Man and Machine:Introduction to HCI (MMI)

Contents

HCI: Introduction

Design Rules:– Guidelines– Principles– Theories

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What is HCI ?

Human–computer interaction (HCI) or Man-Machine Interaction (MMI) is the study of interaction between people (users) and computers.

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HCI

Human-computer interaction (HCI) is:

“concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them” (ACM SIGCHI, 1992, p.6)

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Goal of HCI

Is to enhance the interaction between humans and computer systems

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Usability = Quality

Errors

Satisfaction Learnability

Efficiency

Memorability

Usability

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Good UIs on Successful Products

Palm succeeded where other handhelds had failed due to a focus on usability

Apple iPod / Apple iPhone

Apple iPad

Wii controller, vs. XBox, PS3graphics & power

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Bad UIs can SinkProducts & Companies

Ford dropped in ratings due to touch screen interface– “Despite Ford’s improvements in manufacturing quality, their

overall ratings fell precipitously this year due solely to the poor software interaction on their dashboards.” – NYT, Cooper Report

– “’annoying’ behavior oftheir driver-facinginteractive systemsthat caused theirratings to plummet.”

Brad Myers (Human Computer Institute)8

Bad UIs Can Cause Disasters

Aegis– July 4, 1988; Iranian Airbus shootdown by the Vincenneshttp://www.washingtonpost.com/wp-srv/inatl/longterm/flight801/stories/july88crash.htm

http://en.wikipedia.org/wiki/USS_Vincennes_%28CG-49%29

Deaths in kids: http://pediatrics.aappublications.org/cgi/content/abstract/116/6/1506

– “Unexpected Increased Mortality After Implementation of a Commercially Sold Computerized Physician Order Entry (CPOE) System”

Because it took so much longer, did not reduce errors overall

Florida ballots (2000) http://www.asktog.com/columns/042ButterflyBallot.html

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Florida Ballots in 2000

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A measure of usability ….

Return on investment in the range of 3:1 to 100:1 11

Design Rules: Guidelines, Principles & Theories

Design Rules

Design rules are rules a designer can follow in order to increase the usability of the eventual software product. These rules can be classified based on authority and generality where:– Authority: whether rule must be followed or is merely a

suggestion– Generality: whether rule is applicable to many or

limited applications(Dix

et al., 2004)

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Guidelines are a basis for determining a course of action:

•low in authority and general in application•Less abstract than principles•More technology oriented

Principles are abstract design rules:•High generality and low authority•Derived from psychology, computing and sociology•Require deeper understanding of human element in interaction•Largely independent of technology

Design Rules

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Guidelines

Develop a shared language Promote consistency Record best practices We will look at 4 sample guidelines

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Navigating the interface

Sample of the National Cancer Institute’s guidelines:– Standardise task sequences– Ensure that embedded links are descriptive– Use unique and descriptive headings– Use check boxes for binary choices– Develop pages that will print properly– Use thumbnail images to preview larger images

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Organising the display

Smith and Mosier (1986) offer five high-level goals– Consistency of data display– Efficient information assimilation by the user– Minimal memory load on the user– Compatibility of data display with data entry– Flexibility for user control of data display

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Facilitating data entry

Smith and Mosier (1986) offer five high-level objectives as part of their guidelines for data entry– Consistency of data-entry transactions– Minimal input actions by user– Minimal memory load on users– Compatibility of data entry with data display– Flexibility for user control of data entry

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Android Development User Interface Guidelines

Icon design

Widget design

Activity & Task design

Menu design19

Use a wide variety of iconsTechnical specs, with templates provided.

Use a wide variety of iconsTechnical specs, with templates provided.

Describes how widgets fit together with graphics templates.

Describes how widgets fit together with graphics templates.

Describes navigation, multitasking, activity re-use, intents, and the activity stack.

Describes navigation, multitasking, activity re-use, intents, and the activity stack.

Describes how to arrange menu items, when to put commands on-screen, and other details about menu design.

Describes how to arrange menu items, when to put commands on-screen, and other details about menu design.

Apple’s Human Interface Principles

Aesthetic integrity

Consistency

Direct manipulation

Metaphors

User control

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