494 midterm

Prompt: What are some examples of good, bad, and ugly design?

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Prompt: What is human factors psychology/cognitive engineering/ergonomics?

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Prompt: Describe the history of the field, training, and a typical job.

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Prompt: Why bother with human factors?

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Prompt: What is the systems approach? How does it help us to understand the 2003 blackout?

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Prompt: How do the tipping point and broken windows theory relate to the systems approach?

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Prompt: What are some common themes in human factors and ergonomics?

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why are some things easier to use

simplicity, better design

youtube: OXO good grips

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revenge effects

ironic unintended consequences of mechanical, biological, chemical, or medical systems, not a side effect or a trade off

example of a revenge effect

athritic hands cannot open child proof caps on pain killers

how to you prevent revenge effects

think of everything

dark patterns (aka deceptive design)

manipulative aspects of design in user interfaces of websites and apps that trick users into doing things they didn’t mean to

roach motel (obstruction) is an example of a BLANK design which entails

deceptive, easy subscription but hard to cancel

sneaking (hidden costs) is an example of BLANK design that entails

deceptive, hiding additional costs of a product until the last minute

what is human factors

the discovery and application of human behaviour to systems to improve human use

what is ergonomics

a discipline concerned with understanding interactions among humans and other elements of a system to optimize performance

what is cognitive engineering

cognitive demands imposed by a workplace environment

human factors combines the disciplines of BLANK, BLANK, and BLANK

design, engineering, psychology

describe the study of frederick w taylor

created the principles of scientific management to study the best way to do a job

principles of scientific management

* apply scientific method to determine most efficient way to work instead of following rules or habit
* scientifically select, train, and develop workers based on ability
* monitor performance and cooperate with workers to ensure that scientifically developed methods are applied
* allocate work to managers and workers to which they are best suited

Taylor developed BLANK methods on his case study with bethlehem steel, which entailed

time study, timing workers with a stop watch

Gilbreth and Gilbreth developed BLANK studies

motion

motion studies use a series of elemental motions called BLANK to describe actions in a job

therbligs

Mayo studied the hawthorne effect, meaning

an increase in productivity due to the knowledge that one is being observed, confounded with environmental manipulations

the hypothesis of the hawthrone effect is that worker productivity changes under observation and novelty, but some alternative explanations for the observed affect include

benign supervision (or friendly supervision), having concerns heard, feelings of belonging, novelty effects

critism’s of mayo’s studies

studied were poorly controlled, great depression increased work motivation, results not always replicable

what about world war two made the need for human factors clear

as weapons and tech got more advanced, finding “the right person” became too simplistic, and there was need for systems to be designed to be usable

over 22 months in WW2, 457 B-17 crashes were caused by

pilots retracting landing gear instead of controlling flaps

how were B-17 controls modified to prevent crashes

changed the shape of the controls to institute shape coding

shape coding

an intuitive relationship between control shape and function

common activities of human factors professionals

communication, management, system development, research and evaluation

five fallacies assumed by designers

* the design works for me so it will work for everyone else
* the design works for the average user so it will work for everyone else
* the variability of people is so great it is impossible to design something that is easy for everyone, but people will adapt
* ergonomics is expensive and products are mainly purchased on appearance and styling
* ergonomics can be applied intuitively and without data

benefits of human factors from a production view

increased sales, user satisfaction, user productivity

decreased customer support costs, development costs, employee turnover and sick leave, training costs, maintenance costs

General systems theory focuses on

arrangement of and relationships between the parts which form a whole

how does general systems theory apply the goal of unification of the sciences

the same concepts and principles of organization underlie different disciplines and provide the basis for unification

norbert wiener invented BLANK: a theory of communication and control of regulatory feedback

cybernetics

systems engineering is an interdisciplinary approach to

requirements of a system, design development production and operation, coordination of teams, automatic control of machinery

why is systems engineering holistic in nature

requires consideration of all system components, everything must interact with the system and the environment in which it operates

the systems approach examines components on a BLANK level and a BLANK level

micro, macro

micro level system components

* environment
* equipment
* interface

macro components of a system

* task design
* training
* selection and organizational design

what caused the 2003 blackout

* inadequate system understanding
* inadequate situation awareness
* inadequate tree trimming
* inadequate diagnostic support
* interacting factors at multiple levels

inadequate system understanding in the 2003 blackout\`

insufficient planning to know clevland akron area was deficient in power supply

inadequate situation awareness in 2003 blackout

alarms and computers malfunctioned, poor communication and insufficient backups

inadequate tree trimming leading to the 2003 blackout

poor maintenance, and lines sag in heat and low winds, as well as higher current

inadequate diagnostic support leading to the 2003 balckout

MISO had inadequate monitoring systems that could not identify problems, critical computer malfunctioned and was shut off as tech went for lunch

what factors interacted to cause the 2003 balckout

high demand, poor vegetation control, software failure, poor communication, mismanagement, interconnected electrical grid, poor oversight

the tipping point refers to the concept that

little things can have a big effect

the tipping point is a metaphor for

nonlinear systems

broken windows theory

fixing little things leads to less vandalism and petty crime, and prevention of major crime

conclusion of keizer, lindenberg, and steg’s 2008 study on broken windows theory

behaviour is governed by social norms, and problems arise when perception of what is common does not match expectations of society

pros and cons of broken window theory

* evidence when NYC campaign to clean up small things created drop in crime, environment is likely a determinant of behaviour
* but other factors contribute to criminal behaviour and evidence is confounded

central point of the systems appraoch

every event has determinants at multiple levels

errors are impossible to avoid so…

systems must be tolerant of error

tombstone technology

human death leads to improvement to prevent more deaths

the development of flight recorders prompted by high insurance payouts after crashes is an example of

tombstone technology

BLANK is critical in refining the performance of humans, machines, or systems

feedback

Prompt: how can perceptual abilities be quantified and what does this imply for design

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Prompt: What is J.J. Gibson’s (1979) theory of affordances? How does this concept relate to natural design?

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Prompt: Describe Don Norman’s fundamental principles of interaction: affordances/constraints, signifiers, feedback, mapping, and conceptual model.

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Prompt: What did Gillan (1994) conclude about measuring mental models?

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Prompt: How did the design of the ballot cause voter probloms in 2000

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psychophysics is the study of

the relationship between physical stimuli and mental events

Absolute threshold is

the minimum stimulus energy detected 50% of the time

difference threshold

minimum difference needed to discriminate between two stimuli 50% of the time

JND

the point where a judgement can be made between a standard and comparison stimuli

webers law

determines the just noticeable difference based on stimulus intensity

Fitt’s law measures

the information capacity of the human motor m=system

definition of fitt’s law

the time to acquire a target is a function of the distance to and size of the target

systems applications of fitt’s law

microscope work, footpedal design, computers with pointing systems

menus that are not at the edge of a computer screen take longer to correctly activate, this is an example of ignoring BLANK law, poor design

fitt’s

good design should take BLANK into consideration

perceptual abilities

changes made in the clearview highway font

increased size of lowercase letters, emphasized geometrical characteristics to aid distance viewing, reduces halation (spreading and blurring of lights)

the clearview highway font gave the greatest improvements to BLANKL drivers

older

good design should mazximise BLANK processing, BLANK and unitization, BLANK proccesing, and BLANK features, be wary of BLANK errors, and test BLANL

bottom up, automaticity, top-down, discriminating, perceptual, stimuli in the real world

how do we maximize bottom up processing

increase visual legibility, avoid confusable stimuli

how do we maximize automaticity and unitization

use familiar perceptual representations

when do we maximize top down processing

in information poor environments and when unionization is missing

how do we maximize discriminating features

use a smaller vocabulary, create context, exploit redundancy

JJ gibson studied invariants:

properties of an object that remain constant despite changes in perceivers POV

JJ gibson stressed the importance of BLANK and downplayed BLANK in perception

stimulus array, cognition

principles of JJ gibson’s theroy

* consider perception from POV of the natural observer
* consider information in dynamic experience
* optic array is full of information, mental processing unneccesary

affordance

real or perceived set of actions that a specific object or environmental situation makes available to the perceiver

affordances of the terrestrial environment

the medium, the substances, the surfaces and layouts, the objects

conclusion of Eleanor J gibson and walk visual cliff experiment

affordances do not require learning

problem with affordances

perceiving affordances correctly is probabilistic

Don norma’s definition of an affordacne

the relationship between a physical object and a given person that defines what actions are possible

constraint

a restriction of choice of action to a limited subset which contains the correct one

signifier

perceptible indicators that communicates appropriate behaviour

if an affordance cannot be perceived, a signifier may BLANK

signal its presence

feedback must be BLANK and BLANK

immediate, unambiguous

mapping

relates desired goal to means of accomplishing goal

mapping is based on

stimulus response compatibility and control-display relationship

mapping may use BLANK and BLANK

spatial analogies, cultural conventions

the designers conceptual model

the structures and functions of a system and how they are related

the system image provides BLANK

information to the user

the user’s mental model represents

belief about how the system works

skeuomorph

an interface model that allows users to predict outcomes

the user’s mental model is constructed by

the system image, the affordances and constraints, and past experiences, training, and instruction