HCI Prelim

Human-Computer Interaction (HCI)

A cross-disciplinary area focused on the theory

High Usability

Interactive design evaluated through correctness

Correctness

A usability criterion measuring whether users can accomplish tasks accurately.

Efficiency

A usability criterion measuring how quickly and easily users can accomplish tasks.

Safety

A usability criterion focused on preventing harmful or dangerous outcomes.

Utility

A usability criterion measuring whether a system provides the functions users need.

Learning

A usability criterion measuring how easily users can learn to use a system.

Retention

A usability criterion measuring how well users remember how to use a system over time.

User Experience (UX)

The overall personal experience a user has when interacting with a system.

UX Goal

To create systems that are satisfying enjoyable entertaining helpful motivating aesthetically pleasing and fun.

User Interface (UI)

The software and hardware through which humans interact with computers.

Software UI

Visual displays on monitors computers tablets and mobile screens.

Hardware UI

Keyboards mice and other external devices used to interact with computers.

Interaction

An abstract model through which humans interact with a device to complete a task.

Interface

The boundary where two independent systems meet and communicate or act on each other.

Interaction vs Interface

Interaction describes how humans interact with a system while an interface is the boundary through which communication occurs.

Business Impact of HCI

Usable interfaces increase productivity across industries.

Effect of Poor Interfaces

Poor interfaces can prevent users from benefiting from otherwise simple systems.

Commercial Success and HCI

Simple attractive and usable interfaces can give companies a competitive advantage and increase sales.

Spreadsheet Interface

An interface milestone that helped make business computing successful.

Web-Browser Interface

An interface milestone that enabled the growth of the Internet.

Smartphone and Mobile Interfaces

Interfaces that have become common in modern daily routines.

Body-Based Interfaces

Interfaces that use body movements as part of interaction.

Action-Oriented Interfaces

Interfaces that use physical actions and movements to control systems especially in gaming.

Know the User

The primary HCI principle emphasizing understanding the people who will use a system.

User-Centered Design

A design approach focused on users' needs characteristics abilities preferences and skill levels.

User Information

Information such as gender age education level computing experience physical capabilities mental capabilities and skill levels.

Universal Usability

Designing interfaces that can be used by a broad range of users rather than one specific group.

Universal Usability Difficulty

It is difficult to create one interface that satisfies the diverse abilities needs cultures and requirements of users worldwide.

Understand the Task

Identifying the sequence and structure of subtasks to match the user's workflow.

Subtask

An individual step or activity that forms part of a larger task.

Reduce Memory Load

Designing systems so users do not have to remember excessive amounts of information.

Short-Term Memory Capacity

About five to nine pieces of specific information according to the reviewer.

Strive for Consistency

Designing similar elements and actions to behave consistently.

Benefit of Consistency

Consistency improves familiarity accuracy satisfaction and reduces memory load.

Effect of Inconsistency

Inconsistent steps can cause confusion and errors.

Remind Users

Providing reminders or cues that refresh important information in the user's memory.

Provide Feedback

Giving users information about system actions results and current status.

System Feedback

Information produced by the system that helps users understand what happened after an action.

Prevent Errors

Designing systems to reduce incorrect actions confusion and unnecessary work.

Reversal of Action

Allowing users to undo or reverse an action they performed.

Confirmation Dialog

A pop-up that asks users to confirm an important or potentially irreversible action.

Selection Over Recall

Allowing users to select options instead of requiring them to remember and manually enter information.

Undo Button

An example of a feature that allows reversal of an action.

Natural Interaction

Interaction that reflects familiar real-world actions and processes.

Natural Interaction Examples

Nintendo Wii and Pokémon GO.

Principle

A broad high-level rule applicable across many areas of interaction design.

Guideline

A specific advisory rule used to direct actual design and development.

Principles vs Guidelines

Principles are broad and general while guidelines are specific and directly applicable.

Why Guidelines Can Conflict

Complex systems have many requirements that may compete with one another.

Jennifer Tidwell

A researcher associated with categories for organizing HCI design guidelines.

General HCI Design

A guideline category covering display layout information structure input output visualization and aesthetic design.

General HCI Design Examples

Icon sizing and color combinations.

User Type

A guideline category based on demographics target age accessibility requirements and user context.

User Type Examples

Students children older adults and visually challenged users.

Platform/System Setup

A guideline category based on hardware operating systems and system environments.

Platform/System Setup Examples

Kiosks desktops mobile devices cloud-based systems and embedded operating systems.

Vendor/Organization

A guideline category based on corporate identity branding and organizational requirements.

Vendor/Organization Examples

iOS Android Windows XP and NASA.

Interface Style/Modality

A guideline category based on interaction styles and modalities.

Interface Style/Modality Examples

WIMP non-WIMP 3D multitouch voice commands gestures and GUI widgets.

Task/Operational Context

A guideline category based on environmental conditions and operational constraints.

Task/Operational Context Examples

Office subway automobile hands-free and outdoor environments.

Applications

A guideline category addressing the needs of a specific application domain.

Application Examples

E-commerce games social networks and editing tools.

Visual Display Layout

The organization and arrangement of information and interface elements on a screen.

Visual Display Layout Guidelines

Avoid clutter consistently place key items align page elements optimize display density control line and page lengths and use frames for persistent functions.

Display Clutter

An excessive amount of information or interface elements that makes a screen difficult to understand.

Key Display Items

Important items should be placed consistently such as at the top center when appropriate.

Page Element Alignment

Aligning interface elements to improve organization and readability.

Display Density

The amount of information presented within a display area.

Line/Page Length

The length of lines and pages should be optimized for readability.

Frames

Interface areas used to keep persistent functions consistently available.

Data Entry and User Input

Designing input processes to be consistent efficient understandable and easy to perform.

Consistent Data Entry

Similar input tasks should be performed using similar actions.

Minimal Input Steps

Data entry should require as few unnecessary steps as possible.

Low Memory Load in Data Entry

Input should minimize what users need to remember.

Clearly Labeled Buttons

Buttons should have understandable labels describing their actions.

Natural Scanning Direction

Input sequences should follow the direction users naturally scan information.

Semantically Opposing Selections

Choices with opposite meanings should not be placed too close together.

Mobile Device Guidelines

Recommendations for designing interfaces specifically for mobile devices.

Rapid Status Updates

Mobile systems should quickly communicate information such as network connectivity.

Mixed Input Modes

Using multiple input methods can reduce typing and improve interaction.

Large Hit Targets

Touch targets should be large enough for accurate interaction.

Task Focus

Mobile interfaces should keep users focused on the current task.

Screen Efficiency

Mobile interfaces should make effective use of limited screen space.

WCAG

Web Content Accessibility Guidelines.

W3C

World Wide Web Consortium.

WCAG 2.1

A version of the Web Content Accessibility Guidelines used to promote accessible web content.

Four WCAG Principles

Perceivable Operable Understandable and Robust.

Perceivable

Content and interface components must be presented in ways users can perceive.

Text Alternatives

Text descriptions provided for non-text content such as images.

Adaptable Content

Content that can be presented in different ways without losing meaning or structure.

Visible and Audible Content

Text images audio and other content should be easy to see or hear when applicable.

Operable

Interface features must be usable by users.

Keyboard Accessibility

Interface functionality should be available through a keyboard when appropriate.

Sufficient Time

Users should be given enough time to read and use content.

Seizure Prevention

Content should avoid designs that can trigger seizures.

Easy Navigation

Interfaces should provide ways for users to navigate easily.

Understandable

Information and interface operation should be understandable.