Human Computer Interaction Basics

Introduction about HCI

What is HCI

HCI is a study of “design of computer technology and, in particular, the interact….ion between humans (the users) and computers.” When study the HCI , We have to focus on,

Designing rules.

Evaluation rules.

Universal Design.

Designing rules

In design part, Designer use some rules for increase the usability of the eventual software product .Evaluate the design rules using the Psychological ,cognitive, ergonomic, sociological, economic, computational theory. Example of the design rules,

Learnability :- The system should be easy to use new user effectively and achieve maximal performance. Also learnability has some property ,

Predictability: support for the user to determine the effect of future action based on past interaction history.

Synthesizability: support for the user to assess the effect of past operations on the current state.

Familiarity: the extent to which a user’s knowledge and experience in other real-world or computer-based domains can be applied when interacting with a new system.

Generalizability: support for the user to extend knowledge of specific interaction within and across applications to other similar situations.

Flexibility :- The multiplicity of ways the user and system exchange information.

Dialogue initiative: user freedom from artificial constraints on the input dialog imposed by the system;

Multithreading: the ability of the system to support user interaction for more than one task at a time.

Task migratability: the ability to transfer control for execution of tasks between the system and the user.

Substitutivity: the extent to which an application allows equivalent input and output values to be substituted for each other.

Customizability: the ability of the user or the system to modify the user interface.

Robustness :- The level of support provided to the user in determining successful achievement and assessment of goal-directed behavior.

Observability: the extent to which the user can evaluate the internal state of the system from the representation on the user interface.

Recoverability: the extent to which the user can reach the intended goal after recognizing an error in the previous interaction.

Responsiveness: a measure of the rate of communication between the user and the system.

Task conformance: the extent to which the system services support all the tasks the user would wish to perform and in the way the user would wish to perform.

Heuristics and Golden Rules

Jakob Nielsen’s 10 Usability Heuristics

1. Visibility of system status: the system should always keep users informed about what is going on, through appropriate feedback within reasonable time.
2. Match between system and the real world: the system should speak the users’ language, with words, phrases and concepts familiar to the user, rather than system-oriented terms. Follow real-world conventions, making information appear in a natural and logical order.
3. User control and freedom: users often choose system functions by mistake and will need a clearly marked “emergency exit” to leave the unwanted state without having to go through an extended dialogue. Support undo and redo.
4. Consistency and standards: users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform conventions.
5. Error prevention: even better than good error messages is a careful design which prevents a problem from occurring in the first place.
6. Recognition rather than recall: make objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another. Instructions for use of the system should be visible or easily retrievable whenever appropriate.
7. Flexibility and efficiency of use: accelerators — unseen by the novice user — may often speed up the interaction for the expert user such that the system can cater to both inexperienced and experienced users. Allow users to tailor frequent actions.
8. Aesthetic and minimalist design: dialogues should not contain information which is irrelevant or rarely needed. Every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility.
9. Help users recognize, diagnose, and recover from errors: error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution.
10. Help and documentation: even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. Any such information should be easy to search, focused on the user’s task, list concrete steps to be carried out, and not be too large.

Ben Shneiderman’s 8 Golden Rules

1. Strive for consistency: layout, terminology, command usage, etc.
2. Cater for universal usability: recognize the requirements of diverse users and technology. For instance add features for novices eg explanations, support expert users eg shortcuts.
3. Offer informative feedback: for every user action, offer relevant feedback and information, keep the user appropriately informed, human-computer interaction.
4. Design dialogs to yield closure: help the user know when they have completed a task.
5. Offer error prevention and simple error handling: prevention and (clear and informative guidance to) recovery; error management.
6. Permit easy reversal of actions: to relieve anxiety and encourage exploration, because the user knows s/he can always go back to previous states.
7. Support internal locus of control: make the user feel that s/he is in control of the system, which reponds to his/her instructions/commands.
8. Reduce short-term memory load: make menus and UI elements/items visible, easily available/retrievable, and etc.

Norman’s 7 Principles

1. Use both knowledge in the world and knowledge in the head.
2. Simplify the structure of tasks.
3. Make things visible: bridge the gulfs of Execution and Evaluation.
4. Get the mappings right.
5. Exploit the power of constraints, both natural and artificial.
6. Design for error.
7. When all else fails, standardize.

Next step is

Evaluation

What is evaluation: Now we want to know how work our design and check actually behave as we expect and meet user requirements. In here , normaly we build prototype as a early stage.

Goals of the evaluation :

Evaluation has three main goals:

1. to assess the extent and accessibility of the system’s functionality: The design of the system should enable users to perform their intended tasks more easily.
2. to assess users’ experience of the interaction: The system should be easy to learn and enjoyable to user.
3. to identify any specific problems with the system: It is specifically concerned with identifying trouble-spots which can then be rectified

Evaluation through expert analysis : We can’t give our system to end user for testing ,in that case developer go to expert analysis within incomplete system or prototype. In here we will consider the three approaches,

Cognitive walkthrough : A cognitive walkthrough is a usability assessment technique in which one or more assessors work on a series of tasks and ask a series of questions from the user’s perspective.

Heuristic evaluation : Heuristic evaluation is a process where experts use rules of thumb to measure the usability of user interfaces in independent walkthroughs and report issues. Evaluators use established heuristics and reveal insights that can help design teams enhance product usability from early in development.

Model-based evaluation : Model-based evaluation is using a model of how a human would use a proposed system to obtain predicted usability measures by calculation or simulation. These predictions can replace or supplement empirical measurements obtained by user testing. In addition, the content of the model itself conveys useful information about the relationship between the user’s task and the system design

Evaluation through user participation : Now we consider technics ,for analyzing the system through analysis by the designer, expert evaluator, or an actual user.

Styles of evaluation: we can distinguish the techniques between two distinct evaluation style, those performed under laboratory conditions and work environment

Empirical methods :generally meant as the collection of a large amount of data on which to base a theory or derive a conclusion in science. It is part of the scientific method, but is often mistakenly assumed to be synonymous with the experimental method.

Observational techniques: A way of gather information how user interact with the system. In here we can get the understand how user use the system, what are the requirement to use this ,but we cant get idea about user behavior or attitude.

Query techniques : Use for get user feedback .That the best way to find How a system meet user requirements is .The advantage of such methods is that they get the user’s viewpoint directly and may reveal issues that have not been considered by the designer

Evaluation through monitoring physiological responses :One of the problems with most evaluation techniques is that we are reliant on observation and the users telling us what they are doing and how they are feeling. Potentially this will allow us not only to see more clearly exactly what users do when they interact with computers, but also to measure how they feel. The two areas receiving the most attention to date are eye tracking and physiological measurement

Universal Design

Universal Design Principles :

PRINCIPLE ONE: Equitable Use

The design is useful and marketable to people with diverse abilities.

PRINCIPLE TWO: Flexibility in Use

The design accommodates a wide range of individual preferences and abilities.

PRINCIPLE THREE: Simple and Intuitive Use

Use of the design is easy to understand, regardless of the user’s experience, knowledge, language skills, or current concentration level.

PRINCIPLE FOUR: Perceptible Information

The design communicates necessary information effectively to the user, regardless of ambient conditions or the user’s sensory abilities.

PRINCIPLE FIVE: Tolerance for Error

The design minimizes hazards and the adverse consequences of accidental or unintended actions.

PRINCIPLE SIX: Low Physical Effort

The design can be used efficiently and comfortably and with a minimum of fatigue.

PRINCIPLE SEVEN: Size and Space for Approach and Use

Appropriate size and space is provided for approach, reach, manipulation, and use, regardless of user’s body size, posture, or mobility.

Multi-modal interaction : Multimodal human-interaction refers to the “interaction with the virtual as well as physical environment”. its has five interaction methods those are sight, sound, touch, taste and smell.