Human Computer Interaction Flashcards
Fundamentally what is HCI?
- study, planning and design of interaction between people and computers
- how interactions evolve as people evolve
- community of communities (multidisciplinary)
- bigger than CS itself
- manages innovation to ensure human values and priorities are advanced and not diminished through new tech
How does HCI link with cognitive science?
- HCI is one of first examples of cognitive engineering
- cognitive science presented people, concepts, skills and a vision for addressing HCI needs through merge of sci and engineering
How does HCI link with usability and accessibility?
- Usability is open ended concept and can never be reduced to a fixed checklist
- usability is the original focus of HCI
- easy to learn, easy to use
- usability evolved to now associate with qualities such as fun, wellbeing, collective efficient and many more
- design of interfaces that allow people to do work without frustration
- understanding of what people are comfortable with
- systems need to be available to people regardless of disability circumstance, background etc
What is conceptual framework?
Designers model (model of how system SHOULD work) -> System image (how the system ACTUALLY works as portrayed through interface, manuals etc) -> user model (how the user understands the system) -does the user model match the design model?
What is social computing?
- computing used to communication, computer is not used to communicate it is used to host the communication platform
- Social media = used for communication + news + entertainment, expected user is everyone, no training required
- online shopping - used for shopping, used by people who may be disabled and cant go shopping or who live far away from shops, or ease of use
What is the messy desk metaphor?
- files and folders displayed as icons that could be scattered around the display surface
- eventually replaced with search due to clutter
How has HCI changed over the years?
- moving from expert systems to widely available tech
- closing gap between designer and user
- everyone in the world became a potential comp user in the early 80’s, not just IT profs and hobbyists
- pervasive in daily lives, necessary to participate in society
- way forward for computing entailed understanding and better empowering users
3 ways HCI has moved beyond the traditional desktop over time?
- social computing
- search feature
- continual diversification in ecology of computing devices
What challenges are emerging as HCI develops?
-who needs to use the device/software and what are the consequences if they cant?
What are some developments in HCI?
- increasingly sophisticated documentation considering human theories and testing
- software engineering began focusing on non-fundamental requirements, including usability and maintainability and empirical dev processes
- development in computer graphics began to recognise that interactive systems were the key to progressing
How did human abilities/features influence the development of HCI?
- need to design equipment and devices that fit the human body and cognitive abilities (pioneered by NASA and IBM)
- need to optimise human well-being and performance
- need to consider humans cognitive limitations (attention, memory, workload)
Why is user experience important?
- user needs to be put at centre of everything
- requirements, prototyping, development and evaluation all need to include user input
- dialogue is key - constant constructive talk between dev and end user
What is the task artefact cycle?
- simple terms = I have a task, I develop an artefact, this artefact opens new possibilities for new tasks etc etc
- Human activities have needs, preferences and design visions, artefacts are designed in response
- through course of artefact adoption and appropriations, new designs provide new possibilities for action and interaction
- the activities articulate further human needs, preferences and design visions
How has HCI developed in a design sense?
- used to be a design science or was thought of as pursuing guidance for designers
- HCI research and design were separate contributing areas of professional expertise
- from 90’s it assimilated and eventually spawned a series of design communities
What were original HCI theories?
-things such as GOMS (goals, operations, methods, selection rules) which were employed to model the cognition and behaviour of individuals interacting with simple displays, keyboards and pointing devices
What are more recent HCI theories?
- perceptual theories that explain how objects are recognised in a graphical display
- mental model theories appropriated to explain the role of concepts in shaping interactions
- active user theories explain how and why users learn and making sense of interactions
What are the 3 eras of theories?
- those that view HCI as information processing
- those that view interaction as initiative of agents pursuing projects
- those that view interactions socially and materially embedded in rich contexts
- eras of theories is idealised. People still work on GOMS etc
What is perception?
-how information is acquired from the environment via the different sense organs and transformed into experiences of objects, events, sounds and taste
What is cognition?
-how out mind works
-combines action, perception and memory
-deals with our perception, how we encounter the world, how we process information about it and how we store/recall it
Perception -> thinking and analysis -> memory -> action
What are the two types of cognition?
- experiential and reflective cognition
- experiential = how we act to events around us effortlessly (driving a car)
- reflective = involve mental effort, attention to judgement and decision making (writing a book)
What branches of cognition are relevant to HCI?
- perception and attention
- memory
- learning
- interdependent, and several may be involved for a given activity
What does the brains information processing depend on?
- motivation
- arousal
- individual differences
- cultural differences
What is attention?
- cognitive process of selectively concentrating on one aspect of the environment while ignoring other things
- allocation of processing resources (limited resources, we must chose wisely)
- focus on info thats relevant to the goals we want to achieve
- information has to be presented in correct way, at correct time, with little clutter to focus attention
What are some implications of perception?
- not perfect
- can be fooled
- when designing we must help users construct the correct interpretation
What is active perception?
-we search for meaning, scanning input quickly, look for meaningful patterns ignoring what doesn’t make sense or what cant easily be decoded
receive input -> assimilate it -> construct our understanding (based on experience) -> brain interprets and makes sense of input based on previous input
What are assumptions/interpretations?
- fill in missing details
- ambiguity causes us to see things differently
- the way we see the world is entirely dependent on how the brain interprets and constructs meaning
- have huge affect on design as brain can sometimes be overwhelmed
- must not bombarded user, draw their attention to appropriate information at the right times and provide fine grain details only when needed
3 types of memory and the classic view of it?
-short, working and long term
-sensory input (attention)-> STM (practice)-> LTM
-LTM affects attention, practice and STM
Working memory transfer from STM -> LTM, it is where current processing takes place, has new info plus old knowledge
What things affect memory?
- context - didnt recognise rory as he wasnt in essex
- attention - more attention given to one thing easier it is to remember
- recognition over recall
What’s wrong with STM? What can we do to solve this?
- limited capacity
- recall is easy, recognition is harder
- chunking large information into smaller blocks
- familiarity aids info processing
What is Gestalt Psychology?
- our brains want to find patterns and lump info together to make sense of the world. Has 4 laws;
- Law of proximity - if things are close to one another we group them
- law of closure - we fill things in to make shapes such as squares and circles
- law of symmetry - elements that are symmetrical to each other are seen as a group
- law of similarity - link things together that are similar and treat them as a distinct group
Features of LTM?
- very large
- associative - time needed to retrieve
- involvement in working memory process
- info can be lost before transfer to LTM thanks to disruption/interruption, anxiety and frustration
Recognition vs recall
- people are better at recognising things that have done than recalling things from memory
- eg; GUI vs command line
- recognition tasks provide memory cues that facilitate searching through memory
- sometimes recall can trump recognition; in expert interfaces it might make sense for people to learn how to use an interface dependent on the context
Implications of memory in terms of HCI
- when using a computer people are already using a lot of STM
- they are normally doing a task, using the computer as a tool
- shouldn’t have to think of the tool
- reduce memory load, don’t force people to remember info, show menus, maintain consistency, make navigation clear and obvious
What is learning?
- acquiring new knowledge, behaviours, skills, values, preferences or understanding
- people learn from experience and consequence
What is learning from consequence?
- successful actions will be repeated and vise versa
- depends on the feedback you receive (eg; nice haircut)
- crucial that feedback is timely and specific, the system should be response
- problems occur when feedback is not specific enough
- relatively easy
What are alternate ways to learn?
- web-based learning
- VR
- Internet and social media have become cognitive resources that we use in our lives daily to extend our minds
When is learning fastest?
When we can
- ID cause and affect
- use prior knowledge
- make connections
- make things obvious
How are the senses used in learning?
- meaning of sentence is same weather it is spoken, read or heard
- however ease of these 3 forms depends on the context in which it is portrayed
- need to keep speech based menus short as to not overload
- provide opportunities to make text large on screen
What does problem solving require?
- reflective cognition
- what to do? What are the options? What are the consequences?
- discussion, use of artefacts (maps in figuring out how to get around a city) and conscious process (being aware of what one is thinking about)
What are affordances?
- perceived properties of the object that suggest how one could use it (eg; chairs are designed so they are easy to sit in)
- can be used in design; website labels, slide to unlock on phones
- user should have to do as little learning as possible, they are interested in the task not the system
- help users but get the timing right; don’t prevent them from reaching their goals, make help optional
Types of affordances?
- false affordances = button that turns lights on but doesnt work, push door that says pull
- perceptible affordances = something we think does something and it does ( we think a switch turns on lights and it does)
- hidden affordances = an object has affordances that are not so obvious (looking at a beer bottle you couldnt tell you could open another bottle with it)
- correct rejection = no affordance or misperception that there is one
What are conceptual frameworks?
- explain user interaction, inform design and predict user performance
- two types; internal and external
- internal comprises of - mental models, gulfs of execution and evaluation and information processing
- external comprises of - distributed cognition, external cognition and embodied interaction
What are mental models?
- internal cognitive framework
- A successful system is one based on a conceptual model that enables users to readily learn that system and use it effectively
- people develop knowledge about a system and try to find out what to do when something does wrong
- more someone learns the more their mental model develops (we have good mental model of how TVs work)
- if people could develop better models of interactive systems, they would be in a better position to know to carry out their tasks effectively
What are the Gulfs of execution and evaluation?
- describes gap that exists between the user and the interface
- intended to design interfaces to enable users to cope with them
- Gulf of execution is distance from user to physical system
- gulf of evaluation is distance from physical system to user
- need to bridge the gulf to reduce the cognitive effort required to perform a task
What is information processing?
-info is thought to enter and exit the mind through a series of ordered processing stages
-within each stage, various processes (matching and comparing) are assumed to act upon mental representations
-Information processing model provides a basis from which to make predictions about human performance
input or stimuli -> encoding -> comparison -> response selection -> response execution -> output or response
What is distributed cognition?
- studies nature of cognitive phenomena across individuals, artefacts and internal and external representations
- focus not on what is happening inside head of individual but across a system of individuals and artefacts
- involves describing a cognitive system, which entails interactions among people, the artefacts they use and the environment they are working in
- how info is represented and re-represented as it moves across individuals and through the array of artefacts that are used during activities
What is external cognition?
-concerned with explain the cognitive process involved when we interact with different external representations
-goals are;
> externalising to reduce memory load (writing key dates into diary’s, sticky note reminders etc) helping people to remember when and what they need to do
> computational offloading - using a tool or device in conjunction with external representation to help solve problem (using pen and paper to solve maths problem
> annotations and cognitive tracing - annotating involves modifying external representations (such as crossing things off a list) and cognitive tracing involves externally manipulating items into different orders (such as reshuffling cards in a deck)
What is embodied interaction?
- about understanding interaction in terms of practical engagement with the social and physical environment
- provides a framing and organising principle to help researchers uncover issues in the design and use of existing technologies and design of new systems
What is usability?
- Refers to the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use
- how well users can learn and use product to achieve their goals
- also considered cost effectiveness and usefulness
Why do we focus on usability?
- poor usability will lead to anger, frustration, loss of time on the users end and therefore loss of audience and money on the business end
- no matter how good the information on a site is, if the usability is poor no one will go there
What does usability measure?
- Ease of learning - how fast can a new user learn it well enough to do basic tasks
- Efficiency of use - once an experienced user has learned to use the system, how fast can they do tasks
- Memorability - if a user has used the system before can they remember enough to use it effectively the next time or do they have to start over
- error frequency and severity - how often do users make errors, how serious are the errors and how does the user recover from them
- subjective satisfaction - how much does the user enjoy using the system
What are usability Heuristics?
- rules of thumb that experts use to ensure their software follows established usability principles
- Applies before software exposed to real people
- two main types; Nielsen (1993) and Norman (1988)
- both are helpful for guiding design process
- A lot of these concepts are based on our understanding of perception, memory and learning
What are Norman’s design principles? LONG
HINT: VAFMCM
Visibility - make functional parts available and easily visible (though all senses)
Affordances / constraints - Properties that things have that invite some actions / discourage action (hazard tape)
Feedback - user should be informed timely and effectively about the outcomes of the actions they are carrying out (% bars when downloading)
Mapping - relationship between controls and things controlled. Poor mapping is evident when a control does not relate with the object it affects, requiring the user to stop and think (kitchen hobs, each dial/button mapped to a specific hob)
Conceptual model - mental simulation of a devices operation (mental model), can be based on mapping’s, affordances and constraints
Metaphors - Make familiar concepts to characterise and explain unfamiliar things/events (Messy desk metaphor).
What is a key methodology for carrying out usability?
User centred design
What are Nielsen’s 10 usability heuristics? LONG
HINT: VMUCERFAHH
Visibility of system status - User must be informed of system status. What the system is doing
Match between system and the real world - system needs to speak users lang. Follow real world conventions, making info appear in natural, logical way
User control - users often chose system functions by mistakes and need a clearly marked exit
Consistency and standard - words, situations or actions must mean the same thing. Follow platform conventions and standards
Error prevention - prevent problems and errors. Provide clear messages about the effects of irreversible actions
Recognition over recall - are objects and actions visible? User should not have to remember info from one part of diag box to another
Flexibility and efficiency of use - provide shortcuts for expert users
Aesthetic and minimalist design - diags should not contain irrelevant or rarely needed information, less is more
Help user recognise, diagnose and recover from errors - error messages should be expressed in plain language (no codes) Should indicate problem and suggest a solution
Help and documentation - may be necessary to provide help and documentation. Any such info should be easy to search and has to be focused on the users
What is Heuristic evaluation?
- expert evaluators check a site against a predetermined set of usability guidelines, thereby giving your users better experience with product
- finds usability problems and makes them addressable and solvable as part of iterative design process
- evaluators work alone then discuss results to produce list of usability errors to be addressed
- can be used in conjunction with user testing but recommended use is at very beginning of design when product still in paper form
How do you carry out a Heuristic evaluation
- record problem
- write down page it was found
- Write down what you were trying to do and what happened
- write down rule it broke
- eg; when entering a password it did not state what characters I couldn’t use. I created one with a special character and it told me this was not allowed. Error prevention
What is accessibility?
- The extent to which products, services environment etc are accessible to as many diverse users as possible in as many diverse contexts as possible
- whatever kind of user you are, accessibility becomes relevant when the environment you are in makes it difficult for you to do something
What are the three main points from the 2010 equality act?
Legal requirement to….
- Make sure displaced people can have same experience as abled
- fix any physical features that make it difficult for people with disabilities to navigate the space compared to those without
- provide an aid to someone with a disability if without the aid they do not have same access as someone who is abled
What are the four categories of disabilities and impairments?
- visual (blindess)
- auditory (deafness)
- motor (paralysis)
- cognitive (memory loss, ADD, autism)
What is one big field of study in HCI in terms of accessibility?
- Colour blindness affects 4.5% of worlds population but little is done to help despite the vast amount of research and tech available
- People with the disability see the world very differently that those without (eg; traffic lights, games, MacOS has green red and amber close buttons)
What are some Do’s and Dont’s when designing for people with certain disabilities?
Motor:
Do - make large clickable buttons, give form fields space, provide shortcuts
Don’t - demand precision, bunch interactions together, have short time out windows
Low vision:
Do - use good colour contrast and readable fonts, follow a linear layout, use combination of shapes colours and text
Don’t - use low colour contrasts and small font size, use only colour to convey meaning, spread content all over page
Deaf:
Do - write in plain English, use subtitles to provide transcripts for videos, let users ask for interpreters
Don’t - create ambiguity in text, fail to provide subtitles
Autism:
Do - Use simple colours, write in plain English, use simple sentences and bullets
Don’t - use bright contrasting colours, use figures of speech and idioms, create a wall of text
What are some other categories that accessibility needs to consider?
Cultural differences:
-groups of people learn idioms (red means danger in the west but in the east its a celebratory colour)
Situational impairments:
- defined as a difficulty accessing a system due to the context or situation one is in, as opposed to a long-term physical or cognitive impact
- includes things like; breaking a bone, being drunk/high, being in a lecture (cant talk to someone on the phone)
- can combat this with; voice control (use Alexa if hands are busy), stylist/conductive gloves if its cold
What are two approaches of accessibility?
Accessible design - designing tech to be accessible
Assistive tech - using tech to make the world more accessible
What is accessible design? What are the 3 ways it can be achieved?
Design focused on diverse users to maximise the number of potential users who can readily use the system;
- Designing systems that are readily usable by most users without any modification (travellator)
- making systems adaptable to different users (car seat adjustment lever)
- Having standardised interfaces to be compatible with assistive products and tech (hearing induction loops)
What are the two steps you need to take when designing accessible systems?
Step 1:
Think about potential user groups - who will use system? Go through list of disabilities and other factors that might hinder access. ID core problems. Don’t make assumptions about user needs based on abilities
Step 2:
Research strategies to design accessibility - existing standards are a good start, look at resources that end user organisations offer, often they provide insight into daily challenges
What are standards and guidelines?
- Expert organisations analyse requirements and create lists of features and design guidelines
- Usually very extensive
What is ISO 9241-171?
- ISO guidance on software accessibility
- focused on productive software
- extremely technical and formal
What is WCAG 2.1?
- Web Content Accessibility Guidelines is a recommendation to make the web more accessible
- Has four main principles; Perceivable, operable, understandable, robust
- the full guidelines are extremely detailed and complex, they take a long time to understand and be confident in
What is the first principle of WCAG 2.1?
Perceivable
- information and UI components must be presentable to users in ways they can perceive
- Can’t be invisible to all senses
- Provide alt-text and captions
What is the second principle of WCAG 2.1?
Operable
- UI components and navigation must be operable
- interfaces cannot require interaction that a user cannot perform
- Make all functionality available from a keyboard/dont use content that could cause seizures
What is the third principle of WCAG 2.1?
Understandable
- information and operation of UI must be understandable
- content or operation cannot be beyond our understanding
- make text and content appear in readable, predictable ways
What is the fourth principle of WCAG 2.1?
Robust
- Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive tech
- as tech evolves the content should remain accessible
- maximise compatibility with current and future user tools
What are the 3 purposes of alt-text?
1) Read by screen readers in place of images, allowing the content and function of the image to be accessible to those with visual or certain cognitive disabilities
2) places instead of images if image did not load
3) Provides a semantic meaning and description to images which can be read by search engines or be used to later determine the content of the image from page context alone
What is the main rule of alt-text?
What should alt text be?
Rule: If a non-text component conveys content or function, it needs a text substitute
Alt text should;
-be accurate, be succinct, not be redundant, not use phrases “image of…” or “graphics of…”