2: Understanding and conceptualising interaction

Recap

• HCI has moved beyond designing interfaces for desktop machines

• Concerned with extending and supporting all manner of human activities

• Designing for user experiences, including: • Making work effective, efficient and safer• Improving and enhancing learning and training• Providing enjoyable and exciting entertainment• Enhancing communication and understanding• Supporting new forms of creativity and expression

Understanding the problem space

• What do you want to create?

• What are your assumptions?

• What are your claims?

• Will it achieve what you hope it will? If so, how?

A framework for analysing the problem space

• Are there problems with an existing product or user experience?

• Why do you think there are problems?• How do you think your proposed design ideas might overcome these?

• When designing for a new user experience how will the proposed design extend or change current ways of doing things?

An example

• What do you think were the main assumptions made by developers of online photo sharing and management applications, like Flickr?

Assumptions and claims

• Assumptions• Able to capitalise on the hugely successful phenomenon of blogging

• Just as people like to blog so will they want to share their photo collections with the rest of the world... and get comments back

• A claim • From Flickr’s website (2005): “almost certainly the best online photo management and sharing application in the world”

From problem space to design space

• Having a good understanding of the problem space can help inform the design space• e.g., what kind of interface, behavior, functionality to provide

• But before deciding upon these it is important to develop a conceptual model

Conceptual model

• Need to first think about how the system will appear to users (i.e. how they will understand it)

• A conceptual model is: – “a high-level description of how a system is organized and operates.” (Johnson and Henderson, 2002, p. 26)

What is and why do we need a conceptual model?

• Not a description of the user interface but a structure outlining the concepts and the relationships between them

• Why not start with the nuts and bolts of design?• Architects and interior designers would not think about which colour curtains to have before deciding where the windows will be placed in a new building

• Enables “designers to straighten out their thinking before they start laying out their widgets” (p. 28)

• Provides a working strategy and a framework of general concepts and their interrelations

A classic conceptual model: the spreadsheet

• Analogous to ledger sheet

• Interactive and computational

• Easy to understand

• Greatly extending what accountants and others could do

www.bricklin.com/history/refcards.htm

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Why was it so good?

• It was simple, clear, and obvious to the users how to use the application and what it could do

• “it is just a tool to allow others to work out their ideas and reduce the tedium of repeating the same calculations.”

• It capitalised on users’ familiarity with ledger sheets

• Got the computer to perform a range of different calculations and recalculations in response to user input

Another classic

• 8010 Xerox Star office system targeted at workers not interested in computing per se

• Spent several person-years at beginning working out the conceptual model

• Simplified the electronic world, making it seem more familiar, less alien, and easier to learn

Johnson et al (1989)

The Star interface

Helps the design team

• Orient themselves towards asking questions about how the conceptual model will be understood by users

• Not to become narrowly focused early on • Establish a set of common terms they all understand and agree upon

• Reduce the chance of misunderstandings and confusion arising later on

Main components

• Major metaphors and analogies that are used to convey how to understand what a product is for and how to use it for an activity.

• Concepts that users are exposed to through the product

• The relationships between the concepts• e.g., one object contains another

• The mappings between the concepts and the user experience the product is designed to support

Interface metaphors

• Designed to be similar to a physical entity but also has own properties

• e.g. desktop metaphor, search engine• Exploit user’s familiar knowledge, helping them to understand ‘the unfamiliar’

• People find it easier to learn and talk about what they are doing at the computer interface in terms familiar to them

• Conjures up the essence of the unfamiliar activity, as a starting point to understanding new aspects of the unfamiliar functionality

Benefits of interface metaphors

• Makes learning new systems easier

• Helps users understand the underlying conceptual model

• Can be innovative and enable the realm of computers and their applications to be made more accessible to a greater diversity of users

Problems with interface metaphors (Nelson, 1990)

• May break conventional and cultural rules

• e.g., recycle bin placed on desktop

• Can constrain designers in the way they conceptualise a problem space

• May conflict with design principles

• May force users to only understand the system in terms of the metaphor, rather than how it really works

• Designers can inadvertently use bad existing designs and transfer the bad parts over

• Limits designers’ imagination in coming up with new conceptual models

Interaction types

• Instructing

• issuing commands using keyboard and function keys and selecting options via menus

• Conversing

• interacting with the system as if having a conversation

• Manipulating

• interacting with objects in a virtual or physical space by manipulating them

• Exploring

• moving through a virtual environment or a physical space

Instructing• Where users instruct a system by telling it what to do• e.g., tell the time, print a file, find a photo, list files matching a regular expression

• Very common interaction type underlying a range of devices and systems

• A main benefit of instructing is to support quick and efficient interaction• good for repetitive kinds of actions performed on multiple objects

Vending machines

Describe the conceptual model underlying the two vending machines

Which is easiest to use?

Conversing

• Like having a conversation with another human

• Differs from instructing in that it is more like two-way communication, with the system acting like a partner rather than a machine that obeys orders

• Ranges from simple voice recognition menu-driven systems to more complex ‘natural language’dialogues

• Examples include search engines (ask.com), advice-giving systems and help systems

Pros and cons of conversational model

• Allows users, especially novices and technophobes, to interact with the system in a way that is familiar

• makes them feel comfortable, at ease and less scared

• Misunderstandings can arise when the system does not know how to handle what the user says

• e.g. child types “How many legs does a centipede have?” into a search engine that uses natural language. The system responds:

Manipulating

• Exploits users’ knowledge of how they move and manipulate in everyday non-digital objects

• Virtual objects can be manipulated by moving, selecting and arranging them

• Tracked physical objects (e.g., bricks, blocks) that are manipulated in one physical medium (e.g., placed on a table) can result in other events in another medium (e.g., projected image on the table)

Urp

See videos at http://tangible.media.mit.edu/projects/luminousroom/

Manipulatives (PicoCrickets)

Direct manipulation

• Shneiderman (1983) coined the term Direct Manipulation

• Came from his fascination with computer games at the time

• Proposes that digital objects be designed so they can be interacted with in a way analogous to how everyday non-digital objects are manipulated

• Assumes that direct manipulation interfaces enable users to feel that they are directly controlling the digital objects

• Main example: desktop icons, windows, menus...

Core principles of DM

• Continuous representation of objects and actions of interest

• Physical actions (e.g. mouse movement, button pressing) instead of issuing commands with complex syntax

• Rapid reversible actions with immediate feedback about object of interest

Why are DM interfaces so enjoyable?

• Novices can learn the basic functionality quickly

• Experienced users can work extremely rapidly to carry out a wide range of tasks, even defining new functions

• Intermittent users can retain operational concepts over time

• Error messages rarely needed

• Users can immediately see if their actions are furthering their goals and if not do something else

• Users experience less anxiety

• Users gain confidence and mastery, and feel in control

What are the disadvantages of DM?

• Some people take the metaphor of direct manipulation too literally

• Not all tasks can be described by objects and not all actions can be done directly

• Some tasks are better achieved through instruction (e.g. list files matching regexp) or delegation to non-interactive process (e.g., spell checking), rather than manipulating

• Moving a mouse around the screen can be slower than pressing function keys to do same actions

Exploring

• Involves users moving through virtual or physical environments

• Examples include:• 3D desktop virtual worlds where people navigate using mouse around different parts to socialise (e.g., Second Life)

• CAVEs where users navigate by moving whole body, arms and head

• context aware environments, embedded with sensors, that present digital information to users at appropriate places and times

A virtual world

A CAVE (see figures 2.12 & 2.13)

Theories, models and frameworks

• Are used to inform and inspire design

• A theory is a well-substantiated explanation of some aspect of a phenomenon

• A model is a simplification of some aspect of human–computer interaction intended to make it easier for designers to predict and evaluate alternative designs

• A framework is a set of interrelated concepts and/or a set of specific questions

Main differences

• Theories tend to be comprehensive, used to explain or predict human–computer interactions

• Models tend to be practical/usable simplifications of some aspect of human–computer interaction

• Frameworks tend to be prescriptive, providing designers with concepts, questions and principles to consider

Summary points

• Need to have a good understanding of the problem space

• specifying what it is you are doing, why, and how it will support users in the way intended

• A conceptual model is a high-level description of a system

• what users can do with it, and the concepts they need to understand how to interact with it

• Decisions about conceptual design should be made before commencing any physical/program design

• Interface metaphors are commonly used as part of a conceptual model

Summary points

• Interaction types (e.g., conversing, instructing) provide a way of thinking about how best to support the activities users will be doing when using a product or service

• Theories, models, and frameworks provide other ways of framing and informing design and research