Human-Computer Interaction — Dr. Amy Melniczuk

What is human-computer interaction (HCI), and which disciplines contribute to it?

Human-computer interaction is the field concerned with designing, evaluating, and improving the ways people interact with computers and other technologies.

HCI focuses on people's needs, abilities, goals, and experiences rather than only on the technical operation of a system.

HCI is interdisciplinary. For example, Carnegie Mellon's HCII identifies connections with: computer science, psychology and cognitive science, design, ergonomics, education and learning sciences, sociology, assistive technology, robotics and more.

What is the difference between a system being useful and being usable? Can you give an example of a system that is usable but not useful for a particular person or task?

A system is useful if it provides functions that help a person achieve a valuable goal.

A system is usable if people can use those functions easily, efficiently, and with few errors.

An e-scooter app is clearly designed, loads quickly, and is easy to navigate. It is usable. However, it is not useful for someone who lives in a city with no e-scooter stations or for a person who does not need e-scooter transportation.

Find an everyday interface that is confusing to use. What is the person trying to do, and which design decision causes difficulty? Suggest one improvement.

Microwave oven interfaces can be confusing (like the one in the dorms!)

The difficulty is that the microwave may have many similar-looking buttons, including: Number buttons, "Quick Start" buttons, Power-level buttons, Preset buttons such as "Popcorn" or "Reheat", separate "On/Off" and "Start" buttons.

The design decision causing difficulty is that the controls do not clearly show the correct sequence. A user may assume that pressing the number buttons directly enters the cooking time, when those buttons might instead start preset time intervals.

The display should immediately show a message such as "Cooking time: 2:30 — press Start" before the microwave begins. Grouping related controls, using larger labels, and providing confirmation would make the interface easier to understand and reduce errors.

What is a prototype, and how can testing one with users help a designer? What is one thing that asking "Do you like it?" would not tell you?

A prototype is an early version or model of a product. They allow designers to explore and improve ideas before building the final system.

How it can help:

• See whether users understand the layout and labels
• Discover where users become confused
• Identify missing features.
• Find errors before the product is fully developed
• Compare different possible designs

Asking "Do you like it?" would not tell the designer whether users can actually complete important tasks. A user might like the colors and appearance but still be unable to find the correct option. Task completion rate, time, errors, and requests for help provide more useful evidence of the product's usability.

Find one example of interaction beyond a keyboard and mouse, such as voice input or a tangible interface. Who might benefit, and how would you test whether it helps them?

Example: KIBO tangible robot

The KIBO robot is an example of tangible interaction. Instead of programming only through a keyboard and screen, children create programs by arranging physical wooden programming blocks. They can then scan the blocks and watch the robot move, make sounds, or respond to sensors.

KIBO can benefit:

• Young children who are still developing reading and typing skills.
• Children who learn better through physical movement and hands-on activities.
• Learners who have difficulty using a keyboard or navigating a programming interface.
• Children who benefit from reduced screen time.
• People with visual, hearing, physical, speech, cognitive, and neurological disabilities who may not use traditional interfaces

How would I test this?

• I would compare children using KIBO with children using a conventional screen-based programming activity.
• Give both groups the same programming task, such as making a robot move forward, turn, and make a sound.
• Measure how many children complete the task successfully.
• Record how long each child takes.
• Count errors and requests for help.
• Observe whether children understand the sequence of instructions.
• Ask children and teachers about enjoyment, confidence, and ease of use.

Sources used:

• hcii.cmu.edu — Research
• nngroup.com — Ten Usability Heuristics
• w3.org — Accessibility Fundamentals
• sites.bc.edu — KIBO Robot

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