexity [further reading] © M. Rauterberg, TU/e

mental activity is like the ‘flow of a river’ © M. Rauterberg, TU/e

Learning means ‘digging’ learning process [further reading] © M. Rauterberg, TU/e

User’s Behavior: an example "dales" of knowledge about successful behavior s0 d h "wall" of knowledge about unsuccessful behavior s1 CR b F9 F2 s2 F3 s3 TAB _ © M. Rauterberg, TU/e

User’s real knowledge structure knowledge about unsuccessful behavior knowledge about successful behavior © M. Rauterberg, TU/e

Thank you for your attention More at my homepage © M. Rauterberg, TU/e