chapter 3 understanding users. outline what is cognition? cognitive frameworks

Chapter 3

Understanding users

Outline

What is cognition?

Cognitive frameworks

Why do we need to understand users?

Interacting with technology is cognitive

We need to take into account cognitive processes involved and cognitive limitations of users

We can provide knowledge about what users can and cannot be expected to do

From: www.id-book.com

Why do we need to understand users?

Identify and explain the nature and causes of problems users encounter

Supply theories, modelling tools, guidance and methods that can lead to the design of better interactive products


What is cognition? (การร�บร��) What goes on in our heads when we carry

out our everyday activities

Cognitive processes: thinking, remembering, learning, daydreaming, decision-making, seeing, reading, writing, and talking

Kinds of cognition

Norman (1993) 1) Experiential cognition

a state of mind in which we perceive, act, and react to events around us effectively and effortlessly

requires reaching a certain level of expertise and engagement

Examples: driving a car, reading a book

Kinds of cognition

Norman (1993) 2) Reflective cognition

involves thinking, comparing, and decision-making leads to new ideas and creativity

Examples: designing, learning, and writing a book

Specific kinds of processes

Attention* Perception and recognition* Memory* Learning Reading, speaking, and listening Problem-solving, planning, reasoning,

decision-making

Attention

It is the process of selecting things to concentrate on, at a point in time, from the range of possibilities available

Involves auditory and/or visual senses ex. Auditory – waiting in the dentist’s waiting room

Visual - scanning the football results

Attention

Whether this process is easy or difficult depends on 1) clear goals

ex. clear goals – finding out World Cup results of your favorite football team

ex. unclear goals – not sure what to eat 2) information is salient in the environment

Attention

Whether this process is easy or difficult depends on 1) clear goals 2) information is salient in the environment

information presentation: the way information is displayed can also greatly influence how easy or difficult it is to attend to appropriate pieces of information

Attention

Attention enables us to focus on relevant information

But

This means we can’t keep track of all information

Attention

Information at the interface should be presented to attract users’ attention, e.g. use color, sound and flashing lights

Activity

Tullis (1987) found that the two screens produced quite different results 1st screen - took an average of 5.5 seconds to

search 2nd screen - took 3.2 seconds to search

Why, since both displays have the same density of information?


Activity

Spacing In the 1st screen the information is bunched up

together, making it hard to search In the 2nd screen the characters are grouped into

vertical categories of information making it easier


Design implications for attention

Make information salient when it needs attending to

Use several techniques to achieve this ex. animated graphics, color, underlining, spacing

of items Avoid cluttering the interface with too much

information, ex. google.com

Perception and recognition

how information is acquired from the environment and transformed into experiences

it is complex, involving other cognitive processes, e.g. memory, attention, and language

it is important to present information in a way that can be readily perceived in the manner intended

Activity

Weller (2004) found people took less time to locate items for information that was grouped using a border (2nd screen) compared with using

color contrast (1st screen) Some argue that too much white space on

web pages is detrimental to search Makes it hard to find information

Do you agree?


Perception and recognition

Information needs to be represented in an appropriate form to facilitate the perception and recognition of its underlying meaning

Example: lip-synch applications

Design implications for perception

Information is represented to be perceptible and recognizable across different media

Icons and other graphical representations’ meaning should be obvious to users

Bordering and spacing are effective visual ways of grouping information, making it easier to perceive and locate items


Sounds should be audible and distinguishable

Speech output should be clear so that users can understand their meaning


Text should be legible and distinguishable from the background

Tactile feedback should allow users to recognize meaning of various touch sensations

Memory

Involves encoding and retrieving (recall) various kinds of knowledge

We can’t remember everything

Filtering process

Memory

The more attention paid to something and the more it is processed in terms of thinking about it and comparing it with other knowledge, the more likely it is to be remembered

The context in which the information is encoded Example: seeing your neighbors on a train

instead of in the hallway of your apartment

Memory

People are better at recognizing than recalling Example: people are very good at recognizing

thousands of pictures even if they have seen them briefly before

Memory

People are good at remembering visual cues about things Examples:

color of items location of objects marks on objects

People find it more difficult to learn and remember arbitrary material, e.g., birthdays, phone numbers

Recognizing easier than recalling

GUIs provide visually-based options vs. command-based systems

Displaying lists of visited URLs

Design implications for memory

Don’t overload users’ memories with complicated procedures for carrying out tasks

Design interfaces that promote recognition rather than recall

Provide users with a variety of ways of encoding digital information to help them remember where they have stored them e.g., categories, color, flagging, time stamping

Learning

2 interpretations: 1) how to use a computer-based application

2) using a computer-based application to understand a given topic

Learning

1) how to use a computer-based application

Jack Carroll (1990) Users prefer to ‘learn through doing’ GUIs and direct manipulation interfaces

Support exploratory interaction Allow users to ‘undo’ their actions

Learning

Jack Carroll

“training-wheels’ approach Restrict possible functions to the basics for a novice Extend these as the novice becomes more experienced Rationale: make initial learning more tractable -> help

learner focus on simple operations before moving on to more complex ones

Learning

2) using a computer-based application to understand a given topic Use interactive technologies, e.g. web-based,

multimedia, virtual reality Help users to better understand abstract

representations of the materials Make a connection between abstract

representations, e.g. diagrams, text, etc., and concrete representations through interactive technologies

Design implications for learning

Design interfaces that encourage exploration Design interfaces that constrain and guide

users to select appropriate actions when initially learning

Dynamically link concrete representations and abstract concepts to facilitate learning of complex materials

Reading, speaking, listening

Differences Written language is permanent (i.e., enables

rereading); listening is transient

Reading (i.e. via scanning) can be quicker than speaking or listening

Listening requires less cognitive effort than reading or speaking

Reading, speaking, listening

Differences Written language tends to be grammatical;

spoken language is often ungrammatical

People’s ability to use language is markedly different

People with hearing and sight problems are restricted in the way they can process language

Design implications for reading, speaking, listening

The length of speech-based menus and instructions should be at a minimum

Accentuate the intonation of artificially generated speech voices

Provide alternatives to make text large on a screen, without affecting the formatting, for people who find it hard to read small text

Problem-solving, planning, reasoning, decision-making

All of these processes involve reflective cognition

thinking about what to do, what the options are, and what consequences of actions might be

The extent to which people engage in reflective cognition depends on their level of experience with a domain, application, or skill

Design implications

Provide additional information to help users learn more about how to carry out an activity more effectively, e.g. web searching

Use simple and memorable functions for applications supporting rapid decision making and planning on the move

Cognitive frameworks

Are conceptual frameworks that explain and predict user behavior based on theories of cognition

Influential ones are: Mental models Theory of action Information processing External cognition Distributed cognition

Mental models

Users develop an understanding of a system through learning and using it

A user’s mental model Knowledge of how to interact with a system How that system works

Mental models

Used by people to reason about the system and to figure out what to do when something unexpected happens or when encountering unfamiliar systems

Craik (1943) described mental models as internal constructions of some aspect of the external world, enabling predictions and inferences to be made

Mental models

Involves unconscious and conscious processes, where images and analogies are activated

Deep versus shallow models (e.g. how to drive a car and how it works)

Everyday reasoning and mental models

(a) You arrive home on a cold winter’s night to a cold house. How do you get the house to warm up as quickly as possible? Set the thermostat to be at its highest or to the desired temperature?

(b) You arrive home starving hungry. You look in the fridge and find all that is left is an uncooked pizza. You have an electric oven. Do you warm it up to 375 degrees first and then put it in (as specified by the instructions) or turn the oven up higher to try to warm it up quicker?


Heating up a room or oven that is thermostat-controlled

Many people have erroneous mental models (Kempton, 1996)

Why? General valve theory, where ‘more is more’

principle is generalised to different settings (e.g. gas pedal, gas cooker, tap, radio volume)

Thermostats based on model of on-off switch model


Heating up a room or oven that is thermostat-controlled

Same is often true for understanding how interactive devices and computers work: Poor, often incomplete, easily confusable, based

on inappropriate analogies and superstition (Norman, 1983)

e.g. elevators and pedestrian crossings - lot of people hit the button at least twice

Why? Think it will make the lights change faster or ensure the elevator arrives!


Transparency

To help users develop better mental models, the interactive systems could be designed to be more transparent

Transparency involves: Useful feedback in response to user input Easy-to-understand and intuitive ways of

interacting

Transparency

Also provide the right kind and level of information Clear and easy-to-follow instructions Appropriate online help and tutorials Context-sensitive guidance for users, set at their

level of experience, explaining how to proceed when they are not sure what to do at a given stage of a task

Theory of action

Another way to conceptualize user-system interaction is in terms of users’ goals and what they need to do to achieve them

Theory of action (Norman, 1986)

specifies seven stages of an activity

Establish a goal Form an intention Specify an action sequence Execute an action Perceive the system state Interpret the state Evaluate the system state with respect to goals and

intentions

An example: reading breaking news on the web(i) Set goal to find out about breaking news

decide on news website(ii) Form an intention

check out BBC website(iii) Specify what to do

move cursor to link on browser(iv) Execute action sequence

click on mouse button (v) Check what happens at the interface

see a new page pop up on the screen (vi) Interpret it

read that it is the BBC website(vii) Evaluate it with respect to the goal

read breaking news


In reality

Human activity does not proceed in such an orderly and sequential manner

More often the case that stages are missed, repeated or out of order

Users do not always have a clear goal in mind but react to the world, e.g. what appears on the screen

Theory of action

Theory is only approximation of what happens and is greatly simplified

Help designers think about how to help users monitor their actions in relation to their goals

Theory of action

Generally, the theory suggests the importance of providing feedback about the system state so that they can check whether their goals and intentions have been met

Examples: Dialog boxes – remind users of possible

intentions Menus – allow users to browse, scan, and point at

possible options

Gulf of execution

Difference between the intentions of the users and what the system allows them to do or how well the system supports those actions (Norman, 1988)

Gulf of evaluation

Degree to which the system/artifact provide representations that can be directly perceived and interpreted in terms of the expectations and intentions of the user (Norman, 1988)

“The gulf is small when the system provides information about its state in a form that is easy to get, is easy to interpret, and matches the way the person thinks of the system” (Norman, 1988)

Information processing


Based on modeling mental activities that happen exclusively inside the head

However, most cognitive activities involve people interacting with external kinds of representations such as books, documents, and computers

External cognition & Distributed cognition

Study cognitive activities in the context in which they occur

Study how structures in the environment can both aid human cognition and reduce cognitive load

External cognition

Concerned with explaining the cognitive processes involved when we interact with different external representations

Explain cognitive benefits of using different representations Externalizing to reduce memory load Computational offloading Annotating and cognitive tracing

Externalizing to reduce memory load

Diaries, reminders, calendars, notes, shopping lists, to-do lists - written to remind us of what to do

Post-its, piles, marked emails - where place indicates priority of what to do

External representations: Remind us that we need to do something (e.g. to buy

something for mother’s day) Remind us of what to do (e.g. buy a card) Remind us when to do something (e.g. send a card by a

certain date)

Computational offloading

When a tool is used in conjunction with an external representation to carry out a computation

Example: using pen and paper to solve a math problem

The kind of representation and tool used can change the nature of the task to being more or less easy


Try doing the two sums below (a) in your head, (b) on a piece of paper and c) with a calculator. 234 x 456 =?? CCXXXIIII x CCCCXXXXXVI = ???

Which is easiest and why? Both are identical sums


The kind of representation can transform a task into one that is easy or one that is difficult Ex. Arabic numbers vs. roman numbers

The kind of tool used also can change the nature of the task to being more or less easy Ex. Pen and paper vs. calculator

Annotating and cognitive tracing

Annotating involves modifying external representations through making marks Ex. Crossing off or underlining items

Cognitive tracing involves externally manipulating items into different orders or structures Ex. Creating different document piles to reflect the

change of what needs to be done, playing cards

Design implications based on external cognition

Provide external representations at an interface that reduce memory load and facilitate computational offloading Ex. Information visualizations, Ex. GUI – wizards, dialog boxes guiding users

through interactions

Distributed cognition

Studies the nature of cognitive phenomena across individuals, artifacts, and internal and external representations

Describes a ‘cognitive system’, which entails interactions among people, the artifacts they use, and the environment they are working in


Example: Cognitive system: an airline cockpit

Interactions among people: pilot, co-pilot, air traffic controller

Interactions with artifacts: pilot, co-pilot, instruments in the cockpit

Interactions with the environment: pilot, co-pilot, runway, sky


Describes these interactions in terms of how information is represented and re-represented as it moves across individuals and through different artifacts

These transformations of information are referred to as changed in representational state

Distributed Cognition vs. Information processing


Focuses on what is happening inside the head of an individual


Focuses on what is happening across a system of individuals and artifacts

Distributed cognition analysis

The distributed problem-solving that takes place

The role of verbal and non-verbal behavior The various coordinating mechanisms that

are used (e.g., rules, procedures) The communication that takes place as the

collaborative activity progresses How knowledge is shared and accessed

Key points

Cognition involves several processes including attention, memory, perception and learning

The way an interface is designed can greatly affect how well users can perceive, attend, learn and remember how to do their tasks

Theoretical frameworks such as mental models and external cognition provide ways of understanding how and why people interact with products, which can lead to thinking about how to design better products


chapter 3 understanding users. outline what is cognition? cognitive frameworks

Documents

attention information

decisionmaking slide

attention attention

environment slide

book slide

users attention

information salient

way information