Assignment 500 words

HUMAN ACTION CYCLE &

INTERACTION STYLES

INTRODUCTION

§ To create a physical UI design:

§ You need to understand how users interact with computer systems

§ Ch10 discusse the human action cycle (HAC) § A model of the interaction process

§ Builds on the concept of Tasks, Actions, and Goals

§ In Ch11, we will look at the different interaction styles available to designers for facilitating communication between a user & a system

HUMAN ACTION CYCLE § Users are goal oriented

§ They have something particular they want to achieve by using a computer system

§ Human action cycle § A psychological model that describes the steps users take when they interact with

computer systems § The cycle shows the way users perform actions and tasks to achieve their goals.

§ HAC captures iterative cognitive and physical process in four stages: § Goal formation § Execution stage § Interaction § Evaluation stage

HUMAN-ACTION-CYCLE § Prezi Animation

§ Canvas > Modules > Human Action Cycle

DIFFERENT INTERACTION STYLES § Different ways of interacting

with systems § Command-line § Menu selection § Form-fill § Direct manipulation § Anthropomorphic

COMMAND-LINE § Powerful – access to system

functionality § Flexible – options and

parameters § Limitations

§ Commands must be remembered § Commands are obscure and

cryptic § Better for experts to use § Error rates are high

MENU SELECTION § A set of options from which

the user must choose § Offer cues for user

recognition § Breaks the complex into small

steps

§ Guidelines: § Use task semantics to organize

menus § Give menu items titles that

match their function § Avoid lengthy menus § Use short names § Provide short cuts

FORM-FILL § Used when information needs to

be gathered from a user

§ Users work through form, entering appropriate values

§ May jump between fields

§ From is a metaphor for papers forms

The form on the screen is a metaphor for a paper form. A well-designed form-fill interface should help the user to construct an accurate mental model quickly, as most users are familiar with completing forms. This should make using such computer- based forms relatively straightforward.

Box 11.3 provides some guidelines for designing form-fill interfaces.

2. Interaction Styles

211 Part 3

Figure 11.2 Form-fill on the Australian Broadcasting Authority’s web site. (Retrieved May 15, 2004.)

There is more information on designing usable forms at www. formsthatwork. com.

GUIDELINES § Give meaningful titles or

labels to fields § Give familiar field labels (use

users’ language) § Provide comprehensible

instructions § Incorporate logical grouping and

sequencing § Use consistent terminology and

abbreviations

§ Provide white space and boundaries

§ Restrict the characters that can be entered

§ Provide default values where applicable

§ Provide error correction § Provide error messages for

unacceptable values § Indicate required fields § Recognition over recall

DIRECT MANIPULATION

§ Users interact directly with UI objects § Most modern interfaces use

direct manipulation

§ Visible and continuous representation of task objects

§ Little syntax to remember § Object manipulated by physical

actions § Operations are rapid; effects

immediately visible § Users feel that they are

interacting with the domain rather than an interface

§ Novices learn quickly

ANTHROPOMORPHIC § Interaction that mimics how

we interact with each other § Voice command § Visual § Touch

USER CHARACTERISTICS § Aspects of user characteristics that influence the choice of

interaction style

User’s Characteristics CL Menu FF DM Anth

Novice √ √ √ Modest knowledge of task domain with some computer skills

√ √ √ √

Occasional user, knowledgeable √ √ √ √ √

Frequent user √ √ √

TASK CHARACTERISTICS AND STYLE § Aspects of the task domain that influence the selection of

interaction style Task Characteristics CL Menu FF DM Anth Large amount of data entry √ √

Paper form replacement √

Familiar notation exists √

Natural visual representation exists √

Multiple decisions or selections from large range of unfamiliar options

√

Exploration is anticipated √