Unit 2: Understanding the Human and Human Interaction

Input-Output Channels

Sensory Input: Vision, Hearing, Touch

Humans interact with computers primarily through sensory input channels like vision, hearing, and touch. These channels are vital in determining how users perceive and respond to stimuli in a system.

• Vision: The most dominant channel in human-computer interaction. Visual elements like text, images, and animations are critical in designing user interfaces.
• Hearing: Audio feedback such as alerts, sounds, or voice commands helps in improving the overall experience, especially in hands-free interaction.
• Touch: The sense of touch is engaged with devices like touchscreens, haptic feedback systems, and other tactile interfaces.

Motor Output: Response Mechanisms

Motor output refers to the actions humans take in response to stimuli. These actions could be as simple as moving a mouse or pressing a key. In HCI, systems must accommodate diverse motor skills, from highly precise movements (e.g., for professional tasks) to simpler ones (e.g., for casual browsing).

Human Memory

Types of Memory: Sensory, Short-term, Long-term

Memory plays a crucial role in human interaction with computers, as users must remember commands, navigation paths, and visual cues.

• Sensory Memory: Briefly holds sensory information, allowing users to process what they see or hear before it fades.
• Short-term Memory: Holds information for a short time, generally limited to 7±2 chunks. It is essential for tasks requiring quick decisions, such as selecting menu options.
• Long-term Memory: Stores information for extended periods. User interfaces should help users by leveraging recognition (e.g., icons) rather than recall, reducing cognitive load.

Cognitive Load

Cognitive load refers to the mental effort required to process information. When designing systems, reducing cognitive load helps users perform tasks efficiently. Simplified layouts, consistent design patterns, and clear instructions are all important strategies.

Human Emotions

Impact of Emotions on Interaction

Emotions significantly affect how users interact with systems. Positive emotions can enhance user engagement, while frustration or confusion can lead to task abandonment or errors.

• Frustration: Poor usability or lack of clear feedback can cause users to feel frustrated, negatively impacting performance.
• Delight: Well-designed interfaces that surprise or delight users can increase satisfaction and lead to greater product loyalty.

Emotional Design

Emotional design focuses on creating experiences that evoke positive emotional responses. Products that are visually appealing, easy to use, and engaging can foster strong emotional connections between users and technology.

Individual Differences

Age, Gender, Culture

Human-computer interaction varies greatly depending on individual characteristics, such as:

• Age: Younger users may be more familiar with new technologies, while older users might need more intuitive or accessible designs.
• Gender: Some research suggests that men and women may approach certain tasks differently, influencing interface preferences.
• Culture: Cultural backgrounds influence how people interpret symbols, colors, and language, making it necessary for global systems to consider diverse user bases.

Cognitive Abilities and Skills

Users have varying levels of cognitive abilities and skills, which can influence how they interact with systems. Designers must account for users with different levels of expertise, ensuring that systems are intuitive for novices while offering advanced features for experts.

Psychology

Cognitive Psychology

Cognitive psychology studies how people think, perceive, and solve problems. In HCI, it informs design decisions by understanding user mental models, task sequences, and how information is processed.

Behavioral Psychology

Behavioral psychology focuses on how users behave when interacting with systems. It helps designers anticipate user actions and create interfaces that guide users toward desired behaviors.

Ergonomics

Importance of Ergonomics in HCI

Ergonomics, or human factors engineering, ensures that systems are designed to fit human physical capabilities and limitations. In HCI, ergonomic design reduces strain, fatigue, and errors.

Design Principles for Ergonomic Products

• Physical Comfort: Keyboards, mice, and touchscreens should be designed for prolonged use without causing discomfort.
• Accessibility: Systems should accommodate users with physical disabilities, ensuring that everyone can interact effectively with technology.

Human Errors

Types of Human Errors

Humans are prone to making errors, especially when interacting with complex systems. These errors can be classified into:

• Slips: Occur when users intend to do one thing but accidentally do another (e.g., pressing the wrong button).
• Mistakes: Arise when users follow incorrect plans or have misunderstandings about how a system works.

Reducing Errors in Design

Designers can minimize human errors by incorporating features like:

• Error Prevention: Use clear labels, intuitive layouts, and confirmation prompts.
• Error Recovery: Allow users to undo actions easily or provide helpful error messages.

Models of Interaction

Norman’s Interaction Model

Donald Norman’s interaction model outlines how users interact with systems through seven stages:

1. Forming the goal
2. Forming the intention
3. Specifying the action
4. Executing the action
5. Perceiving the system state
6. Interpreting the system state
7. Evaluating the outcome

This model emphasizes the importance of feedback and understanding the user’s mental model.

Abowd and Beale’s Framework

This model breaks down human-computer interaction into four components:

1. User: The person interacting with the system.
2. Input: The method the user uses to communicate with the system.
3. Output: The system’s response to user input.
4. Interface: The medium through which interaction occurs.

Paradigms of Interaction

Command-Line Interfaces (CLI)

CLI is a text-based interface where users type commands to interact with the system. It is powerful but requires knowledge of specific commands.

Graphical User Interfaces (GUI)

GUI uses visual elements such as windows, icons, and menus to facilitate interaction. It is user-friendly and widely adopted.

Voice User Interfaces (VUI)

VUI allows users to interact with systems using voice commands, making it ideal for hands-free or multitasking scenarios.

Interaction Styles

Direct Manipulation

Direct manipulation involves interacting with objects on the screen (e.g., dragging files or resizing windows). It provides immediate feedback and is intuitive for most users.

Menu Selection

Menu selection involves navigating through lists of options. It is a simple interaction style but can become cumbersome with complex or deeply nested menus.

Form-Fill

Form-fill interfaces are common in applications where users need to enter structured data (e.g., filling out a form). Clear labels and input validation are crucial for usability.

Interactivity

Types of Interactivity

• Reactive Interactivity: The system responds to user actions (e.g., clicking a button).
• Proactive Interactivity: The system anticipates user needs and offers suggestions or actions without explicit input.

Designing for Interactivity

Effective interactive design considers:

• Feedback: Provide clear, timely responses to user actions.
• Control: Ensure users feel in control of the system, without being overwhelmed.

Context of Interaction

Physical and Social Contexts

The environment in which users interact with systems can greatly affect their experience. Physical factors include lighting, noise, and device type. Social context includes whether users are working alone or in a group.

Environmental Factors

Environmental conditions such as weather, location, or even cultural norms can influence how users interact with systems.

User Experience

Defining User Experience (UX)

User experience (UX) encompasses all aspects of a user’s interaction with a product, system, or service. Good UX ensures that the user’s needs are met efficiently and effectively.

Factors Influencing UX

• Usability: How easy it is for users to accomplish their tasks.
• Satisfaction: The level of enjoyment

or contentment users feel when using the system.

• Accessibility: Ensuring that the system can be used by people of all abilities and disabilities.