Common Interface Interaction Styles
June 24, 2008
Command Driven
This was one of the earliest forms of communication with the computer. The command language system offers a prompt which can range from a .(dot) to a word or a short phrase. The drawback is that users have to remember the commands they want.
Menu
This is a set of options displayed on the screen. It has the advantage that the user does not have to remember anything, but merely to recognize it. Designers have to decide the best way of displaying menus so that they are comprehensible and natural to use.
There are 4 reasonable alternatives for ordering menu items.
- Alphabetical
- Categorical i.e. selection of suitable categories
- Conventional i.e. sticking to pre-ordained order.
- frequency of use.
Menus are supportive, but do not provide flexibility. The number of entries in a menu should not be too many. If too many, you should consider sub-categories.
Question and Answer dialogs
In such systems the system pauses a question to the user and the action carried out depends on the input. This type of systems are used in tasks where information is elicited from users in a prescribed and limited form such as ATM’s, catalog and scheduling applications.
They protect the user from any considerations of navigation and are suitable for novice users, thus they are supportive and offer flexibility.
Forms
The system decides the nature of a pre-determined sequence of inputs and displays simultaneous requests for a completed set of inputs.
There are two types of forms:
a) Those which are designed for transcription input i.e. the screen matches the document the user is working from.
b) Forms without corresponding documents
This input style is very supportive; error trapping should be possible in a carefully designed form.
Natural Language Dialog
This promises flexibility and naturalness of interaction, it is still not possible to have a system that fully understands natural language as it is typed.
Direct manipulation vs Linguistic Manipulation (command driven) using painting devices
Direct Manipulation
These type of interaction provides a continuous graphical representation of current objects of interest that are physically manipulated by some sort of pointing device. The advantage of this is:
a) Novices can learn the basic functionality quickly
b) Experienced users can work extremely fast to carry out a wide range of task.
c) There is reduced anxiety on the part of users.
d) Users gain confidence and mastery because they initiate action, feel in control and can predict system responses.
e) It leads to reduced memory load on the user since whenever a task needs to be performed an examination of the system will tell the user what needs to be done.
Linguistic Manipulation:
Linguistic manipulation system consists of issuing commands and providing labels for objects which those commands will operate on. Their major drawback is that they put considerable pattern on the user of the system since the commands have to be learned and cannot be deduced from interacting with the system. However, they can be very efficient and powerful once learned.
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