15  Lecture 1: Introduction to Human-Computer Interaction

15.1 Intro

Today, interaction with intelligent systems is continous. We engage with technology through:

  • Mobile & Web: Smartphones and web applications
  • Physical Systems: Automated machines and embedded systems
  • Ubiquitous Tech: Wearable devices and samrt environments

Two primary fields work to improve how we use technology:

  1. Human-Computer Interaction (HCI): Understanding and improving the relationship between humans and computers.
  2. Interaction Design (ID): Designing interactive systems that are usable, useful, and provide a positive user experience

HCI is an interdisciplinary field that ‘does’ interaction design.

Other definitions for interaction design are:

  • Designing interactive products to support people in their everyday and working lives
  • The design of spaces for human communication and interaction

Examples of interactive systems are:

  • Consumer Electronics: devices such as smartphones, tablets, smart watches, and other wearables are designed to support personalized experiences
  • Public Terminal: Systems like ATMs, self-service kiosks, ticketing machines, and vending machines.
  • Digital Platforms: websites, web applications and social media.
  • Critical Systems: Medical devices, industrial control panels, aviation systems, and other safety-critical technologies

The goals of interaction design are

  • Develop usable products
    • Usability means easy to learn or easy to use
  • Provide an enjoyable experience
  • Involves users in the design process

There are 3 pillars to interaction design

  • User: Who is using the system? (Who)
  • Activity: What is the user trying to accomplish? (What)
  • Context: Where and under what conditions is the interaction taking place? (Where)

When designing, you need to take into account the three pillars. You also need to optimize the interactions users have with a product. Some techniques to understand the user needs are

  • Observing users in real environments
  • Conducting interviews and surveys
  • Involving users in usability testing
  • Applying established user-centered design methods

The following table demonstrates 3 examples of design flows:

Example of Design Flaws
Design Flaw Human Impact Technical Result
Activation Barrier Increase Cognitive Load Slower Transaction Times
Broken Convention High Error Rate User Frustration / Abandonment
Hidden Affordances Conusion Underutilization of Features

An important concept here is interfaces. An interface serves as a point of interaction between a user and a computer system. They include

  • Input Mechanisms
  • Output Mechanisms
  • Interaction Styles

There is an increasing number of interactive design consultations including

  • Nielsen Norman Group: help companies enter the age of the consumer, designing human-centered products and services
  • Swim: provides a wide range of design services, in each case targeted to address the product development needs at hand
  • IDEO: creates products, services and environments for companies pioneering new ways to provide value to their customers

15.2 Professionals in the ID business

  • interaction designers- people involved in the design of all the interactive aspects of a product
  • usability engineers- people who focus on evaluating products, using usability methods and principles
  • web designers- people who develop and create the visual design of websites, such as layouts
  • information architects- people who come up with ideas of how to plan and structure interactive products
  • user experience designers- people who do all the above but who may also carry out field studies to inform the design of products

15.3 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.

15.3.1 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.

15.3.2 What activities are performed?

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

15.3.3 What Activities are Performed?

Designers should analyze all of the following for the interaction

  • Location and Environment
  • Environmental Factors
  • Physical Constraints

15.4 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.

15.4.1 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.

15.4.2 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.

15.4.3 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.

15.4.4 Phase 4: Evaluate Design Continuously

Here, you refine the design through user feedback.

15.5 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

15.6 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
Goal Type Primary Focus Key Question
Usability Practical & Functional “Can the user do it?”
User Experience Emotional & Psychological “How does the user feel?”

15.7 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

15.8 Usability Principles

They are similar to design principles, except more prescriptive. They are used mainly as the basis for evaluating systems a provide a framework for heuristic evaluation.

  • Visibility of system status
  • Match between system and the real world
  • User control and freedom
  • Consistency and standards
  • Help users recognize, diagnose and recover from errors
  • Error prevention
  • Recognition rather than recall
  • Flexibility and efficiency of use
  • Aesthetic and minimalist design
  • Help and documentation