Spring 2002

1

Chp.2: Components of HCI

• How to achieve HCI goal of developing or improving systems (safety, utility, effectiveness, efficiency, usability, etc.) AND make sure system integrates well into organizational settings in which it’s used?

• A multi-disciplinary perspective is used -- analyze problems from different perspectives, including consideration of range of factors:

– organization (training, job design, politics)– environment (noise, lighting, ventilation)– health & safety (stress, headaches, fatigue)– human & comfort factors (motivation, enjoyment, satisfaction, proficiency)– user interface (input, output, color, graphics, etc.)– task factors (easy, complex, etc.)– constraints (cost, timescales, budgets, staff, equipment)– system functionality (hardware, software, application)– productivity factors (ouput levels, cost, production time)

Spring 2002

2

Chp.2: Components of HCI

• Four examples (3 from old text, 1 from new text):– airline ticket reservations– supermarket checkout– paper interface (should be PDA)– cell phones

• Each case considered in terms of a range of HCI factors:– human (e.g., staff, customer)– user interface– work activity– organization– comfort– productivity– etc…

Spring 2002

3

Chp.2: Components of HCI

• Airline reservation system• Before:

– customer went to travel agency– gave desired destination and travel times to agent– agent called airline– check with customer to see if times ok– if seats/time not ok, repeat…– ticket accounting: agents fills out paper forms,

sends to airlines bi-weekly

Spring 2002

4

Chp.2: Components of HCI

• Airline reservation system• Now:

– customer goes on-line– use types in desired times, destination– wait for search engine– like times, prices? if not repeat.– press buttons to give payment info– ticket accounting: issued electronically, airline dB

updated immediately

Spring 2002

5

Chp.2: Components of HCI

• Airline reservation system• HCI factors:

– human (staff): possibly out of work– human (customer): enjoys immediacy of seat selection, but

has to do more work him/her-self– UI: keyboard, web forms, etc.– work activity: more work placed on user– organization: training needs - user has to know, learn how

to use system; impersonal (some people prefer F2F interaction with travel agent)

– comfort: use has to have computer, may interfere with current task

– productivity: user has to take time away from other tasks

Spring 2002

6

Chp.2: Components of HCI

• Supermarket checkout• Goal: automate pricing/inventory procedures• Infrastructure requirements:

– all items in store must be barcoded– dB must exist to handle purchases/pricing– need scanning systems installed

Spring 2002

7

Chp.2: Components of HCI

• Supermarket checkout• Discussion:

– What are effects on:• user (staff)?• user (customer)?• is the user interface easy to learn/use?• how are problems handled (e.g., mis-scanned product,

incorrect price)?• what is the work activity - is training required? for whom?

(customer, staff, both?)• comfort: how is cashier affected?• system: what is needed (expensive? difficulty of install?)• productivity and “spin-off” factors: is process more

streamlined? What about marketing analysis (BiLo card)?

Spring 2002

8

Chp.2: Components of HCI

• Xerox Parc’s paper user interface (PalmPilot more appropriate)

• Discussion:– What are effects on:

• technology: what is required for development of PDA such as the PalmPilot (hardware, software)?

• what is the user-interface: easy to learn?• organization: is user’s “world” better organized?• comfort: easy to handle, transport?

Spring 2002

9

Chp.2: Components of HCI

• Cell phones (they’re great to pick on right now :)• Discussion:

– major usability drawbacks:• restricted access (getting better)• very small LCD screen• mostly text-based (image/video based starting to appear,

however, is this more expensive, i.e., pay for time to download?)

– assumptions used:• people want to use device while mobile• people want to interact with info while on the move• users will trade screen real estate for information (???)• phones will offer comparable interaction to PCs (???)

Spring 2002

10

Chp.2: Components of HCI

• In evaluating multiple factors, various disciplines contribute to HCI:– Computer Science (dB, O/S, AI, Grahpics, …)– Psychology (Cognitive, social, organizational)– IE (Ergonomics, human factors)– Design– Anthropology– Sociology– Philosophy– Linguistics

Spring 2002

11

Chp.2: Components of HCIComputer Science

• Mostly system/technology level– programming languages, compiler, etc.– O/S– Networking– WWW– GUI toolkits and window managers– multimedia– graphics– VR (new devices, incl. sensors, effectors, haptics)

• Application: use whatever devices/techniques suit the application

Spring 2002

12

Chp.2: Components of HCICognitive Psychology

• Understanding human behaviour, underlying mental processes, and capabilities and limitations thereof:– perception– attention– memory– learning– thinking– problem solving

• Application: apply principles to design, e.g., memory and attention are limited, don’t “clutter” UI with > 7 +/- 2 things at a time

Spring 2002

13

Chp.2: Components of HCISocial and Ogranizational Psychology

• Understanding human behaviour in social contexts:– individual’s influence on another– individual’s influence on group (e.g., leadership

qualities, or “weakest link”)– group’s influence on individual (e.g., peer

pressure)– relationship between different groups (e.g.,

different preferences, tastes, as in high school jocks, geeks, etc.)

• Application: consider how computers affect oranizations, groups of people…

Spring 2002

14

Chp.2: Components of HCIErgonomics & Human Factors

• Maximize operator’s safety, efficiency, reliability, performance, satisfaction, etc., e.g., ergonomic cockpits, office furniture, etc.

• Application: evaluate devices/interaction from ergonomic perspective, e.g.,:– “VDUs” (monitors) that minimize eye strain– devices that don’t cause carpel tunnel– VR simulators that promote training, test human

performance

Spring 2002

15

Chp.2: Components of HCILinguistics

• Study of language, understanding structure (syntax) and meaning (semantics)

• Application: apply to human-interface dialogue (how does system “speak” to user):– natural language interface (voice recognition, e.g.,

e.Digital’s MXP 100 MP3 player)– query languages (dB)– internationalization (locales)

Spring 2002

16

Chp.2: Components of HCIPhilosophy, Sociology, Anthropology

• “Soft science”?• Usually considers social implications of IT, e.g.,

– are workers being displaced?– are we becoming less social (more time in email than F2F)?– Increasingly important especially in domains such as

CSCW, I.e., how do people interact, communicate, collaborate

• Application: apply to computer-supported human-human interface dialogue (how do humans communicate):– eye-to-eye contact?– deictic (“look at that”) references?– e.g., Hiroshi Ishii’s TeamWorkstation: maintained eye

contact in video telephony applications

Spring 2002

17

Chp.2: Components of HCIConceptual Model of HCI

• HCI is neither the study of humans, nor of technology, rather it is the bridging between the two (to paraphrase Terry Winograd)

• Design concept: know how to make transition from what can be done technologically to how to make it usable for users in their environment

• Lowest level: select most appropriate input (VR, pen, mouse) and output device (video, speech, text), then decide on interaction style (natural language, GUI, VR, multimedia), knowing human psychology and particular human characteristics relevant to task at hand (e.g., for text display, don’t use green on red)

Spring 2002

18

Chp.2: Components of HCIConceptual Model of HCI

• To develop a conceptual model involves envisioning the proposed product, based on users’ needs and other identified requirements– one particularly useful HCI technique is to

develop prototypes• Key aspect: task-based analysis---what will users be

doing when carrying out their tasks?• Once interaction requirements have been defined:

– consider “look and feel” of interface– consider interface metaphor (e.g., desktop)– consider conceptual metaphor

Spring 2002

19

Chp.2: Components of HCIConceptual Models

• Conceptual models based on activities:– instructing (e.g., a system to do something; cmds)– conversing (e.g., with system; help page, menu)– manipulating and navigating (e.g., direct manip)– exploring and browsing

(not mutually exclusive)• Problems:

– instruction set: prone to (syntax) errors?– conversations: prone to semantic errors?– direct manipulation (click+drag): too literal?– exploring and browsing: how to allow navigation?

Spring 2002

20

Chp.2: Components of HCIConceptual Models

• Conceptual models based on objects:– spreadsheet (killer app based physical ledger)– Quicken (paper checks and registers

• Conceptual models may require a mix of models of objects and actions– but use caution: this may lead to numerous ways

of doing things, e.g.,• speak “delete file” (conversation?)• press CTRL-D (command)• drag file to trash (direct manipulation)

– this may result in steeper learning curve

Spring 2002

21

Chp.2: Components of HCIConceptual Models

• Interface metaphors:– another way of conceptualizing interface– can be based on actions, objects, or both– usually based on combination of familiar

knowledge with new concepts (using analogies to bridge gap between)

• Examples:– desktop metaphor (this one’s a popular example):

• dragging a file to trash (same as real action)• highlighting text

Spring 2002

22

Chp.2: Components of HCIConceptual Models• Interaction paradigms:

– a more general abstraction of conceptual model– a particular philosophy (prone to shifting :)– examples:

• applications for the desktop; GUI, WIMP• now moving “beyond the desktop”, e.g.,

– Body-Area Network (BAN)– ubiquitous computing (embedded tech.)– pervasive computing– wearable computing– AR / VR– tangible user interfaces– haptic interfaces– attentive environments (attentive displays)

Spring 2002

23

Chp.2: Components of HCIDesign process

• 4 components:– people– work (the task)– environment (physical, organizational, social)– technology

• The HCI design process: not quite as linear as software engineering’s “waterfall model”

• Key differences:– user-centered design: involve users as much as possible– integration of multidisciplinary knowledge– iterative design: periodically check with user

Spring 2002

24

Chp.2: Components of HCIDesign process

• Inolving users:– decide who end user is, how product will be used, made,

sold, marketed– observe current user practices - leads to system

requirements (how can current practice be improved?)– can use psychological models of human, e.g., follow & test

such concepts as Fitt’s Law– include user representatives on team:

• end users• management• marketing personnel• graphic designers, etc.

Spring 2002

25

Chp.2: Components of HCIDesign process

• Incorporating interdisciplinary knowledge:– computer science (AI, graphics, O/S, dB, etc.)– psychology– human factors– linguistics– philosophy– sociology– anthropology

Spring 2002

26

Chp.2: Components of HCIDesign process

• Iterate the design process:– use the Star model: featuring iterative evaluation

(as center of star)– components:

• requirements specification• task analysis / functional analysis• conceptual design / formal design• implementation• prototyping