Introduction to Human-Computer Interaction (Part 2)

The Design Pillars

As mentioned in part 1, designers should focus on who the users are, what activities they are doing, and where the interaction is taking place.

Who are the users?

You need to analyze the

  • Demographics and Background of the users
  • Their Capabilities and Requirements

Understanding these factors allows you to create Tailored Interfaces for the users and lead to Error Prevention by causing fewer mistakes and frustrations.

What activities are performed?

Designers must make a Detailed Examination of the tasks. They also understand the Task Spectrum (Difficulty ???).

What Activities are Performed?

Designers should analyze all of the following for the interaction

  • Location and Environment
  • Environmental Factors
  • Physical Constraints

The Interaction Design Process (The Iterative Approach)

Summary of the interactive design process:

  • Goal: Create systems that are effective, efficient, and satisfying
  • Methodology: A continuous, non-linear cycle of refinement
  • Core Philosophy: Constant evolution through understanding, designing, prototyping, and evaluating

The interactive design process is an iterative cycle of the following 4 phases. You keep repeating this cycle until the system is ready. The goal is to find the balance between usability, usefulness, and satisfaction.

Phase 1: Identify Needs & Requirements

Here, the focus is on determining user goals, specific tasks, and the operational context through user research, interviews, observations, and task analysis. The outcome is a clear set of functional, usability, and experiential requirements.

Phase 2: Develop Alternative Designs

Here, you create and explore multiple solutions through sketches, storyboards, and conceptual models. This encourages divergent thinking and creativity to explore various approaches. The goal is to compare different ideas and select the most appropriate one.

Phase 3: Build Interactive Prototypes

Here, you create versions of the system that allow users and stakeholders to experience the design early. There is a wide range of possible prototypes from low-fidelity paper sketches to high-fidelity interactive simulations. The goal of this phase is to uncover usability issues and clarify functionality.

Phase 4: Evaluate Design Continuously

Here, you refine the design through user feedback.

Usability Goals

Usability goals define how effectively a system supports users in completing tasks and achieving objectives. They prioritize the practical aspect of human-computer interaction.

These goals are:

  • Effectiveness: accuracy and completeness with which users achieve their goals
  • Efficiency: Speed and effort required to perform specific tasks.
  • Safety: ability to prevent errors or mitigate their consequences
  • Utility: extent to which a system provides the necessary functions to meet user needs
  • Learnability: How easy it is for new users to accomplish tasks and become proficient
  • Memorability: How easily users can remember how to use the system after a period of non-use

User Experience Goals

UX goals focus on the emotional and psychological responses that arise during interaction with a system. They prioritize enjoyment and satisfaction.

  • Enjoyable
  • Fun
  • Motivating
  • Aesthetically Pleasing
  • Emotionally Fulfilling
  • Not just used, but valued by the user

Design Principles

Design principles provide general guidelines that help interaction designers create effective, efficient, and satisfying systems. Common design principles are:

  • Visibility: Make what has to be done obvious for the user

  • Feesback: Send information back to the user about what has been done

  • Constraints: Restrict the possible actions that can be performed. 3 types of constraints:

    • Physical

    • Cultural

    • Logical

  • Mapping: Make a clear relationship between the controls, their movements, and their result in the world.

  • Consistency: Similar tasks should use similar elements and similar interfaces. Could be both internal and external/

  • Affordance: Refers to an attribute of an object that allows people to know how to use it

    • a mouse button invites pushing, a door handle affords pulling