Basic Concepts of Human-Computer Interaction
Prof C. Tasso
University of udine
The study of human-computer dialogue represents a theoretical approach and aims to provide with general principles for the development of user interfaces.
Human-Computer Dialogue
Dialogue
is defined as"a temporally limited interaction between two or more relatively autonomous communicating entities through a sequence of exchanged messages."
Linguistic knowledge can be divided into three different levels:
the lexical level, which refers to the specific elements to be used in order to construct the messages of dialogue,
the syntactic level, which specifies how these elements have to be correctly arranged in order to build a message and, finally,
the semantic level, which refers to the meaning of the messages exchanged in the interaction.
the pragmatical level, which refers to the use of the language in order to accomplish the specific goals of the user, that is, it relates goals to sentences.
Context
The context consists of the general framework including all the explicit and implicit information referred to during the whole dialogue.
Reciprocal understanding <==> context sharing
Control
Control
refers to the rules which govern the initiative in leading dialogue:- user-driven dialogue,
- system-driven dialogue,
- mixed-initiative dialogue,
Styles
A style refers to the kind of objects utilized during the interaction and the way they are arranged.
- natural language
- command language:
- direct manipulation
- menu
- form filling
- window environment
- iconic
- graphical interaction
Mental Models
Mental models
are abstractions of the entities of the domain which they represent and they are used by each agent participating in a dialogue in order to reason about the considered domain and to understand the other agents of dialogue.- clarity in representing the relevant concepts of the domain and their relations,
- coverage of the domain, and
- level of abstraction in representing the domain concepts.
For each agent in the dialogue:
- world models, which refer to general knowledge of the world;
- task models, which represent the specific domain knowledge about the tasks to be done;
- models of self, which refer to the personal characteristics, goals, intentions, preferences, temporary states, etc. of the agent.
Mutual Knowledge
- computer model, represents the user's model about the functioning of the computer system;
- user model, represents the computer's model about the user's state of knowledge and it refers to the knowledge, intentions, goals, preferences, etc. of the user.
Novice models
The extent to which a user interface promotes accurate mental models should be a primary and fundamental factor of whether or not an interface can be classified as a good and friendly interface.
In essence, a good interface should be able to inspire good mental models (this aspect addresses good interface design, help facilities, on-line tutorials and good documentation).
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Different users ==> UI with different User Models
==> adaptive UI ( ===> User Modeling)
==> adaptable UI
Metaphor
Sometimes related domains can be exploited for helping the user to develop a new model.
Es.: desktop metaphor
The scope of a metaphor consists in the amount of concepts referred to by the metaphor, that is, it represents the set of concepts which the metaphor aims to explain to the user.
The level of description of a metaphor refers to the type of information that the metaphor is expected to communicate, i.e. an indication of one or more of the three standard levels of communication (i.e. lexical, syntactic and semantic).
Errors
Different kinds of causes:
...
mispelling
mismatch in the mental models
bad mapping between what the user can control and what he wants to do
system has altered state, but the user cannot easily recognize the change
...