Deep insights of Human Computer Interaction

Human-computer interaction (HCI) is a multidisciplinary field of study focusing on the design of computer technology and, in particular, the interaction between humans (the users) and computers. While initially concerned with computers, HCI has since expanded to cover almost all forms of information technology design.

There is few important parts in Human Computer Interaction.Let’s Talk about them.

Design rules for Interactive Systems

Main goal of interactive systems design is to designing for maximum usability. Design rules in the form of standards,guidelines and principles provide with a direction for design, in both general and more concrete terms, in order to enhance the interactive properties of the system.

Principles of Learnability

1.Predictability

This interactive design principle requires a user’s knowledge of interaction to be sufficient to determine the outcome of present or future interaction with the system.

Ex : Closing a document should always allow the user to save changes not saved already

2.Consistency

This principle tells the use of labels and icons should always be consistent and the same icons and labels should mean the same thing.

Ex : Using standard and consistent icons for things like home,notification, add, delete.

3.Synthesisability

This principle relate to the ability of the interactive system to provide the user with an observable and informative notification about the operation state changes within the system.

Ex : Moving a file from one folder to another is observable by the user in Windows, however, carrying out the same operation in DOS provides no visual representation of the system’s actions.

4.Familiarity

The familiarity principle is concerned with the ability of an interactive system to allow a user to map prior experiences, either real world or gained from interaction with other systems, onto the features of a new system.

Ex : Using Recycle bin icon suggest its function ,Using Red color to show warnings.

5.Generalizability

This principle provides support for users to extend knowledge of specific interaction within, and across applications, to new, but similar situations

Ex : cut/copy/paste operations within Microsoft Office applications use of same short-cut keys

Principles of Flexibility

1.Dialog initiative

Dialog initiative means freedom from system imposed constraints on input dialogue.

2.Multi-threading

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

3.Task migratability

Task migratability means passing responsibility of execution of tasks between user and system.

Ex : Computerized Spell Checker which saves user time by auto correcting spelling mistakes.

4.Substitutivity

Substitutivity means offering user alternative ways of specifying input or viewing output.

Ex : drawing package may allow start and end co-ordinates of a line to be specified, conversely, the same system may allow the line to be drawn first

5.Customizability

Every user has his own preference. So the user interface should be able to support each individual preferences.

Ex : Amendable control bars in MS Word.

Principles of Robustness

1. Observability

Observbility means providing users with an ability to evaluate the internal state from its representation.

Ex : Web browser showing the ongoing status of a page download.

2.Recoverability

Users should be able to reach a desired goal after recognition of errors in previous interaction in either forward (negotiation) or backward (undo) ways.

Ex : Undo a delete line in word document.

3.Responsiveness

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

4.Task conformance

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

Standards and Guideline for Interactive systems

• Standards

Standards are set by national or international bodies to ensure compliance by a large community of designers to standardize the look and feel of a user interface and for a smooth the HCI design process.

Ex : ISO Standards, National Standards provides by institutes like American National Standards Institute , British Standards Insititution, Ente Nazoline Italiano Di Unificazoine

• Guidelines

Guidelines are more suggestive and general and there is many textbooks and reports full of guidelines.

Ex : Abstract guidelines applicable during early life cycle activities , Detailed guidelines (style guides) applicable during later life cycle activities, Understanding justification for guidelines aids in resolving conflicts.

Shneidermans’s 8 Golden Rules

These Rules were introduced by Dr. Ben Shneiderman of university of Maryland in 1980s.These 8 Rules provides Useful guide to Students & Designers. These rules require validation and tunning for specific design domains.

1. Strive for consistency
2. Enable frequent users to use shortcuts
3. Offer informative feedback
4. Design dialogs to yield closure
5. Offer error prevention and simple error handling
6. Permit easy reversal of actions
7. Support internal locus of control
8. Reduce short-term memory load

Norman’s 7 Principles

These Principles were introduced by American researcher Don norman in 1988.

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 .

Evaluation techniques for interactive systems

What is Evaluation?

Evaluation is the Process which assesses the design and test the systems to ensure they perform as the requirement. It involves collecting and analyzing information about a program’s activities, characteristics, and outcomes.

Goals of Evaluation?

• Assess the extent and accessibility of the system’s functionality.
• Finding any specific problems with the system and fix them before deployment.
• Determine how usable system is for different user groups.
• Identify good and bad features to inform future design.
• Compare design choices to assist us in making decisions.
• Observe the effects of specific interfaces on users.

Evaluation through expert analysis

In expert-based evaluation, a designer or HCI expert assesses a design based on known standard cognitive principles or empirical results. Expert-based evaluation techniques are also referred to as expert analysis techniques.

Let’s Talk about few Experts based evaluation techniques.

Cognitive walkthrough

In cognitive walkthrough method one or more HCI experts or Designers performs a series of tasks and ask a set of questions from the perspective of the user to evaluate the design and user interaction.

To perform a cognitive walkthrough following are required,

• A specification or prototype of the design
• Description of the task the user is to perform
• Written list of the actions needed to complete
• An understanding about who the users are and what they need from the system is required.

Heuristic evaluation

In Heuristic evaluation, Evaluators goes through the design independently based on selected heuristics and comes up with the usability issues they found and thereby making them addressable and solvable.

Effectiveness of a heuristic evaluation depends on two things,

• Evaluators
• Selected Heuristics

There are many types of Heuristics used for a heuristic evaluation. The Most famous one is “Jacob Nielsen’s 10 Usability Heuristics for User Interface Design”

Jacob Nielsen’s 10 Usability Heuristics for User Interface Design

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. Model based evaluation is combining
cognitive and design models to evaluation process.

Models used for model based Evaluations,

• GOMS model
• Keystroke-level model
• Design rationale
• Dialog models

Evaluation through user participation

Instead of using HCI experts or Designers, the real users are used in this method. This method of evaluation tends to used in the later stages of development. This may range from a simulation of the system’s interactive capabilities, without its underlying functionality.

Let’s Talk about few User based evaluation techniques.

Styles of evaluation

There is two Styles of evaluation based on conditions and environment.

Laboratory studies

• In this type of studies users are taken out of their normal work environment to take part in controlled tests in laboratory like environment with sophisticated audio/visual recording and analysis facilities.

Field studies

• This type of evaluation takes the designer or evaluator out into the user’s work environment in order to observe the system in action.

Empirical methods: experimental evaluation

This provides empirical evidence to support a particular claim or hypothesis. The evaluator chooses a hypothesis to test. Any changes in the behavioral measures are attributed to the different conditions.

There are number of factors that are important to the overall reliability of the experiment.

1. Participants

Represent the set of people who going use for the experiment. Since choice of participant in vital to the success participants should be chosen to match the expected user population as closely as possible

2. Variables

Represent things to modify and measure in the evaluation. There is two types of variables, independent and dependent variables.

3. Hypothesis

A hypothesis is a prediction of the outcome of an experiment. It is framed in terms of variables. The aim of the experiment is to show that this prediction is correct, this is done by disproving the null hypothesis.

4. Experimental design

This design represent the the process of doing the evaluation.There are two main methods.

Once you gather the data you need to analyze the data. You need to identify the type of data, discrete or continuous and then according to that you need analyze the data using statistical methods.

Observational techniques

1.Think Aloud

In this method user asked to describe what he is doing and why, what he thinks is happening. This method requires little expertise ( simplicity ) and provides useful insight and shows actual use of system.But this method is can’t be used in every scenario.

2.Cooperative Evaluation

In this method user and evaluator collaborates and ask each other questions throughout.This is constrained and easier to use.Also user encourage to even criticize the system.

3.Protocol Analysis

Methods for recording user actions in protocol analysis,

• paper and pencil — cheap, limited to writing speed
• audio — good for think aloud, difficult to match with other protocols
• video — accurate and realistic, needs special equipment, obtrusive
• computer logging — automatic and unobtrusive, large amounts of data difficult to analyze
• user notebooks — coarse and subjective, useful insights, good for longitudinal studies
• Mixed use in practice.
• audio/video transcription difficult and requires skill.
  Some automatic support tools available

4. Automated Analysis

Analyzing protocols, video, audio or system logs is time consuming and tedious by hand but automatic analysis provide tools like EVA ( Experimental Video Annotator ) which is a system that runs on a multimedia workstation with a direct link to a video recorder to support the task.In Automated Analysis analyst has time to focus on relevant incidents and avoid excessive interruption of task.

5.Post-task walkthrough

In this method user reflects on action after the event. This provides analyst time to focus on relevant incidents and avoid excessive interruption of task.But this method lack freshness.

Query techniques

1. Interviews

In this Method Analyst questions user on one to one basis with prepared questions about his experience with the design. This method is informal,subjective and relatively cheap compared to other methods. But it is more time consuming than other methods.

2. Questionnaires

In this method users are given a set of fixed questions about what they prefer and what they think about the design.This method gives chance to reach big group of people in less time.But this is less flexible and less probing.

Evaluation through monitoring physiological responses

Eye Tracking

In Eye tracking method position of the eye is track through head or desk mounted equipment. Using that equipment the following measurements are taken and by analyzing those measurements the evaluation is conducted.

Fixations : eye maintains stable position.

• Number of fixations — The more fixations the less efficient the search strategy
• Fixations duration — Indicate level of difficulty with display

Saccades : rapid eye movement from one point of interest to another
Scan paths : moving straight to a target with a short fixation at the target is optimal

Physiological Measurements

In this method users emotions and physical changes when using the user interface is observed and based on those data the evaluation is conducted.

Following are such changes observed in the process,

• Heart activity, including blood pressure, volume and pulse.
• Activity of sweat glands : Galvanic Skin Response (GSR)
• Electrical activity in muscle : electromyogram (EMG)
• Electrical activity in brain : electroencephalogram (EEG)

Universal Design for Interactive Systems

Universal Design Principles

In 1997 working group of architects, product designers,engineers led by Ronald Mace in the North Carolina State University developed 7 Principles of Universal Design for Interactive Systems. The purpose of the Principles is to guide the design of environments, products and communications. These principals may be applied to evaluate existing designs, guide the design process and educate both designers and consumers about the characteristics of more usable products and environments.

1.Equitable Use

The design is useful and marketable to people with diverse abilities. For example, a website that is designed to be accessible to everyone, including people who are blind and use screen reader technology, employs this principle.

2. Flexibility in Use

The design accommodates a wide range of individual preferences and abilities. An example is a museum that allows visitors to choose to read or listen to the description of the contents of a display case.

3. 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. Science lab equipment with clear and intuitive control buttons is an example of an application of this principle

4. Perceptible Information

The design communicates necessary information effectively to the user, regardless of ambient conditions or the user’s sensory abilities. An example of this principle is captioned television programming projected in a noisy sports bar.

5. Tolerance for Error

The design minimizes hazards and the adverse consequences of accidental or unintended actions. An example of a product applying this principle is software applications that provide guidance when the user makes an inappropriate selection.

6. Low Physical Effort

The design can be used efficiently, comfortably, and with a minimum of fatigue. Doors that open automatically for people with a wide variety of physical characteristics demonstrate the application of this principle.

7. Size and Space for Approach and Use

Appropriate size and space is provided for approach, reach, manipulation, and use regardless of the user’s body size, posture, or mobility. A flexible work area designed for use by employees who are left- or right-handed and have a variety of other physical characteristics and abilities is an example of applying this principle.

Multi-modal interaction

If you follow the multi-modal interaction model your system will be able to provide information to the user through more than one sense which is a must in a good system. Mainly Multi-modal interaction covers the five senses namely sight, sound, touch, taste and smell. Although taste and smell are stated currently those senses are not used in the software world.

Sound in the interface
Sound is an important contributor to usability. There is experimental evidence to suggest that the addition of audio confirmation of modes, in the form of changes in keyclicks, reduces errors. The dual presentation of information through sound and vision supports universal design, by enabling access for users with visual and hearing impairments respectively. It also enables information to be accessed in poorly lit or noisy environments. Sound can convey transient information and does not take up screen space, making it potentially useful for mobile applications.

Touch in the interface
Touch is the only sense that can be used to both send and receive information. The use of touch in the interface is known as haptic interaction. Haptics is a generic term relating to touch, but it can be roughly divided into two areas: cutaneous perception, which is concerned with tactile sensations through the skin; and kinesthetics, which is the perception of movement and position.

Handwriting recognition
Like speech, we consider handwriting to be a very natural form of communication. The idea of being able to interpret handwritten input is very appealing, and handwriting appears to offer both textual and graphical input using the same tools. There are problems associated with the use of handwriting as an input medium.

Gesture recognition
Gesture is a component of human–computer interaction that has become the subject of attention in multi-modal systems. Being able to control the computer with certain movements of the hand would be advantageous in many situations where there is no possibility of typing, or when other senses are fully occupied. It could also support communication for people who have hearing loss, if signing could be ‘translated’ into speech or vice versa.

Designing Interfaces for diversity
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Interfaces are usually designed to cater for the ‘average’ user, but unfortunately this may exclude people who are not ‘average’. There are three main areas to be considered in this context namely disability, age and culture.

Disability
When designing interfaces in the context of a disability, sensory, physical and cognitive senses must be taken into account. Systems should provide a good form of communication for the visually impaired. Indeed, if you have hearing loss, computer technology can improve communication for deaf people. E-mail and instant messaging are great organizational tools and can be used by both hearing and deaf users. Speech and visual recognition systems can be added to systems to help people with disabilities.

Age
In this context, older people and children have specific needs when it comes to interactive technology. The requirements of the older population may differ significantly from other population groups, and will vary considerably within the population group. Mobile technologies can be used to provide memory aids where there is age-related memory loss. Like older people, children have distinct needs when it comes to technology, and again, as a population, they are diverse. It is therefore important to involve them in the design of interactive systems that are for their use, though this in itself can be challenging as they may not share the designer’s vocabulary or be able to verbalize what they think.

Culture
Cultural difference is often used synonymously with national differences but this is too simplistic. Factors such as age, gender, race, sexuality, class, religion and political persuasion, may all influence an individual’s response to a system. This is particularly the case when considering websites where often the explicit intention is to design for a particular culture or subculture.