Design Principles and Interaction Model

Design Principles

• Donald Norman's design principles aim for intuitive user interfaces
• Key principles include affordances (design clearly indicating purpose), minimizing the Gulf of Interpretation and Execution (reducing gaps between user expectations and actions), using natural mappings (intuitive controls), making state visible (keeping users informed of system status), providing feedback (informing users of action outcomes), and using a clear conceptual model (understandable system workings) to enhance user experience.

Norman's Model of Interaction

• Norman's seven stages of interaction are:
  • Establishing the goal (e.g., turning on a light, buying a product online)
  • Forming the intention (e.g., planning to press a switch, using website search)
  • Specifying the action sequence (e.g., pressing the switch, entering keywords, clicking "Add to Cart")
  • Executing the action (e.g., pressing the switch, interacting with website search)
  • Perceiving the system state (e.g., seeing the light turn on, viewing search results)
  • Interpreting the system state (e.g., determining if the light works, assessing search results relevance)
  • Evaluating the system state (e.g., determining sufficient lighting, confirming product addition to cart)

Design Challenges and Implications

• Design complexity results from an explosion of controllable elements, a shift towards virtual displays, increasing marketplace pressure, and growing design error consequences.
• Making current states and action alternatives visible addresses the gulf of interpretation.
• A good conceptual model with consistent system image addresses the gulf of execution.
• Mappings revealing relationships between stages address both gulfs.
• Continuous feedback addresses the gulf of interpretation

Idea Creation in Design Process

• Idea generation methods include finding new uses, adapting, modifying, magnifying/adding to, minimizing/subtracting, substituting, rearranging, changing viewpoint and combining data.

Conceptual Model in Design

• A good conceptual model allows users to develop a mental model of how a system works.
• Aligning the design with this mental model enables intuitive interaction and prediction of action effects.

Design Principles (Continued)

• Emphasizing simple and natural dialogue reduces jargon and ensures intuitive interactions.
• Maintaining consistency in design improves usability by reducing cognitive load.
• Providing informative feedback enhances user control and understanding of actions.
• Minimizing memory load using recognition over recall improves user experience.

Short-Term Memory

• George Miller's theory suggests short-term memory can hold approximately seven (plus or minus two) chunks of information.

Command Line Interfaces (CLIs)

• CLIs use text commands for interacting with a system.
• They are efficient for automation and scripting, but require learning specific commands.
• CLIs are valuable for web scripting and document editing.

Graphical User Interfaces (GUIs)

• GUIs utilize visual elements like windows, icons, and menus for user interaction.
• GUIs enhance usability by using pointing devices, but may be less efficient than CLIs for specific tasks.

Windows and Menus in GUIs

• Windows improve usability for simultaneous viewing and task management.
• Different GUI menu styles (e.g., flat lists, drop-downs, pop-ups, collapsible menus) offer varying space efficiencies.
• Icons improve interaction through visual representations of commands and tools, enhancing user experience.

Icon Design Considerations

• Clear mapping between icons and their functions is crucial for immediate recognition and understanding.
• Consistent icon design across different screens enhances usability.

Multimedia in Interfaces

• Multimedia interfaces combine various media types (graphics, text, audio, video) to create interactive experiences.
• Multimedia enhances engagement, presentation, and learning styles.

Virtual Reality (VR) Interfaces

• VR interfaces offer immersive experiences, a sense of presence, and enable interactive applications in gaming, training, and virtual tours.

Interaction Types and Interface Styles

• Interaction Types describe user actions (instructing, responding etc).
• Interface Styles are the methods supporting interaction (command-based, menu-based, gesture-based, voice-based, etc).

Conversational Interface Model

• The conversational model facilitates interactions in a familiar way.
• Voice assistants are an example, but misunderstandings can occur.

Direct Manipulation Interaction

• Direct manipulation provides quick learning, efficient task completion, good retention, and a strong sense of control.
• Limitations include potential misinterpretations, not all tasks being suitable for this approach, potentially-space-consuming elements, and potentially slower interaction for some actions than keyboard shortcuts.

Exploring as an Interaction Type

• Exploring involves navigating virtual or physical environments.
• This interaction type actively engages users in their surroundings.

System-Initiated Notifications

• System-initiated notifications are alerts triggered by the system based on user behavior or context (location, past actions).
• They help proactively inform the user of relevant information.

Website Design Considerations

• Website design must prioritize clear information architecture for easy navigation and balance aesthetics and usability.

Web Design Styles

• Responsive design adapts to different screen sizes.
• Infinite scrolling offers continuous scrolling without page breaks.

Mobile Interface Considerations

• Design for varying user dexterity levels, appropriate target sizes (touch targets), and screen sizes.
• Minimizing cognitive load, and using easily usable navigation methods are crucial.

Voice Interface

• Voice interfaces use spoken language for interaction.
• They're effective for information requests and transactions but reliant on speech recognition accuracy.

Multimodal Interfaces

• Multimodal interfaces combine diverse input and output methods (touch, sight, sound, speech) for more expressive interactions.

Prototyping Techniques

• Prototyping helps in evaluation, feedback, communication, testing and improving design.
• Low-fidelity prototypes are quick and simple, with methods like sketching, index cards, and storyboards

High-Fidelity Prototyping

• High-fidelity prototypes mimic the final product visually and functionally.

Co-Design

• Co-design emphasizes shared creativity and learning.
• Collaboration with multi-disciplinary teams is crucial throughout the design process.

Keystroke Level Model (KLM)

• KLM is a part of GOMS, that analyzes the execution phase of user actions
• KLM includes operators related to physical motor actions (keystrokes, pointing, etc.) and mental processes.
• Execution times for these actions are empirically determined.