11. Interaction styles

Interaction ?=? Dialogue
Interaction Styles

Command Entry

User types the commands to computer

Menus and navigation

Set of options on screen for choosing the action. Use for selecting actions or among options for data entry.
Design issues Example of a menu designer - Microsoft Word allows you to customize the manu structure and functions as you like. The structure can be stored to a file, so you can have different menus for different documents (select customize from the Tools-menu).


Form on screen with a set of fields - check-boxes - buttons - menus, for data entry of action selections. 
Typically select a set of actions or enter a set of selections and press GO (or SUBMIT or ENTER ...) 
Two basic approaches

Design issues

Direct manipulation

Basic principle
The system can have real world functions (power station, control systems) or only internal functions (drawing, calculating) 
Reasons for success
Some problems
Question - Think of a standard word processing system. How are the needs of different user groups taken into account? 

Cognitive issues of direct manipulation

Gulf of evaluation - Gulf of execution

These concepts were introduced by Hutchins et al. . 

Gulf of evaluation
the distance between the system's behaviour and the users goals
Gulf of execution
the distance between the users goals and the means of achieving them through the system

Problems in evaluation
Problems in execution
Bridging the gulf
Semantic directness
Articulatory directness

Affordance, constraints, mappings and feedback

Some design oriented issues


The tools should suggest what to do with them 
Question - What does the scroll bar suggest? 

Especially what do different parts of the bar suggest? 


Physical constraints
Restricting what the user can do (e.g. directions, dimming inactivated choices)
Connect the behaviour with known patterns (wastepaperbasket)
Question mark, thermometer scale, watch
Preserve the order of things


Arrange controls according to the objects they control 
Problem: How should the cooker control knobs be mapped on cooker rings? (Norman, 1988) 


What kind of feedback does the cooker give you if you have selected the wrong ring?