Human factors test 1

What are human factors and what does it apply

• Designing an environment to fit human limits and capabilities

• Application of psychological science

What does our environment all include in terms of human factors in general

• social, physical psychological aspects of the environment

• items with the space (ex. equipment, tools)

What do human limits and capabilities include in terms of human factors in general

• sensory abilities (ex. visual, auditory perception)

• cognitive processing

• physiological and/or physical abilities

What kind of emphasis does human factors have and how is it different from ergonomics

Strong engineering emphasis

• includes designing tools, equipment, processes (however, they don’t always work out as we expect)

Ergonomics

• less broad than human factors

• emphasizes biomechanics, posture, force

• work to reduce fatigue and injury by focusing on the design of the environment

What fields and professions does human factors work with and draw from

• comp. sci

• architecture

• biological sciences (how we respond to environment)

• medicine (med devices, room layout)

what kind of populations do human factors work for

all populations, but it can especially create solutions to problems for special populations (children, elderly, physical/cognitive limitations)

What people/events helped advance human factors and how

• leonardo da vinci

  • explored anthropometrics and flight (looked and birds and eventually created flying machine)

• wright brothers

  • progressed human factors considerations in aviation

• WW2

  • mobilization: needs to employ and move large groups of people made it impractical to select individuals for specific jobs

  • safety and efficiency: the war’s scale required efficient and safe operation of complex systems

• time and motion studies

Who are the founders of human factors and their major contributions

• Alphonse Chapanis

  • saw human factors as the science of ensuring that design takes account of human characteristics

  • major contribution: shape coding (specifically in the aircraft cockpit in hopes to prevent confusion and therefore crashes)

• Paul M. Fitts

  • developed a model of human movement

  • Fitts Law

  • known for his studies in math models of human motion (time-accuracy trade off in phones)

Where does the work ergonomics come from

Greek words:

• Ergon “work”

• Nomos “law”

What are three factors within ergonomics and how do they interact

• Human

• machine

• environment

there are six different directional interactions (back and forth between each factor with the others)

Difference between a simple and complex ergosystem

Simple examples:

• human interacting with environment

• human interacting with machine and environment (human working on computer in room)

Complex examples

• one human working on many machines in a room (ex. one worker with many coffee machines)

• many humans working with one machine (ex. many workers with one photocopier)

what do ‘human factors’ examine

it examines the human part of ergosystem (human, machine, environment) relationships

What model does the systems theory refer to

The input-process-output (IPO) model

What is the IPO model

• the input-process-output model

• Input > process > output

• describes the structure of an information processing model

• inputs → materials, human resources, money, info, etc

• processes → activities, transformations, operations performed on the inputs etc.

• outputs → consumables, services, new information, money

Provide examples of each of the steps in the IPO model with the broad theme of : cafe to get coffee

Inputs → (customer) enters doors, navigate line, read menu, verbalise order, move to pick up line, grasp cup, add milk, navigate exit door

Processes → (store) line organization, menu displays, employee input order into computer, other employee read/interpret/produce order

Output → (product/experience) what you are left with, coffee

What has research revealed about human and machine error

It shows that human error is almost never the sole cause of poor system performance

What happened in the Three Mile Island nuclear incident and what does it reflect

It reflects a mix of human and machine error

Worst commercial nuclear power plant accident in US history

• Vent was clogged

• Signal got sent saying it needed to be closed

• Message got misinterpreted that it was already closed and didn't need help

• Lead to explosion

According to Bailey (1982) and the three mile island nuclear accident, what are the most important factors in system performance and reliability

1. design of system components, particularly human-machine interfaces

2. state of the system leading up to the incident (ex. stable/unstable, quiet/busy)

3. operators mental and physical workload

4. work organization (ex. shifts system, shift length, supervision, design of work groups)

5. external factors (ex. weather

What are anthropometrics

• anthropometrics is the data which concerns the dimension of humans

• designers need to create products that are the right size for the user and comfortable to use

why should designers be aware of anthropometrics?

• allows designers to accommodate various percentiles so the majority of people can use their product/service

• this is especially important for public spaces

What is a workspace envelope, what are the limits

• a 3D space within which you carry out physical work activities when you are in a fixed location

• the limits are determined by your functional arm reach,

• limits are also influenced by the nature of the task as tasks should be arranged within the area

What are the different parts of a workspace envelope

• primary zone- able to be more precise and fine motor skills

• secondary- elbows straighter but still some bend

• tertiary- elbows are fully stretched

Difference between typical work area and maximum work area

• typical work area is within the limits of a comfortable bent arm

• the maximum are is within comfortable reach of extended arm

What difference in considerations would you make between a light switch or the handle of a mug

• for the light switch you would need to use fingertip measurements, and for the hand you would need fist closed measurements

What are some basic principles you should think about when designing a seated work area

• relaxed upper arms and elbows at 90 degrees to help maintain straight wrists

• adequate clearance for your thighs under the work surface

• foot rest for smaller users who would not touch ground

• for fine work requiring better visibility, the work surface can be raised, but elbow support must be provided

how does a workspace envelope differ for standing work

• arms and hands are most powerful when the elbows are bent and close to sides

• for precise, fine work, the surface shoulder be higher so elbows can rest on it and so it is easier for eyes

What are some basic principles you should think about when designing a standing work area

• for work that requires the shoulder/back muscles, the surface should be 100-250mm lower than elbows

• for other tasks, the surface can be elbow height of just below

• precision work should be avoided and instead done while sitting when back muscles are support

what is vertical reach limited by and how is it measured

• vertical reach is limited by how far you can reach and grasp objects above or below your shoulder height without stretching or bending

• vertical reach measure = from shoulder to the centre of your closed hand (or extended fingertips for button operation)

List if each scenario should be designed to the smallest or largest percentile

List design examples and measurements to consider for each of these scenarios

How might a kin student draw a body differently than a fashion designer

• designers draw the body in a artistic, idealised way

• kin student would draw it proportional

Describe the aesthetic-usability effect and three reasons why it happens

Users often perceive aesthetically pleasing design as a design that is more usable

1. aesthetic things creates a positive response in user’s brain, and may lead them to believe it works better

2. individuals may be more tolerant to minor usability issues when the design is pleasing (we want to like it)

3. visually appealing design can mask usability problems and prevent issues from being discovered during usability testing

What did the study “Apparent Usability vs. Inherent Usability” look into and what did it find

• it studied the aesthetic-usability effect

• it found that user consistently rated visually pleasing designs as more usable

• even when objective measures of usability did not support this perception

What are three key factors in the aesthetic-usability effect

1. first impressions matter:

• humans are inherently visual creatures

• when we encounter a visually appealing interface, we are more likely to have a positive mindset about it

2. cognitive ease:

• aesthetically pleasing designs often convey simplicity and clarity

• makes the user feel more intuitive, reducing cognitive load required

3. trust and credibility

• convey a sense of professionalism and competence

• more likely to trust that item and assume the same level of care is applied to its functionality

Why is the perception-action cycle important

• humans learn through doing not being told

• hardwired to learn by interacting with the world around us and then perceiving the results

• neuroscientists call this the “perception-action cycle”

stages of the perception-action cycle and what do we do with them

Loop:

• information from the environment

• information to our sensory systems

• motor output

• interacting with environment

we use these stages for:

• perception (taking in information)

• action (response/behaviour)

• feedback (what outcome is observed)

• adjustment (updating for next time)

what are some individual differences that would play a part in the perception action cycle (ex. medical device design)

• experience (worked with the machine before

• colourblind

• familiarity with icons on the screen

• if you have been in the situation before you are interpreting through the screen

What did researcher find on how dancers use the perception action cycle

• they showed dancers and non dancers a dance video

• they found the brain area associated with movement was triggered more in trained dancers than non

• this is because the dancers had used the cycle through training, encoding information required to perform dance moves

• when they view the video, their brain accessed that info even though they weren’t moving

What are some ways humans vary

• physically: body, height, weight, strength

• mentally: vision, hearing , dexterity, colour vision

• personality: affecting what work they are suited for, impacting safety requirements as well

• different knowledge, experiences to draw on

Priorities to use when designing a layout and list some examples where layout would be important

• grouping controls functionally or sequentially

• consistency in layout for ease of use

• car dashboard, surgical tools

• keyboard

• piano

What layout considerations were used when designing the keyboard

• spread out common letters evenly between left and right hands

• put common letter combs together

• spreading out vowels

What reference points and zones should be taken into considerations in a workspace

• seat, arm rotation, eye reference points

• visual envelopes (optimal viewing area for displays)

• design eye position (DEP)

What is design eye position

DEP is the position from which the user is intended to view the workstation for an optimal view of the visual interface

What does a visual envelope include

• includes objects we can see without left eye, both eyes, or our right eye

What were the average angles each of the characteristics were seen in the in class activity (in our own results)

• movement- 80

• colour- 60

• shape- 40

• word 0

How do cones affect what we see in our peripherals

• cones can see colours

• they are not evenly distributed

• the amount of cones thins out towards the edge of our eyes

• the area we can really see things clearly is the biggest cluster of cones at the fovia (centre of our vision)

• this about a 20 degree window

Design considerations for placement of information

• critical information should be central

• less critical but attention-grabbing cues can be placed towards periphery, since motion grabs attention

• BUT- avoid constant unnecessary motion in peripheral= distracting and fatiguing

what details can central vision pick up compared to peripheral vision and how might this affect our designs

central- detail, text, fine shapes

peripheral vision- motion, brightness, orientation

ex. we can put something flashing further in our vision as we can still sense motion there

• could be for something less critical but still important

What are the 3 main things that need to be considered in layout design

• Dynamic measures (what is the task)

• layout priorities (what are my tools/my space)

• reference points/ zones (my functional/visual area)

How has sitting as a whole changed in through history

• we have gone from sitting in between activity to being active in between sitting

On average, how many hours do we spend sitting in a day

10.4 hours

Design considerations for chair ergonomics

• support natural “s” shape (especially lumbar)

• height for feet to rest on floor

• thighs parallel to floor to reduce pressure and promote circulation

• trunk-thigh angle ~115 degrees

• avoid crossing legs

• top of monitor at eye height

• don’t for long periods of time

what is the ideal trunk-thigh angle

115 degrees

Is there a perfect ergonomic chair, why or why not and if so why isn’t is used everywhere

no, there isn’t one perfect ergonomic chair. each situation requires specific types of seating

• because humans aren’t meant to sit in one spot for a long time, we are meant to move positions

• ex. bleashers to fit lots of people

• ex. hammock to be comfortable

When driving a car, what does the human, environment, and machine each bring to the table? What are some interactions between these factors

environment

• icy, snowy conditions

• visibility

• traffic, other cars in general

human

• height

• experience driving

• level of alertness

machine

• button placement

• condition of vehicle

• amount of blind spots

interactions:

• human forgot glasses, can’t read signs in environment

• press button on machine to let other drivers know our direction

• experience of driver knowing how to drive in bad weather

• all three: hot outside, press button for ac, human feels cooler

what does compatibility refer to in human factors

refers to the relationship of stimuli and responses to humans expectations (expected or unexpected result?)

what are the correspondence between stimuli and response locations (spatial compatibility) an important determinant of

important determinant of speed of response

Types of compatibility

1. spatial compatibility

• the physical, spatial arrangement of controls and their associated displays

2. conceptual compatibility

• the degree to which codes and symbols correspond to conceptual associations (how meaningful are they)

• ex. an airport symbol in some countries aren’t as intuitive as others

3. movement compatibility

• the movement of displays and controls relative to the response of the system being displayed or controlled

• ex. a clockwise movement of a control knob usually means an increase in the control parameter

• ex. rolling a dice harder makes you believe it will be larger

4. modality compatibility

• certain S-R modality combinations are more compatible with some tasks than with others

• ex. a verbal response to a verbal command is faster than a manual response and vice versa

ambiguous or clear?

Types of grip

• pinch (x2)

• span

• disc (x2)

• hook

• power

• flat hand push

• finger push

Difference between continuous and discrete information and examples

• discrete: limited number of outcomes possible

  • less options (on/off, open/closed, 4 levels)

  • ex. elevator buttons, pedal click, toggle, a/c levels in car

• continuous: all decimals of possible outcomes between two defined point

  • almost infinite amount

  • ex. volume knob, window crank, steering wheel, pedal

What factors affect which coding methods are used for hands/handles

the coding method depends on the situation

• the demands of the operator

• the coding methods already being used

• the level of illumination

• speed and curacy required for control identification

• available space

• number of controls that must be coded

What does shape coding use and how does it work

• uses tactile sensitivity

• control can functionally associate shape with end-use

• ex. landing flap lever in an airplane is shaped like a landing flap, landing gear lever is shaped like the wheels

How does texture coding work and example

Controls can be coded by texture

• door knobs

How does shape coding work and example

• shape can affect coding

• ex. does one knob need to be larger than the rest as it is used more

• not as useful as shape coding

• ex. volume board

Types of coding for controls (hands/handles)

• shape

• texture

• size

• location

• colour

• label

How can location coding help and example

• distances between things must be sufficient for discrimination but not too large to not reduce functionality

• ex. moving your foot from the accelerator to the brake

how does colour coding work

• fewer colours should be used (~5)

• colour coding should be reserved for especially meaningful controls (ex. red for emergency)

• perception of colour varies with illumination

• can be combined with other codes

label coding and problems that could happen

• widely used method for coding

• not recommended to be used as the sole indicator of control

• problems

  • they take time to read

  • they must be placed so that the hand doesn’t cover the label while engaging the control

  • must be kept clean and well illuminated

Principles to consider for handle design

• shape and size: cylindrical, spherical, custom shapes

• material and texture: non-slip materials, cushioning

• handle length and diameter: optimal dimensions for different tasks

• force distribution: even distribution to reduce strain

big takeaway from the course about labels

if something needs a label explaining, it is not intuitive enough

safety considerations for door handles, how to change for it

• in case of emergency, most building doors are push to exit

• push/pull handles need to be intuitive enough to know it is a push

• push handles should look like they can be pushed and no other option (should not need a handle)

What does UIUX stand for

user interface, user experience

why is it important to have